/* ============================================================
   Quantitative & Verbal Reasoning for AI/ML
   Electric Sheep Africa — 2026
   Newspaper-Style Light Mode Stylesheet
   ============================================================ */

/* ---------- RESET & CUSTOM PROPERTIES ---------- */
*, *::before, *::after { margin: 0; padding: 0; box-sizing: border-box; }

:root {
    /* Newspaper palette */
    --paper:         #FAF8F5;
    --paper-warm:    #F5F2EC;
    --paper-card:    #FFFFFF;
    --paper-elevated:#FFFFFF;
    --paper-hover:   #F0EDE7;

    --ink:           #1A1A1A;
    --ink-secondary: #4A4A4A;
    --ink-muted:     #8A8A80;
    --ink-faint:     #B5B0A8;

    --rule:          #D8D3CB;
    --rule-strong:   #B5B0A8;
    --rule-accent:   #1A1A1A;

    --accent:        #2C2C2C;
    --accent-warm:   #8B6914;
    --accent-hover:  #1A1A1A;

    --link:          #1A1A1A;
    --link-hover:    #000000;

    /* Typography */
    --serif-display: 'Playfair Display', Georgia, 'Times New Roman', serif;
    --serif-body:    'Source Serif 4', 'Source Serif Pro', Georgia, serif;
    --sans:          'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    --mono:          'Courier Prime', 'Courier New', Consolas, monospace;

    /* Type scale (fluid) */
    --text-xs:   clamp(0.65rem, 0.6rem + 0.25vw, 0.75rem);
    --text-sm:   clamp(0.75rem, 0.7rem + 0.25vw, 0.875rem);
    --text-base: clamp(0.95rem, 0.9rem + 0.25vw, 1.075rem);
    --text-lg:   clamp(1.05rem, 0.95rem + 0.5vw, 1.2rem);
    --text-xl:   clamp(1.2rem, 1rem + 1vw, 1.6rem);
    --text-2xl:  clamp(1.6rem, 1.2rem + 2vw, 2.2rem);
    --text-3xl:  clamp(2rem, 1.5rem + 2.5vw, 3rem);
    --text-4xl:  clamp(2.5rem, 1.5rem + 4vw, 4rem);
    --text-hero: clamp(3rem, 2rem + 5vw, 5rem);

    /* Spacing (compact) */
    --space-xs:  0.2rem;
    --space-sm:  0.4rem;
    --space-md:  0.75rem;
    --space-lg:  1rem;
    --space-xl:  1.5rem;
    --space-2xl: 2.5rem;
    --space-3xl: 3.5rem;

    /* Layout */
    --max-width:       1140px;
    --max-read:        720px;
    --nav-height:      64px;

    /* Transitions */
    --ease: cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --transition-fast: 0.15s var(--ease);
    --transition:      0.3s var(--ease);

    /* Borders */
    --radius:    3px;
}

/* ---------- BASE ---------- */
html {
    scroll-behavior: smooth;
    font-size: 16px;
    scroll-padding-top: calc(var(--nav-height) + 2rem);
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: var(--serif-body);
    background: var(--paper);
    color: var(--ink);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

::selection {
    background: var(--ink);
    color: var(--paper);
}

a {
    color: var(--link);
    text-decoration: none;
    transition: color var(--transition-fast);
    border-bottom: 1px solid var(--rule);
}
a:hover {
    color: var(--link-hover);
    border-bottom-color: var(--ink);
}

img { max-width: 100%; display: block; }

/* ---------- UTILITIES ---------- */
.container     { max-width: var(--max-width); margin: 0 auto; padding: 0 2rem; }
.container--narrow { max-width: var(--max-read); margin: 0 auto; padding: 0 2rem; }

.sr-only {
    position: absolute; width: 1px; height: 1px;
    padding: 0; margin: -1px; overflow: hidden;
    clip: rect(0,0,0,0); white-space: nowrap; border: 0;
}

section { padding: var(--space-2xl) 0; }

/* ---------- NAVIGATION ---------- */
.nav {
    position: fixed;
    top: 0; left: 0; right: 0;
    z-index: 1000;
    height: var(--nav-height);
    background: rgba(250, 248, 245, 0.92);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--rule);
    transition: background var(--transition);
}

.nav__inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 2rem;
}

.nav__brand {
    display: flex;
    align-items: center;
    font-family: var(--serif-display);
    font-size: 1.1rem;
    font-weight: 700;
    color: var(--ink);
    letter-spacing: 0.02em;
    white-space: nowrap;
    border-bottom: none;
    text-decoration: none;
}
.nav__brand:hover { color: var(--ink); border-bottom: none; }

.nav__logo {
    height: 36px;
    width: auto;
    display: block;
}

.nav__links {
    display: flex;
    gap: 0;
    list-style: none;
    align-items: center;
}

.nav__links a {
    font-family: var(--sans);
    font-size: 0.68rem;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink-muted);
    padding: 0.5rem 0.85rem;
    border-bottom: 2px solid transparent;
    transition: all var(--transition-fast);
    white-space: nowrap;
}
.nav__links a:hover { color: var(--ink); border-bottom-color: transparent; }
.nav__links a.active {
    color: var(--ink);
    border-bottom-color: var(--ink);
}

.nav__hamburger {
    display: none;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.5rem;
    flex-direction: column;
    gap: 5px;
}
.nav__hamburger span {
    display: block;
    width: 22px;
    height: 1.5px;
    background: var(--ink);
    transition: all var(--transition);
    transform-origin: center;
}

/* ---------- HERO (Landing) ---------- */
.hero {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 5rem 2rem 3rem;
    position: relative;
    overflow: hidden;
    border-bottom: 1px solid var(--rule);
}

