/* ======================================================================
   AIGP Interactive Study Guide — Styles
   Font: Optimistic (Meta) with Inter fallback
   ====================================================================== */

@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
    /* Base palette */
    --bg: #0b1020;
    --bg-elev: #151b2e;
    --bg-elev-2: #1c2340;
    --bg-deep: #060912;
    --border: #2a3454;
    --border-soft: #1f2840;
    --text: #e6e9f5;
    --text-dim: #9aa3c0;
    --text-faint: #6b7494;

    /* Accent palette */
    --blue: #5b8def;
    --indigo: #7c6cf7;
    --violet: #a78bfa;
    --pink: #ec4899;
    --rose: #f43f5e;
    --orange: #fb923c;
    --amber: #fbbf24;
    --gold: #f59e0b;
    --green: #34d399;
    --emerald: #10b981;
    --teal: #2dd4bf;
    --cyan: #22d3ee;
    --red: #f87171;

    /* Per-domain accent (4-domain BoK: lessons & decks) */
    --d1: #5b8def;   /* I  — Foundations of AI Governance — blue */
    --d2: #fbbf24;   /* II — Laws, Standards & Frameworks — amber */
    --d3: #a78bfa;   /* III — Governing AI Development — violet */
    --d4: #ec4899;   /* IV — Governing AI Deployment & Use — pink */

    /* Competency sub-accents (lighter shades) */
    --c-a: #5b8def;
    --c-b: #2dd4bf;
    --c-c: #fb923c;
    --c-d: #ec4899;
}

* { margin: 0; padding: 0; box-sizing: border-box; }

body {
    font-family: 'Optimistic Display', 'Optimistic Text', 'Optimistic', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background:
        radial-gradient(1100px 700px at 10% -5%, rgba(91, 141, 239, 0.12), transparent 60%),
        radial-gradient(900px 600px at 110% 5%, rgba(167, 139, 250, 0.10), transparent 55%),
        radial-gradient(800px 600px at 50% 110%, rgba(45, 212, 191, 0.08), transparent 60%),
        var(--bg);
    color: var(--text);
    line-height: 1.6;
    min-height: 100vh;
}

.container { max-width: 1200px; margin: 0 auto; padding: 24px 20px 60px; }

h1 {
    text-align: center;
    font-size: 2.4rem;
    font-weight: 800;
    letter-spacing: -0.02em;
    margin-bottom: 8px;
    background: linear-gradient(135deg, var(--blue), var(--violet) 50%, var(--pink));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.subtitle {
    text-align: center;
    color: var(--text-dim);
    margin-bottom: 28px;
    font-size: 1rem;
    font-weight: 500;
}

/* Tabs */
.tabs { display: flex; gap: 6px; margin-bottom: 22px; flex-wrap: wrap; justify-content: center; }
.tab {
    padding: 11px 20px;
    background: rgba(28, 35, 64, 0.7);
    border: 1px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    transition: all 0.18s;
    font-size: 0.88rem;
    font-weight: 500;
    backdrop-filter: blur(6px);
}
.tab:hover { background: var(--bg-elev-2); border-color: var(--blue); transform: translateY(-1px); }
.tab.active {
    background: linear-gradient(135deg, var(--blue), var(--indigo));
    border-color: transparent;
    color: white;
    box-shadow: 0 6px 20px -6px rgba(91, 141, 239, 0.6);
}

/* Progress */
.progress-bar {
    background: var(--bg-elev);
    border-radius: 14px;
    height: 26px;
    margin-bottom: 24px;
    overflow: hidden;
    border: 1px solid var(--border);
    position: relative;
}
.progress-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--blue), var(--violet) 50%, var(--pink));
    transition: width 0.5s;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.78rem;
    font-weight: 700;
    color: white;
    text-shadow: 0 1px 2px rgba(0,0,0,0.3);
}