.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(ellipse 60% 40% at 50% 20%, rgba(139, 105, 20, 0.03) 0%, transparent 60%);
    pointer-events: none;
}

.hero__brand {
    font-family: var(--sans);
    font-size: 0.7rem;
    letter-spacing: 0.35em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 2.5rem;
    position: relative;
}

.hero__title {
    font-family: var(--serif-display);
    font-size: var(--text-hero);
    font-weight: 900;
    line-height: 1.05;
    color: var(--ink);
    max-width: 900px;
    margin-bottom: 1.5rem;
    position: relative;
    letter-spacing: -0.02em;
}

.hero__subtitle {
    font-family: var(--serif-body);
    font-size: var(--text-lg);
    font-weight: 400;
    font-style: italic;
    color: var(--ink-secondary);
    margin-bottom: 2.5rem;
    position: relative;
}

.hero__stats {
    display: flex;
    gap: 0;
    margin-bottom: 2.5rem;
    position: relative;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
}

.hero__stat {
    padding: 1.2rem 2rem;
    text-align: center;
    border-right: 1px solid var(--rule);
}
.hero__stat:last-child { border-right: none; }

.hero__stat-value {
    font-family: var(--serif-display);
    font-size: 2rem;
    font-weight: 900;
    color: var(--ink);
    line-height: 1;
    margin-bottom: 0.3rem;
}

.hero__stat-label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 500;
}

.hero__cta {
    display: inline-flex;
    align-items: center;
    gap: 0.75rem;
    font-family: var(--sans);
    font-size: 0.72rem;
    font-weight: 600;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    padding: 1rem 2.5rem;
    border: 1px solid var(--ink);
    color: var(--paper);
    background: var(--ink);
    transition: all var(--transition);
    position: relative;
}
.hero__cta:hover {
    background: var(--paper);
    color: var(--ink);
    transform: translateY(-2px);
    border-bottom-color: var(--ink);
}
.hero__cta svg {
    width: 14px;
    height: 14px;
    transition: transform var(--transition);
}
.hero__cta:hover svg { transform: translateX(4px); }

.hero__scroll {
    position: absolute;
    bottom: 2.5rem;
    left: 50%;
    transform: translateX(-50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.6rem;
    color: var(--ink-faint);
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    font-weight: 500;
    animation: float 3s ease-in-out infinite;
}
.hero__scroll-line {
    width: 1px;
    height: 32px;
    background: linear-gradient(to bottom, var(--ink-faint), transparent);
}

@keyframes float {
    0%, 100% { transform: translateX(-50%) translateY(0); }
    50% { transform: translateX(-50%) translateY(6px); }
}

/* ---------- PAGE HERO (Week pages) ---------- */
.page-hero {
    padding: 6rem 2rem 2.5rem;
    text-align: center;
    position: relative;
    border-bottom: 1px solid var(--rule);
}

.page-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: radial-gradient(ellipse 60% 60% at 50% 0%, rgba(139, 105, 20, 0.02) 0%, transparent 60%);
    pointer-events: none;
}

.page-hero__back {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    font-family: var(--sans);
    font-size: 0.65rem;
    font-weight: 500;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 2rem;
    transition: color var(--transition-fast);
    position: relative;
}
.page-hero__back:hover { color: var(--ink); }
.page-hero__back svg { width: 14px; height: 14px; }

.page-hero__week {
    font-family: var(--serif-display);
    font-size: 10rem;
    font-weight: 900;
    line-height: 1;
    color: var(--ink);
    opacity: 0.04;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    pointer-events: none;
    user-select: none;
    letter-spacing: -0.04em;
}

.page-hero__label {
    font-family: var(--sans);
    font-size: 0.65rem;
    letter-spacing: 0.28em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 1rem;
    position: relative;
    font-weight: 700;
}

.page-hero__title {
    font-family: var(--serif-display);
    font-size: var(--text-3xl);
    font-weight: 900;
    color: var(--ink);
    margin-bottom: 1rem;
    position: relative;
    letter-spacing: -0.02em;
}

.page-hero__goal {
    max-width: var(--max-read);
    margin: 0 auto;
    font-size: var(--text-base);
    line-height: 1.85;
    color: var(--ink-secondary);
    position: relative;
}

/* ---------- SECTION HEADERS ---------- */
.section-header {
    text-align: center;
    margin-bottom: 2.5rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--rule);
}

.section-header__label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.3em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.75rem;
    font-weight: 700;
}

.section-header__title {
    font-family: var(--serif-display);
    font-size: var(--text-2xl);
    font-weight: 900;
    color: var(--ink);
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.section-header__subtitle {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    color: var(--ink-secondary);
    max-width: 580px;
    margin: 0 auto;
    line-height: 1.75;
    font-style: italic;
}

/* ---------- OVERVIEW GRID ---------- */
.overview {
    border-bottom: 1px solid var(--rule);
}

.overview__grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 0;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
    margin-bottom: 2.5rem;
}

.overview__stat {
    text-align: center;
    padding: 1.8rem 1.5rem;
    border-right: 1px solid var(--rule);
    transition: background var(--transition);
}
.overview__stat:last-child { border-right: none; }
.overview__stat:hover { background: var(--paper-warm); }

.overview__stat-value {
    font-family: var(--serif-display);
    font-size: 3rem;
    font-weight: 900;
    color: var(--ink);
    line-height: 1;
    margin-bottom: 0.5rem;
}

.overview__stat-label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
}

.overview__description {
    max-width: var(--max-read);
    margin: 0 auto;
    text-align: center;
    font-size: var(--text-lg);
    line-height: 1.75;
    color: var(--ink-secondary);
}

.overview__detail {
    max-width: var(--max-read);
    margin: 1rem auto 0;
    text-align: center;
    font-size: var(--text-sm);
    line-height: 1.7;
    color: var(--ink-muted);
}
.overview__detail strong { color: var(--ink-secondary); }

.overview__badges {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 0.5rem;
    margin-top: 2rem;
}

.badge {
    font-family: var(--sans);
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.35rem 0.85rem;
    border: 1px solid var(--rule-strong);
    color: var(--ink-secondary);
    transition: all var(--transition);
    background: transparent;
}
.badge:hover {
    background: var(--ink);
    color: var(--paper);
    border-color: var(--ink);
}

/* ---------- WEEK CARDS (landing page) ---------- */
.weeks-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 0;
    border-top: 2px solid var(--ink);
}

.week-card {
    display: flex;
    flex-direction: column;
    padding: 2rem;
    border-bottom: 1px solid var(--rule);
    border-right: 1px solid var(--rule);
    transition: all var(--transition);
    text-decoration: none;
    position: relative;
    overflow: hidden;
}
.week-card:nth-child(2n) { border-right: none; }
.week-card:hover {
    background: var(--paper-warm);
}

.week-card__number {
    font-family: var(--serif-display);
    font-size: 4rem;
    font-weight: 900;
    line-height: 1;
    color: var(--ink);
    opacity: 0.05;
    position: absolute;
    top: 0.5rem;
    right: 1rem;
    letter-spacing: -0.04em;
}

.week-card__label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.week-card__title {
    font-family: var(--serif-display);
    font-size: 1.3rem;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: 0.75rem;
}

.week-card__sessions {
    font-family: var(--serif-body);
    font-size: 0.85rem;
    line-height: 1.85;
    color: var(--ink-secondary);
    flex-grow: 1;
}

.week-card__arrow {
    display: flex;
    align-items: center;
    gap: 0.4rem;
    font-family: var(--sans);
    font-size: 0.62rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-top: 1.5rem;
    font-weight: 600;
    transition: color var(--transition-fast);
    border-bottom: none;
}
.week-card:hover .week-card__arrow { color: var(--ink); border-bottom: none; }
.week-card__arrow svg {
    width: 14px;
    height: 14px;
    transition: transform var(--transition);
}
.week-card:hover .week-card__arrow svg { transform: translateX(4px); }

/* ---------- SCHEDULE TABLE ---------- */
.schedule {
    background: var(--paper-warm);
    border-top: 1px solid var(--rule);
    border-bottom: 1px solid var(--rule);
}

.schedule-table {
    width: 100%;
    border-collapse: collapse;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
}

.schedule-table thead th {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    text-align: left;
    padding: 1rem 1.5rem;
    border-bottom: 1px solid var(--rule-strong);
    font-weight: 600;
}

.schedule-table tbody tr {
    border-bottom: 1px solid var(--rule);
    transition: background var(--transition-fast);
}
.schedule-table tbody tr:last-child { border-bottom: none; }
.schedule-table tbody tr:hover { background: var(--paper-hover); }

.schedule-table td {
    padding: 1.2rem 1.5rem;
    vertical-align: top;
}

.schedule-table .week-label {
    font-family: var(--serif-display);
    font-weight: 700;
    font-size: 1rem;
    color: var(--ink);
    white-space: nowrap;
}

.schedule-table .week-theme {
    font-family: var(--serif-body);
    font-style: italic;
    font-size: 1rem;
    color: var(--ink-secondary);
}

.schedule-table .week-sessions {
    font-family: var(--serif-body);
    font-size: 0.88rem;
    line-height: 1.9;
    color: var(--ink-secondary);
}

/* ---------- SESSION CARDS (week pages) ---------- */
.session-card {
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
    margin-bottom: 2rem;
}

.session-card:hover { }

.session-card__header {
    padding: 1rem 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.75rem;
    border-bottom: 1px solid var(--rule);
}

.session-card__number {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.25rem;
    font-weight: 600;
}

.session-card__title {
    font-family: var(--serif-display);
    font-size: var(--text-xl);
    font-weight: 900;
    color: var(--ink);
}

.session-card__subtitle {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    font-style: italic;
    color: var(--ink-secondary);
    margin-top: 0.25rem;
}

.session-card__meta {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.14em;
    text-transform: uppercase;
    color: var(--ink-muted);
    padding: 0.25rem 0.75rem;
    border: 1px solid var(--rule-strong);
    font-weight: 700;
}

.session-card__body { padding: 1.5rem 0; }

.session-card__objective {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    color: var(--ink-secondary);
    padding: 0.9rem 1.2rem;
    background: var(--paper-warm);
    border-left: 3px solid var(--ink);
    margin-bottom: 1.5rem;
    line-height: 1.65;
}
.session-card__objective strong {
    display: block;
    font-family: var(--sans);
    font-size: 0.58rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.3rem;
    font-weight: 700;
}

/* ---------- CONCEPT LESSON ---------- */
.concept-lesson { margin-bottom: 1.5rem; }

.concept-lesson__label,
.exercises__label {
    font-family: var(--sans);
    font-size: 0.58rem;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 1px solid var(--rule);
    font-weight: 700;
}

.concept-lesson p {
    margin-bottom: 1rem;
    font-size: var(--text-base);
    line-height: 1.7;
    color: var(--ink-secondary);
    text-align: justify;
    hyphens: auto;
}

/* ---------- EXERCISES ---------- */
.exercises { margin-bottom: 1.5rem; }

.exercise-item {
    padding: 0.9rem 1.2rem;
    margin-bottom: 0.35rem;
    background: var(--paper-warm);
    border-left: 2px solid var(--rule-strong);
    font-family: var(--serif-body);
    font-size: var(--text-base);
    line-height: 1.65;
    color: var(--ink-secondary);
    transition: border-color var(--transition-fast);
}
.exercise-item:hover { border-left-color: var(--ink); }