/* Content panels */
.panel { display: none; animation: fadeIn 0.25s ease; }
.panel.active { display: block; }
@keyframes fadeIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* Domain cards (study guide) */
.domain-card {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 14px;
    margin-bottom: 16px;
    overflow: hidden;
    transition: border-color 0.2s;
}
.domain-card:hover { border-color: var(--border); }
.domain-header {
    padding: 18px 22px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    border-left: 4px solid var(--blue);
}
.domain-header:hover { background: var(--bg-elev-2); }
.domain-title { font-weight: 600; font-size: 1.08rem; }
.domain-badge {
    background: linear-gradient(135deg, var(--blue), var(--indigo));
    padding: 3px 12px;
    border-radius: 14px;
    font-size: 0.75rem;
    font-weight: 600;
    color: white;
}
.domain-content { padding: 0 22px 22px; display: none; }
.domain-content.open { display: block; }

/* Per-domain accent stripe in study guide */
.domain-card[data-domain="1"] .domain-header { border-left-color: var(--d1); }
.domain-card[data-domain="2"] .domain-header { border-left-color: var(--d2); }
.domain-card[data-domain="3"] .domain-header { border-left-color: var(--d3); }
.domain-card[data-domain="4"] .domain-header { border-left-color: var(--d4); }

/* Competency sub-heading inside domain */
.competency-header {
    margin: 22px 0 10px;
    padding: 10px 14px;
    background: linear-gradient(135deg, rgba(91,141,239,0.10), rgba(167,139,250,0.06));
    border-left: 3px solid var(--blue);
    border-radius: 8px;
    color: var(--text);
}
.competency-header .competency-id {
    font-family: 'SF Mono', Menlo, Consolas, monospace;
    font-size: 0.78rem;
    background: rgba(91,141,239,0.18);
    color: var(--blue);
    padding: 2px 8px;
    border-radius: 6px;
    font-weight: 700;
    margin-right: 10px;
}
.competency-header .competency-title {
    font-weight: 600;
    font-size: 0.98rem;
}
.competency-header .competency-meta {
    color: var(--text-faint);
    font-size: 0.78rem;
    margin-left: 10px;
    font-style: italic;
}
.competency-header:first-child { margin-top: 4px; }

/* Topics */
.topic { background: var(--bg-deep); border: 1px solid var(--border); border-radius: 10px; padding: 14px 16px; margin-bottom: 10px; }
.topic-header { display: flex; align-items: flex-start; gap: 10px; cursor: pointer; }
.topic-check { width: 22px; height: 22px; border: 2px solid #475569; border-radius: 6px; flex-shrink: 0; display: flex; align-items: center; justify-content: center; transition: all 0.2s; margin-top: 2px; }
.topic-check.checked { background: var(--green); border-color: var(--green); }
.topic-check.checked::after { content: '\2713'; color: white; font-size: 13px; font-weight: bold; }
.topic-title { font-weight: 500; flex: 1; }
.topic-details { margin-top: 12px; padding-left: 32px; color: var(--text-dim); font-size: 0.92rem; }
.topic-details ul { padding-left: 18px; }
.topic-details li { margin-bottom: 6px; }
.topic-details .highlight { color: var(--amber); font-weight: 600; }
.topic-details .key-term { color: var(--blue); font-weight: 600; }