.exercise-item strong {
    color: var(--ink);
    font-family: var(--sans);
    font-size: 0.65rem;
    letter-spacing: 0.06em;
    font-weight: 700;
    text-transform: uppercase;
}

/* ---------- DISCUSSION ---------- */
.discussion {
    padding: 1rem 1.2rem;
    border: 1px solid var(--rule);
    border-top: 2px solid var(--ink);
    margin-bottom: 1.25rem;
}

.discussion__label {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.5rem;
    font-weight: 700;
}

.discussion p {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    line-height: 1.85;
    font-style: italic;
    color: var(--ink-secondary);
}

/* ---------- KEY TAKEAWAY ---------- */
.takeaway {
    padding: 1rem 1.2rem;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
    margin-top: 0.25rem;
}

.takeaway__label {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.25em;
    text-transform: uppercase;
    color: var(--ink-muted);
    margin-bottom: 0.35rem;
    font-weight: 700;
}

.takeaway p {
    color: var(--ink);
    font-family: var(--serif-display);
    font-size: var(--text-lg);
    font-weight: 900;
    line-height: 1.5;
}

/* ---------- RUBRIC TABLE ---------- */
.rubric-table {
    width: 100%;
    border-collapse: collapse;
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
}

.rubric-table thead th {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--ink);
    padding: 1rem 1.2rem;
    text-align: left;
    border-bottom: 1px solid var(--rule-strong);
    font-weight: 600;
}

.rubric-table tbody td {
    padding: 1rem 1.2rem;
    border-bottom: 1px solid var(--rule);
    font-family: var(--serif-body);
    font-size: 0.9rem;
    line-height: 1.7;
    vertical-align: top;
    color: var(--ink-secondary);
}
.rubric-table tbody tr:last-child td { border-bottom: none; }
.rubric-table tbody tr:hover td { background: var(--paper-warm); }

.rubric-table td:first-child {
    font-weight: 700;
    font-family: var(--serif-display);
    color: var(--ink);
    white-space: nowrap;
}

/* ---------- INSTRUCTOR NOTES ---------- */
.note-block {
    padding: 1.5rem 2rem;
    margin-bottom: 1rem;
    border-left: 3px solid var(--ink);
    background: var(--paper-warm);
}

.note-block__title {
    font-family: var(--serif-display);
    font-size: 1.05rem;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: 0.75rem;
}

.note-block p {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    line-height: 1.85;
    color: var(--ink-secondary);
}

/* ---------- WEEK NAV (prev/next) ---------- */
.week-nav {
    display: flex;
    justify-content: space-between;
    gap: 1rem;
    padding: 2rem 0;
    border-top: 2px solid var(--ink);
}

.week-nav__link {
    display: flex;
    flex-direction: column;
    gap: 0.2rem;
    padding: 1rem 1.5rem;
    border: 1px solid var(--rule);
    transition: all var(--transition);
    flex: 1;
    max-width: 50%;
    border-bottom: 1px solid var(--rule);
}
.week-nav__link:hover {
    background: var(--paper-warm);
    border-bottom: 1px solid var(--rule);
}
.week-nav__link--next { text-align: right; margin-left: auto; }

.week-nav__label {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.22em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
}

.week-nav__title {
    font-family: var(--serif-display);
    font-size: 1.05rem;
    font-weight: 900;
    color: var(--ink);
}

/* ---------- FOOTER ---------- */
.footer {
    background: var(--paper-warm);
    border-top: 2px solid var(--ink);
    padding: 2.5rem 2rem;
    text-align: center;
}

.footer__brand {
    font-family: var(--serif-display);
    font-size: 1.2rem;
    font-weight: 900;
    color: var(--ink);
    margin-bottom: 0.3rem;
}

.footer__tagline {
    font-family: var(--serif-body);
    font-size: 0.8rem;
    color: var(--ink-muted);
    font-style: italic;
    margin-bottom: 1.5rem;
}

.footer__links {
    display: flex;
    justify-content: center;
    gap: 1.5rem;
    flex-wrap: wrap;
    margin-bottom: 1.5rem;
}

.footer__links a {
    font-family: var(--sans);
    font-size: 0.62rem;
    letter-spacing: 0.16em;
    text-transform: uppercase;
    color: var(--ink-muted);
    transition: color var(--transition-fast);
    font-weight: 500;
}
.footer__links a:hover { color: var(--ink); }

.footer__copy {
    font-family: var(--sans);
    font-size: 0.65rem;
    color: var(--ink-faint);
}

/* ---------- FADE-IN ANIMATION ---------- */
.fade-in {
    opacity: 0;
    transform: translateY(20px);
    transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}
.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ---------- RESPONSIVE ---------- */
@media (max-width: 900px) {
    .overview__grid { grid-template-columns: repeat(2, 1fr); }
    .overview__stat:nth-child(2) { border-right: none; }

    .weeks-grid { grid-template-columns: 1fr; }
    .week-card { border-right: none !important; }

    .hero__stats { flex-wrap: wrap; }
    .hero__stat { flex: 1 1 45%; border-bottom: 1px solid var(--rule); }
    .hero__stat:nth-child(2) { border-right: none; }
    .hero__stat:nth-child(3),
    .hero__stat:nth-child(4) { border-bottom: none; }
}

@media (max-width: 768px) {
    :root { --nav-height: 56px; }
    section { padding: var(--space-2xl) 0; }

    .nav__links { display: none; }
    .nav__hamburger { display: flex; }

    .nav.open .nav__links {
        display: flex;
        flex-direction: column;
        position: fixed;
        top: var(--nav-height);
        left: 0; right: 0; bottom: 0;
        background: rgba(250, 248, 245, 0.98);
        backdrop-filter: blur(12px);
        padding: 2rem;
        gap: 0.25rem;
        overflow-y: auto;
    }
    .nav.open .nav__links a {
        font-size: 0.8rem;
        padding: 1rem;
        border-bottom: 1px solid var(--rule);
    }

    .nav.open .nav__hamburger span:nth-child(1) { transform: rotate(45deg) translate(4px, 5px); }
    .nav.open .nav__hamburger span:nth-child(2) { opacity: 0; }
    .nav.open .nav__hamburger span:nth-child(3) { transform: rotate(-45deg) translate(4px, -5px); }

    .hero__stats { flex-direction: column; }
    .hero__stat { border-right: none; border-bottom: 1px solid var(--rule); }
    .hero__stat:last-child { border-bottom: none; }

    .overview__grid { grid-template-columns: repeat(2, 1fr); }

    .session-card__header { flex-direction: column; align-items: flex-start; }

    .page-hero__week { font-size: 6rem; }

    .week-nav { flex-direction: column; }
    .week-nav__link { max-width: 100%; }
    .week-nav__link--next { text-align: left; }

    .concept-lesson p { text-align: left; hyphens: none; }

    /* Responsive tables */
    .schedule-table, .schedule-table thead, .schedule-table tbody,
    .schedule-table th, .schedule-table td, .schedule-table tr { display: block; }
    .schedule-table thead { display: none; }
    .schedule-table tr {
        margin-bottom: 0;
        border-bottom: 1px solid var(--rule);
    }
    .schedule-table td { padding: 0.8rem 1.2rem; border-bottom: 1px solid var(--rule); }
    .schedule-table td:last-child { border-bottom: none; }
    .schedule-table td::before {
        content: attr(data-label);
        font-family: var(--sans);
        font-size: 0.55rem;
        letter-spacing: 0.18em;
        text-transform: uppercase;
        color: var(--ink-muted);
        display: block;
        margin-bottom: 0.3rem;
        font-weight: 600;
    }

    .rubric-table, .rubric-table thead, .rubric-table tbody,
    .rubric-table th, .rubric-table td, .rubric-table tr { display: block; }
    .rubric-table thead { display: none; }
    .rubric-table tr {
        margin-bottom: 0;
        border-bottom: 1px solid var(--rule);
    }
    .rubric-table td { border-bottom: 1px solid var(--rule); }
    .rubric-table td:last-child { border-bottom: none; }
    .rubric-table td::before {
        content: attr(data-label);
        font-family: var(--sans);
        font-size: 0.55rem;
        letter-spacing: 0.18em;
        text-transform: uppercase;
        color: var(--ink-muted);
        display: block;
        margin-bottom: 0.3rem;
        font-weight: 600;
    }
}

@media (max-width: 480px) {
    .container, .container--narrow { padding: 0 1.25rem; }

    .overview__grid { grid-template-columns: 1fr 1fr; }
    .overview__stat { padding: 1.5rem 1rem; }
    .overview__stat-value { font-size: 2.2rem; }

    .session-card__body { padding: 1.5rem 0; }

    .exercise-item { padding: 1rem; }

    .discussion { padding: 1.2rem; }

    .takeaway { padding: 1.2rem; }

    .note-block { padding: 1.2rem; }

    .hero__stat { padding: 1.2rem 1.5rem; }
}

/* ========== NEW FEATURES ========== */

/* ---------- DARK MODE ---------- */
[data-theme="dark"] {
    --paper:         #1A1A1C;
    --paper-warm:    #222224;
    --paper-card:    #2A2A2D;
    --paper-elevated:#2A2A2D;
    --paper-hover:   #333336;
    --ink:           #E8E6E3;
    --ink-secondary: #B0AEA8;
    --ink-muted:     #787570;
    --ink-faint:     #504E4A;
    --rule:          #3A3A3D;
    --rule-strong:   #504E4A;
    --rule-accent:   #E8E6E3;
    --accent-warm:   #C9A227;
    --link:          #E8E6E3;
    --link-hover:    #FFFFFF;
}

[data-theme="dark"] .nav {
    background: rgba(26, 26, 28, 0.92);
}
[data-theme="dark"] .nav.open .nav__links {
    background: rgba(26, 26, 28, 0.98);
}
[data-theme="dark"] .hero__cta {
    background: var(--ink);
    color: var(--paper);
}
[data-theme="dark"] .hero__cta:hover {
    background: var(--paper);
    color: var(--ink);
}
[data-theme="dark"] .nav__logo {
    filter: invert(1) brightness(1.1);
}
[data-theme="dark"] .footer__brand {
    filter: none;
}

/* ---------- DARK MODE TOGGLE ---------- */
.dark-toggle {
    background: none;
    border: 1px solid var(--rule-strong);
    padding: 0.35rem 0.6rem;
    cursor: pointer;
    font-size: 0.85rem;
    border-radius: 2px;
    color: var(--ink-secondary);
    transition: all var(--transition-fast);
    line-height: 1;
    font-family: var(--sans);
}
.dark-toggle:hover {
    border-color: var(--ink);
    color: var(--ink);
}

/* ---------- PROGRESS BAR (index page) ---------- */
.progress-bar {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 1.5rem 2rem;
}
.progress-bar__track {
    height: 4px;
    background: var(--rule);
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 0.5rem;
}
.progress-bar__fill {
    height: 100%;
    background: var(--ink);
    transition: width 0.5s var(--ease);
    border-radius: 2px;
}
.progress-bar__label {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
}