/* Flashcards */
.flashcard-container { display: flex; flex-direction: column; align-items: center; gap: 22px; }
.flashcard {
    width: 100%;
    max-width: 640px;
    min-height: 280px;
    background: linear-gradient(135deg, var(--bg-elev), var(--bg-elev-2));
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 36px;
    display: flex;
    align-items: center;
    justify-content: center;
    text-align: center;
    cursor: pointer;
    transition: transform 0.3s, box-shadow 0.3s;
    position: relative;
    box-shadow: 0 12px 40px -12px rgba(0,0,0,0.5);
}
.flashcard:hover { transform: scale(1.02); box-shadow: 0 18px 50px -12px rgba(91, 141, 239, 0.4); }
.flashcard-label { position: absolute; top: 14px; left: 18px; font-size: 0.7rem; color: var(--text-faint); text-transform: uppercase; letter-spacing: 1.5px; font-weight: 600; }
.flashcard-text { font-size: 1.15rem; line-height: 1.5; }
.flashcard-nav { display: flex; gap: 12px; flex-wrap: wrap; justify-content: center; }
.flashcard-btn {
    padding: 11px 26px;
    background: linear-gradient(135deg, var(--blue), var(--indigo));
    border: none;
    color: white;
    border-radius: 10px;
    cursor: pointer;
    font-size: 0.9rem;
    font-weight: 600;
    font-family: inherit;
    transition: all 0.2s;
}
.flashcard-btn:hover { opacity: 0.92; transform: translateY(-1px); }
.flashcard-btn.secondary { background: var(--bg-elev-2); border: 1px solid var(--border); }
.flashcard-counter { color: var(--text-faint); font-size: 0.85rem; }
.flashcard-domain-filter { margin-bottom: 18px; display: flex; gap: 8px; flex-wrap: wrap; justify-content: center; }
.filter-btn { padding: 7px 14px; background: var(--bg-elev); border: 1px solid var(--border); border-radius: 8px; cursor: pointer; font-size: 0.82rem; color: var(--text-dim); font-family: inherit; transition: all 0.2s; }
.filter-btn:hover { color: var(--text); border-color: var(--blue); }
.filter-btn.active { background: linear-gradient(135deg, var(--blue), var(--indigo)); border-color: transparent; color: white; }

/* Schedule */
.schedule-config { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 14px; padding: 22px; margin-bottom: 20px; }
.config-row { display: flex; gap: 16px; align-items: center; flex-wrap: wrap; margin-bottom: 14px; }
.config-label { font-size: 0.88rem; color: var(--text-dim); min-width: 130px; font-weight: 500; }
.config-input { background: var(--bg-deep); border: 1px solid var(--border); border-radius: 8px; padding: 9px 14px; color: var(--text); font-size: 0.9rem; font-family: inherit; }
.config-input:focus { outline: none; border-color: var(--blue); box-shadow: 0 0 0 3px rgba(91, 141, 239, 0.15); }
select.config-input { cursor: pointer; }
.generate-btn { padding: 11px 26px; background: linear-gradient(135deg, var(--blue), var(--violet) 50%, var(--pink)); border: none; color: white; border-radius: 10px; cursor: pointer; font-weight: 600; font-size: 0.92rem; font-family: inherit; box-shadow: 0 6px 20px -6px rgba(167, 139, 250, 0.5); transition: all 0.2s; }
.generate-btn:hover { transform: translateY(-1px); }

.schedule-week { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 14px; margin-bottom: 16px; overflow: hidden; }
.week-header { padding: 14px 22px; background: linear-gradient(90deg, var(--bg-elev-2), var(--bg-elev)); font-weight: 600; display: flex; justify-content: space-between; }
.week-day { padding: 12px 22px; border-top: 1px solid var(--border); display: flex; justify-content: space-between; align-items: center; }
.day-label { font-weight: 600; min-width: 80px; color: var(--blue); }
.day-content { color: var(--text-dim); font-size: 0.92rem; flex: 1; }
.day-time { color: var(--violet); font-size: 0.82rem; white-space: nowrap; font-weight: 600; }