/* ---------- SESSION CHECKBOX (week pages) ---------- */
.session-check {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-bottom: 0.5rem;
    cursor: pointer;
    font-family: var(--sans);
    font-size: 0.65rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
    user-select: none;
}
.session-check input[type="checkbox"] {
    appearance: none;
    -webkit-appearance: none;
    width: 16px;
    height: 16px;
    border: 1.5px solid var(--rule-strong);
    border-radius: 2px;
    cursor: pointer;
    position: relative;
    transition: all var(--transition-fast);
    flex-shrink: 0;
}
.session-check input[type="checkbox"]:checked {
    background: var(--ink);
    border-color: var(--ink);
}
.session-check input[type="checkbox"]:checked::after {
    content: '✓';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    color: var(--paper);
    font-size: 0.6rem;
    font-weight: 700;
}
.session-check.completed {
    color: var(--ink);
}

/* ---------- READING TIME ---------- */
.reading-time {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-faint);
    font-weight: 500;
    margin-left: 0.75rem;
}

/* ---------- TABLE OF CONTENTS (mini TOC) ---------- */
.mini-toc {
    position: sticky;
    top: calc(var(--nav-height) + 1rem);
    float: right;
    width: 200px;
    margin-left: 1.5rem;
    margin-bottom: 1rem;
    padding: 1rem;
    border-left: 2px solid var(--rule);
    z-index: 10;
}
.mini-toc__title {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 0.75rem;
}
.mini-toc a {
    display: block;
    font-family: var(--sans);
    font-size: 0.7rem;
    color: var(--ink-muted);
    padding: 0.25rem 0;
    border-bottom: none;
    transition: color var(--transition-fast);
    line-height: 1.4;
}
.mini-toc a:hover,
.mini-toc a.active {
    color: var(--ink);
    border-bottom: none;
}

/* ---------- COLLAPSIBLE SECTIONS ---------- */
.collapsible {
    position: relative;
}
.collapsible__toggle {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.3rem 0;
    margin-top: 0.5rem;
    transition: color var(--transition-fast);
}
.collapsible__toggle:hover { color: var(--ink); }
.collapsible__toggle svg {
    width: 12px;
    height: 12px;
    transition: transform var(--transition);
}
.collapsible__content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s var(--ease);
}
.collapsible__content.expanded {
    max-height: 5000px;
}

/* ---------- FORMULA CALLOUT ---------- */
.formula-box {
    padding: 1rem 1.25rem;
    margin: 1rem 0;
    background: var(--paper-warm);
    border: 1px solid var(--rule);
    border-left: 3px solid var(--ink);
    font-family: var(--mono);
    font-size: 0.9rem;
    line-height: 1.7;
    color: var(--ink);
    text-align: center;
}
.formula-box__label {
    font-family: var(--sans);
    font-size: 0.5rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 0.5rem;
    text-align: left;
}

/* ---------- PREREQUISITE GATE ---------- */
.prereq {
    padding: 0.9rem 1.2rem;
    margin-top: 1.5rem;
    margin-bottom: 1.5rem;
    border: 1px solid var(--rule);
    font-family: var(--sans);
    font-size: 0.75rem;
    color: var(--ink-secondary);
    line-height: 1.7;
    position: relative;
    z-index: 5;
    background: var(--paper);
}
.prereq__title {
    font-size: 0.55rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 0.4rem;
}
.prereq a {
    color: var(--ink);
    font-weight: 600;
}

/* ---------- QUIZ ---------- */
.quiz {
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
    padding: 1.5rem 0;
    margin-top: 2rem;
}
.quiz__title {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 1.25rem;
}
.quiz__question {
    margin-bottom: 1.25rem;
    padding-bottom: 1.25rem;
    border-bottom: 1px solid var(--rule);
}
.quiz__question:last-of-type {
    border-bottom: none;
}
.quiz__q-text {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    line-height: 1.65;
    color: var(--ink);
    margin-bottom: 0.75rem;
}
.quiz__options {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
}
.quiz__option {
    display: flex;
    align-items: flex-start;
    gap: 0.6rem;
    padding: 0.5rem 0.75rem;
    cursor: pointer;
    font-family: var(--serif-body);
    font-size: 0.9rem;
    line-height: 1.5;
    color: var(--ink-secondary);
    border: 1px solid transparent;
    transition: all var(--transition-fast);
    user-select: none;
}
.quiz__option:hover {
    background: var(--paper-warm);
    border-color: var(--rule);
}
.quiz__option input[type="radio"] {
    appearance: none;
    -webkit-appearance: none;
    width: 14px;
    height: 14px;
    border: 1.5px solid var(--rule-strong);
    border-radius: 50%;
    flex-shrink: 0;
    margin-top: 0.15rem;
    cursor: pointer;
    position: relative;
    transition: all var(--transition-fast);
}
.quiz__option input[type="radio"]:checked {
    border-color: var(--ink);
}
.quiz__option input[type="radio"]:checked::after {
    content: '';
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 6px;
    height: 6px;
    background: var(--ink);
    border-radius: 50%;
}
.quiz__option.correct {
    border-color: #2d8a4e;
    background: rgba(45, 138, 78, 0.05);
}
.quiz__option.correct input[type="radio"]:checked {
    border-color: #2d8a4e;
}
.quiz__option.correct input[type="radio"]:checked::after {
    background: #2d8a4e;
}
.quiz__option.incorrect {
    border-color: #c0392b;
    background: rgba(192, 57, 43, 0.05);
}
.quiz__option.incorrect input[type="radio"]:checked {
    border-color: #c0392b;
}
.quiz__option.incorrect input[type="radio"]:checked::after {
    background: #c0392b;
}
.quiz__feedback {
    display: none;
    margin-top: 0.5rem;
    padding: 0.6rem 0.9rem;
    font-family: var(--serif-body);
    font-size: 0.85rem;
    line-height: 1.6;
    border-left: 2px solid;
}
.quiz__feedback.show { display: block; }
.quiz__feedback.correct {
    border-color: #2d8a4e;
    color: #2d8a4e;
    background: rgba(45, 138, 78, 0.04);
}
.quiz__feedback.incorrect {
    border-color: #c0392b;
    color: #c0392b;
    background: rgba(192, 57, 43, 0.04);
}
.quiz__score {
    margin-top: 1rem;
    padding: 0.75rem 1rem;
    background: var(--paper-warm);
    border: 1px solid var(--rule);
    font-family: var(--sans);
    font-size: 0.75rem;
    font-weight: 600;
    color: var(--ink);
    text-align: center;
    display: none;
}
.quiz__score.show { display: block; }
.quiz__check-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-family: var(--sans);
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.5rem 1.25rem;
    border: 1px solid var(--ink);
    background: var(--ink);
    color: var(--paper);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-top: 0.75rem;
}
.quiz__check-btn:hover {
    background: var(--paper);
    color: var(--ink);
}

/* ---------- FLASHCARDS ---------- */
.flashcards {
    border-top: 2px solid var(--ink);
    border-bottom: 1px solid var(--rule);
    padding: 1.5rem 0;
    margin-top: 2rem;
}
.flashcards__title {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 1rem;
}
.flashcard {
    perspective: 800px;
    height: 180px;
    margin-bottom: 0.75rem;
    cursor: pointer;
}
.flashcard__inner {
    position: relative;
    width: 100%;
    height: 100%;
    transition: transform 0.5s var(--ease);
    transform-style: preserve-3d;
}
.flashcard.flipped .flashcard__inner {
    transform: rotateX(180deg);
}
.flashcard__front,
.flashcard__back {
    position: absolute;
    inset: 0;
    backface-visibility: hidden;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 1.5rem;
    border: 1px solid var(--rule);
    text-align: center;
}
.flashcard__front {
    background: var(--paper-warm);
}
.flashcard__front p {
    font-family: var(--serif-display);
    font-size: var(--text-lg);
    font-weight: 700;
    color: var(--ink);
    line-height: 1.4;
}
.flashcard__back {
    background: var(--ink);
    transform: rotateX(180deg);
}
.flashcard__back p {
    font-family: var(--serif-body);
    font-size: var(--text-base);
    color: var(--paper);
    line-height: 1.6;
}
.flashcard__counter {
    font-family: var(--sans);
    font-size: 0.6rem;
    color: var(--ink-muted);
    font-weight: 600;
    letter-spacing: 0.1em;
    margin-bottom: 0.5rem;
}
.flashcard__nav {
    display: flex;
    gap: 0.5rem;
}
.flashcard__btn {
    font-family: var(--sans);
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 0.4rem 0.85rem;
    border: 1px solid var(--rule-strong);
    background: none;
    color: var(--ink-secondary);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.flashcard__btn:hover {
    border-color: var(--ink);
    color: var(--ink);
}

/* ---------- EXERCISE CHECKER ---------- */
.exercise-check {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    margin-top: 0.5rem;
}
.exercise-check__input {
    font-family: var(--mono);
    font-size: 0.8rem;
    padding: 0.3rem 0.6rem;
    border: 1px solid var(--rule-strong);
    background: var(--paper);
    color: var(--ink);
    width: 120px;
    outline: none;
    transition: border-color var(--transition-fast);
}
.exercise-check__input:focus {
    border-color: var(--ink);
}
.exercise-check__btn {
    font-family: var(--sans);
    font-size: 0.6rem;
    font-weight: 700;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    padding: 0.35rem 0.75rem;
    border: 1px solid var(--ink);
    background: var(--ink);
    color: var(--paper);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.exercise-check__btn:hover {
    background: var(--paper);
    color: var(--ink);
}
.exercise-check__result {
    font-family: var(--sans);
    font-size: 0.7rem;
    font-weight: 600;
}
.exercise-check__result.correct { color: #2d8a4e; }
.exercise-check__result.incorrect { color: #c0392b; }

/* ---------- EXAMPLE ANSWER ---------- */
.example-answer {
    margin-top: 0.75rem;
}
.example-answer__toggle {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
    background: none;
    border: none;
    cursor: pointer;
    padding: 0.25rem 0;
    transition: color var(--transition-fast);
}
.example-answer__toggle:hover { color: var(--ink); }
.example-answer__content {
    display: none;
    margin-top: 0.5rem;
    padding: 0.75rem 1rem;
    background: var(--paper-warm);
    border-left: 2px solid var(--rule-strong);
    font-family: var(--serif-body);
    font-size: 0.88rem;
    line-height: 1.65;
    color: var(--ink-secondary);
    font-style: italic;
}
.example-answer__content.show { display: block; }

/* ---------- SEARCH OVERLAY ---------- */
.search-overlay {
    position: fixed;
    inset: 0;
    z-index: 2000;
    background: rgba(0,0,0,0.5);
    display: none;
    align-items: flex-start;
    justify-content: center;
    padding-top: 15vh;
    backdrop-filter: blur(4px);
}
.search-overlay.open { display: flex; }
.search-box {
    width: 90%;
    max-width: 560px;
    background: var(--paper);
    border: 1px solid var(--rule);
    border-radius: 3px;
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    overflow: hidden;
}
.search-box__input {
    width: 100%;
    padding: 1rem 1.25rem;
    border: none;
    border-bottom: 1px solid var(--rule);
    font-family: var(--sans);
    font-size: 0.9rem;
    background: var(--paper);
    color: var(--ink);
    outline: none;
}
.search-box__input::placeholder { color: var(--ink-faint); }
.search-box__results {
    max-height: 50vh;
    overflow-y: auto;
    padding: 0.5rem;
}
.search-result {
    display: block;
    padding: 0.75rem 1rem;
    border-bottom: 1px solid var(--rule);
    text-decoration: none;
    transition: background var(--transition-fast);
}
.search-result:hover {
    background: var(--paper-warm);
    border-bottom-color: var(--rule);
}
.search-result:last-child { border-bottom: none; }
.search-result__week {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.15em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
}
.search-result__title {
    font-family: var(--serif-display);
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--ink);
    margin: 0.15rem 0;
}
.search-result__excerpt {
    font-family: var(--serif-body);
    font-size: 0.8rem;
    color: var(--ink-secondary);
    line-height: 1.5;
}
.search-empty {
    padding: 2rem;
    text-align: center;
    font-family: var(--sans);
    font-size: 0.8rem;
    color: var(--ink-muted);
}