/* Quiz */
.quiz-question { background: var(--bg-elev); border: 1px solid var(--border); border-radius: 14px; padding: 24px; margin-bottom: 16px; }
.quiz-q { font-weight: 600; margin-bottom: 18px; font-size: 1.05rem; }
.quiz-option { padding: 13px 18px; background: var(--bg-deep); border: 1px solid var(--border); border-radius: 10px; margin-bottom: 8px; cursor: pointer; transition: all 0.2s; }
.quiz-option:hover { border-color: var(--blue); transform: translateX(2px); }
.quiz-option.correct { background: rgba(52, 211, 153, 0.15); border-color: var(--green); color: #6ee7b7; }
.quiz-option.incorrect { background: rgba(248, 113, 113, 0.12); border-color: var(--red); color: #fca5a5; }
.quiz-option.disabled { pointer-events: none; }
.quiz-explanation { margin-top: 14px; padding: 14px; background: var(--bg-deep); border-radius: 10px; color: var(--text-dim); font-size: 0.92rem; display: none; border-left: 3px solid var(--blue); }
.quiz-score { text-align: center; padding: 26px; background: linear-gradient(135deg, var(--bg-elev), var(--bg-elev-2)); border-radius: 14px; margin-bottom: 22px; border: 1px solid var(--border); }
.quiz-score-num { font-size: 2.8rem; font-weight: 800; background: linear-gradient(135deg, var(--green), var(--blue)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.quiz-controls { display: flex; gap: 12px; justify-content: center; margin-bottom: 22px; flex-wrap: wrap; }

/* Stats */
.stats-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(200px, 1fr)); gap: 16px; margin-bottom: 22px; }
.stat-card { background: linear-gradient(135deg, var(--bg-elev), var(--bg-elev-2)); border: 1px solid var(--border); border-radius: 14px; padding: 22px; text-align: center; transition: transform 0.2s; }
.stat-card:hover { transform: translateY(-3px); }
.stat-num { font-size: 2.2rem; font-weight: 800; background: linear-gradient(135deg, var(--blue), var(--violet)); -webkit-background-clip: text; -webkit-text-fill-color: transparent; }
.stat-label { font-size: 0.82rem; color: var(--text-faint); margin-top: 4px; font-weight: 500; }

/* ======================================================================
   LESSONS
   ====================================================================== */

.lesson-domain-nav { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 22px; justify-content: center; }
.lesson-domain-btn {
    padding: 9px 16px;
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 10px;
    cursor: pointer;
    color: var(--text-dim);
    font-size: 0.86rem;
    font-weight: 500;
    font-family: inherit;
    transition: all 0.2s;
}
.lesson-domain-btn:hover { background: var(--bg-elev-2); color: var(--text); }
.lesson-domain-btn.active { background: linear-gradient(135deg, var(--blue), var(--indigo)); border-color: transparent; color: white; box-shadow: 0 6px 18px -6px rgba(91, 141, 239, 0.5); }
.lesson-domain-btn.locked { opacity: 0.4; cursor: not-allowed; }
.lesson-domain-btn[data-domain="1"].active { background: linear-gradient(135deg, var(--d1), #4a7bd9); }
.lesson-domain-btn[data-domain="2"].active { background: linear-gradient(135deg, var(--d2), var(--gold)); color: #1a1300; }
.lesson-domain-btn[data-domain="3"].active { background: linear-gradient(135deg, var(--d3), var(--violet)); }
.lesson-domain-btn[data-domain="4"].active { background: linear-gradient(135deg, var(--d4), #db2777); }

.lesson-header {
    background: linear-gradient(135deg, var(--bg-elev), var(--bg-elev-2));
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 28px;
    margin-bottom: 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    position: relative;
    overflow: hidden;
}
.lesson-header::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 4px;
    background: linear-gradient(90deg, var(--blue), var(--violet));
}
.lesson-header[data-domain="1"]::before { background: linear-gradient(90deg, var(--d1), #818cf8); }
.lesson-header[data-domain="2"]::before { background: linear-gradient(90deg, var(--d2), var(--orange)); }
.lesson-header[data-domain="3"]::before { background: linear-gradient(90deg, var(--d3), var(--violet)); }
.lesson-header[data-domain="4"]::before { background: linear-gradient(90deg, var(--d4), var(--rose)); }

.lesson-header-text h2 {
    font-size: 1.55rem;
    font-weight: 700;
    margin-bottom: 8px;
    letter-spacing: -0.01em;
    background: linear-gradient(135deg, var(--blue), var(--violet));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}
.lesson-header-text p { color: var(--text-dim); font-size: 0.95rem; max-width: 660px; }

.present-btn {
    padding: 13px 26px;
    background: linear-gradient(135deg, var(--blue), var(--violet) 50%, var(--pink));
    border: none;
    color: white;
    border-radius: 12px;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    font-family: inherit;
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
    box-shadow: 0 8px 24px -6px rgba(167, 139, 250, 0.45);
    transition: all 0.2s;
}
.present-btn:hover { transform: translateY(-2px); box-shadow: 0 12px 28px -6px rgba(167, 139, 250, 0.55); }
.present-btn::before { content: '▶'; font-size: 0.8rem; }

.lesson-topic {
    background: var(--bg-elev);
    border: 1px solid var(--border);
    border-radius: 14px;
    margin-bottom: 14px;
    overflow: hidden;
    transition: border-color 0.2s;
}
.lesson-topic:hover { border-color: var(--border); }
.lesson-topic-header { padding: 18px 22px; cursor: pointer; display: flex; justify-content: space-between; align-items: center; }
.lesson-topic-header:hover { background: var(--bg-elev-2); }
.lesson-topic-title { font-weight: 600; font-size: 1.05rem; }
.lesson-topic-id {
    color: var(--blue);
    font-size: 0.78rem;
    font-family: 'SF Mono', Menlo, Consolas, monospace;
    margin-right: 12px;
    background: rgba(91, 141, 239, 0.12);
    padding: 2px 8px;
    border-radius: 6px;
    font-weight: 600;
}
.lesson-topic-toggle { color: var(--text-faint); font-size: 1.4rem; transition: transform 0.2s; }
.lesson-topic.open .lesson-topic-toggle { transform: rotate(90deg); color: var(--blue); }
.lesson-topic-body { padding: 0 22px 24px; display: none; }
.lesson-topic.open .lesson-topic-body { display: block; }

.lesson-section { margin-top: 20px; padding-top: 20px; border-top: 1px solid var(--border-soft); }
.lesson-section:first-child { border-top: none; padding-top: 4px; }
.lesson-section h4 {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 12px;
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 4px 10px;
    border-radius: 6px;
}
.lesson-section[data-section-type="concept"] h4 { color: var(--blue); background: rgba(91, 141, 239, 0.12); }
.lesson-section[data-section-type="why"] h4 { color: var(--orange); background: rgba(251, 146, 60, 0.12); }
.lesson-section[data-section-type="examples"] h4 { color: var(--green); background: rgba(52, 211, 153, 0.12); }
.lesson-section[data-section-type="traps"] h4 { color: var(--red); background: rgba(248, 113, 113, 0.12); }
.lesson-section[data-section-type="mnemonic"] h4 { color: var(--amber); background: rgba(251, 191, 36, 0.12); }
.lesson-section[data-section-type="diagram"] h4 { color: var(--violet); background: rgba(167, 139, 250, 0.12); }

.lesson-section p { color: #cbd5e1; margin-bottom: 12px; font-size: 0.96rem; }
.lesson-section ul { padding-left: 22px; color: #cbd5e1; font-size: 0.96rem; }
.lesson-section li { margin-bottom: 8px; }
.lesson-section .key-term { color: var(--blue); font-weight: 600; }
.lesson-section .highlight { color: var(--amber); font-weight: 600; }
.lesson-section .trap { color: var(--red); font-weight: 600; }
.lesson-section .good { color: var(--green); font-weight: 600; }
.lesson-section .mnemonic {
    background: linear-gradient(135deg, rgba(251, 191, 36, 0.08), rgba(251, 146, 60, 0.06));
    border-left: 4px solid var(--amber);
    padding: 14px 18px;
    border-radius: 8px;
    color: #fde68a;
    font-size: 1rem;
    font-weight: 500;
}