/* ---------- PRINT BUTTON ---------- */
.print-btn {
    display: inline-flex;
    align-items: center;
    gap: 0.4rem;
    font-family: var(--sans);
    font-size: 0.6rem;
    font-weight: 600;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.4rem 0.85rem;
    border: 1px solid var(--rule-strong);
    background: none;
    color: var(--ink-muted);
    cursor: pointer;
    transition: all var(--transition-fast);
}
.print-btn:hover {
    border-color: var(--ink);
    color: var(--ink);
}

/* ---------- TOOL PAGES ---------- */
.tool-page {
    max-width: var(--max-read);
    margin: 0 auto;
    padding: 0 2rem;
}
.tool-input-group {
    margin-bottom: 1rem;
}
.tool-input-group label {
    display: block;
    font-family: var(--sans);
    font-size: 0.65rem;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
    margin-bottom: 0.35rem;
}
.tool-input-group input {
    width: 100%;
    max-width: 300px;
    font-family: var(--mono);
    font-size: 0.9rem;
    padding: 0.5rem 0.75rem;
    border: 1px solid var(--rule-strong);
    background: var(--paper);
    color: var(--ink);
    outline: none;
    transition: border-color var(--transition-fast);
}
.tool-input-group input:focus { border-color: var(--ink); }
.tool-result {
    margin-top: 1.5rem;
    padding: 1.25rem;
    background: var(--paper-warm);
    border: 1px solid var(--rule);
    border-top: 2px solid var(--ink);
}
.tool-result__title {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 700;
    margin-bottom: 0.75rem;
}
.tool-result__value {
    font-family: var(--mono);
    font-size: 1.2rem;
    font-weight: 700;
    color: var(--ink);
    margin-bottom: 0.5rem;
}
.tool-result__steps {
    font-family: var(--serif-body);
    font-size: 0.9rem;
    line-height: 1.7;
    color: var(--ink-secondary);
}
.tool-result__steps p {
    margin-bottom: 0.5rem;
}
.tool-calc-btn {
    font-family: var(--sans);
    font-size: 0.65rem;
    font-weight: 700;
    letter-spacing: 0.12em;
    text-transform: uppercase;
    padding: 0.6rem 1.5rem;
    border: 1px solid var(--ink);
    background: var(--ink);
    color: var(--paper);
    cursor: pointer;
    transition: all var(--transition-fast);
    margin-top: 0.5rem;
}
.tool-calc-btn:hover {
    background: var(--paper);
    color: var(--ink);
}

/* ---------- CONFUSION MATRIX VISUAL ---------- */
.cm-grid {
    display: grid;
    grid-template-columns: auto 1fr 1fr;
    grid-template-rows: auto 1fr 1fr;
    gap: 2px;
    max-width: 400px;
    margin: 1rem 0;
}
.cm-header {
    font-family: var(--sans);
    font-size: 0.6rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    font-weight: 700;
    color: var(--ink-muted);
    padding: 0.5rem;
    text-align: center;
}
.cm-cell {
    padding: 1rem;
    text-align: center;
    border: 1px solid var(--rule);
    background: var(--paper-warm);
    min-height: 80px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}
.cm-cell__label {
    font-family: var(--sans);
    font-size: 0.55rem;
    letter-spacing: 0.1em;
    text-transform: uppercase;
    color: var(--ink-muted);
    font-weight: 600;
    margin-bottom: 0.25rem;
}
.cm-cell__value {
    font-family: var(--serif-display);
    font-size: 1.5rem;
    font-weight: 900;
    color: var(--ink);
}
.cm-cell.tp { background: rgba(45, 138, 78, 0.08); }
.cm-cell.tn { background: rgba(45, 138, 78, 0.04); }
.cm-cell.fp { background: rgba(192, 57, 43, 0.06); }
.cm-cell.fn { background: rgba(192, 57, 43, 0.08); }

/* ---------- LOSS CHART ---------- */
.loss-chart {
    width: 100%;
    max-width: 500px;
    margin: 1rem 0;
}
.loss-chart svg {
    width: 100%;
    height: auto;
}

/* ---------- RESPONSIVE ADDITIONS ---------- */
@media (max-width: 768px) {
    .mini-toc {
        float: none;
        width: 100%;
        margin-left: 0;
        position: static;
        margin-bottom: 1.5rem;
    }
    .search-overlay { padding-top: 5vh; }
    .search-box { width: 95%; }
    .cm-grid { max-width: 100%; }
}

@media (max-width: 480px) {
    .flashcard { height: 200px; }
    .quiz__option { padding: 0.4rem 0.5rem; font-size: 0.85rem; }
}

/* ---------- PRINT ---------- */
@media print {
    .nav, .hero__scroll, .hero__cta, .week-nav, .footer { display: none; }
    body { background: white; color: black; font-size: 12pt; }
    .page-hero { padding-top: 2rem; }
    .session-card { break-inside: avoid; }
}