.lesson-sources {
    margin-top: 22px;
    padding: 16px 20px;
    background: var(--bg-deep);
    border-radius: 10px;
    border: 1px solid var(--border-soft);
}
.lesson-sources h5 {
    color: var(--text-faint);
    font-size: 0.72rem;
    text-transform: uppercase;
    letter-spacing: 1.5px;
    margin-bottom: 10px;
    font-weight: 700;
}
.lesson-sources ul { list-style: none; padding-left: 0; }
.lesson-sources li { font-size: 0.86rem; margin-bottom: 6px; padding-left: 18px; position: relative; }
.lesson-sources li::before { content: '↗'; color: var(--blue); position: absolute; left: 0; font-weight: 700; }
.lesson-sources a { color: var(--blue); text-decoration: none; transition: color 0.2s; }
.lesson-sources a:hover { color: var(--violet); text-decoration: underline; }
.lesson-sources .no-link { color: var(--text-dim); }
.lesson-sources li.no-link::before { content: '•'; color: var(--text-faint); }

.lesson-coming-soon { padding: 80px 24px; text-align: center; background: var(--bg-elev); border-radius: 16px; border: 1px dashed var(--border); color: var(--text-faint); }
.lesson-coming-soon h3 { color: var(--text-dim); margin-bottom: 10px; font-weight: 600; }

/* SVG diagrams inside lesson sections */
.diagram-wrap {
    margin: 16px 0 8px;
    padding: 20px;
    background: var(--bg-deep);
    border: 1px solid var(--border-soft);
    border-radius: 12px;
    text-align: center;
}
.diagram-wrap svg { max-width: 100%; height: auto; }
.diagram-caption { color: var(--text-faint); font-size: 0.82rem; margin-top: 10px; font-style: italic; }

/* Inline pill labels */
.pill { display: inline-block; padding: 2px 10px; border-radius: 12px; font-size: 0.78rem; font-weight: 600; margin: 0 2px; }
.pill.blue { background: rgba(91,141,239,0.15); color: var(--blue); }
.pill.green { background: rgba(52,211,153,0.15); color: var(--green); }
.pill.amber { background: rgba(251,191,36,0.15); color: var(--amber); }
.pill.red { background: rgba(248,113,113,0.15); color: var(--red); }
.pill.violet { background: rgba(167,139,250,0.15); color: var(--violet); }
.pill.pink { background: rgba(236,72,153,0.15); color: var(--pink); }

/* ======================================================================
   SLIDE DECK
   ====================================================================== */

.slide-overlay { display: none; position: fixed; top: 0; left: 0; width: 100vw; height: 100vh; background: var(--bg-deep); z-index: 1000; flex-direction: column; }
.slide-overlay.active { display: flex; }

.slide-topbar { display: flex; justify-content: space-between; align-items: center; padding: 14px 26px; background: rgba(11, 16, 32, 0.96); border-bottom: 1px solid var(--border); backdrop-filter: blur(8px); }
.slide-title-bar { color: var(--text-dim); font-size: 0.92rem; font-weight: 500; }
.slide-controls { display: flex; gap: 8px; align-items: center; }
.slide-counter { color: var(--text-faint); font-size: 0.85rem; margin-right: 14px; font-weight: 500; }
.slide-btn { padding: 9px 16px; background: var(--bg-elev); border: 1px solid var(--border); color: var(--text); border-radius: 8px; cursor: pointer; font-size: 0.85rem; font-weight: 500; font-family: inherit; transition: all 0.2s; }
.slide-btn:hover { background: var(--bg-elev-2); border-color: var(--blue); }
.slide-btn.close { background: linear-gradient(135deg, #b91c1c, #7f1d1d); border-color: transparent; }
.slide-btn.close:hover { background: linear-gradient(135deg, #dc2626, #991b1b); }

.slide-stage { flex: 1; display: flex; align-items: center; justify-content: center; padding: 40px; overflow-y: auto; }
.slide {
    width: 100%;
    max-width: 1040px;
    min-height: 540px;
    padding: 56px 64px;
    background: linear-gradient(135deg, var(--bg-elev), var(--bg-elev-2));
    border: 1px solid var(--border);
    border-radius: 20px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    position: relative;
    box-shadow: 0 30px 80px -20px rgba(0,0,0,0.6);
}
.slide::before {
    content: '';
    position: absolute;
    top: 0; left: 0; right: 0; height: 5px;
    border-radius: 20px 20px 0 0;
    background: linear-gradient(90deg, var(--blue), var(--violet) 50%, var(--pink));
}
.slide[data-domain="1"]::before { background: linear-gradient(90deg, var(--d1), #818cf8); }
.slide[data-domain="2"]::before { background: linear-gradient(90deg, var(--d2), var(--orange)); }
.slide[data-domain="3"]::before { background: linear-gradient(90deg, var(--d3), var(--violet)); }
.slide[data-domain="4"]::before { background: linear-gradient(90deg, var(--d4), var(--rose)); }

.slide.title-slide {
    text-align: center;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--bg-elev), #312e81);
}
.slide.title-slide h1 {
    font-size: 3.4rem;
    margin-bottom: 18px;
    background: linear-gradient(135deg, var(--blue), var(--violet) 50%, var(--pink));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-weight: 800;
    letter-spacing: -0.03em;
}
.slide.title-slide .subtitle { color: #cbd5e1; font-size: 1.45rem; margin-bottom: 8px; font-weight: 500; }
.slide.title-slide .meta { color: var(--text-faint); font-size: 0.95rem; margin-top: 32px; }

.slide.content-slide h2 {
    font-size: 1.95rem;
    margin-bottom: 26px;
    color: var(--blue);
    border-bottom: 2px solid var(--border);
    padding-bottom: 14px;
    font-weight: 700;
    letter-spacing: -0.01em;
}
.slide[data-domain="2"].content-slide h2 { color: var(--d2); }
.slide[data-domain="3"].content-slide h2 { color: var(--d3); }
.slide[data-domain="4"].content-slide h2 { color: var(--d4); }

.slide.content-slide h3 { font-size: 1.25rem; color: var(--violet); margin-bottom: 16px; margin-top: 14px; font-weight: 600; }
.slide.content-slide ul { padding-left: 26px; }
.slide.content-slide li { font-size: 1.12rem; line-height: 1.85; margin-bottom: 12px; color: var(--text); }
.slide.content-slide .key-term { color: var(--blue); font-weight: 700; }
.slide.content-slide .highlight { color: var(--amber); font-weight: 700; }
.slide.content-slide .footnote { margin-top: auto; padding-top: 22px; color: var(--text-faint); font-size: 0.82rem; font-style: italic; }
.slide.content-slide .mnemonic {
    background: linear-gradient(135deg, rgba(251, 191, 36, 0.12), rgba(251, 146, 60, 0.08));
    border-left: 5px solid var(--amber);
    padding: 18px 22px;
    border-radius: 8px;
    color: #fde68a;
    font-size: 1.15rem;
    font-weight: 500;
    margin-top: 18px;
}
.slide.content-slide .slide-diagram { margin: 18px 0; text-align: center; }
.slide.content-slide .slide-diagram svg { max-width: 100%; height: auto; max-height: 320px; }

.slide.takeaway-slide { background: linear-gradient(135deg, #064e3b, var(--bg-elev-2)); }
.slide.takeaway-slide h2 { color: #4ade80; }

.slide-progress { height: 4px; background: var(--bg-elev); }
.slide-progress-fill { height: 100%; background: linear-gradient(90deg, var(--blue), var(--violet) 50%, var(--pink)); transition: width 0.3s; }

@media (max-width: 768px) {
    .tabs { gap: 4px; }
    .tab { padding: 9px 14px; font-size: 0.78rem; }
    .config-row { flex-direction: column; align-items: flex-start; }
    .slide { padding: 28px; min-height: 420px; }
    .slide.title-slide h1 { font-size: 2.2rem; }
    .slide.content-slide h2 { font-size: 1.5rem; }
    .slide.content-slide li { font-size: 0.98rem; }
    h1 { font-size: 1.85rem; }
    .lesson-header { padding: 20px; }
}