/* ══════════════════════════════════════════════════════════
   Week 6 — Operational Amplifiers slide deck
   Shared styles for individual slide pages + presenter hub
   ══════════════════════════════════════════════════════════ */

:root {
    --slide-bg: #0a0e14;
    --slide-surface: rgba(16, 20, 28, 0.92);
    --slide-border: rgba(255, 255, 255, 0.07);
    --slide-border-hover: rgba(255, 255, 255, 0.18);
    --slide-text: #e2e8f0;
    --slide-text-dim: #8892a4;
    --slide-text-muted: #505868;
    --slide-accent: #6aaa8e;
    --slide-yellow: #ffcc44;
    --slide-red: #e06050;
    --slide-blue: #5a8dee;
    --slide-magenta: #d070d0;
    --slide-cyan: #58c0d8;
}

[data-theme="light"] {
    --slide-bg: #f5f5f7;
    --slide-surface: rgba(255, 255, 255, 0.92);
    --slide-border: rgba(0, 0, 0, 0.1);
    --slide-border-hover: rgba(0, 0, 0, 0.2);
    --slide-text: #1a1a1e;
    --slide-text-dim: #555555;
    --slide-text-muted: #888888;
    --slide-accent: #3d8b6e;
    --slide-yellow: #b8860b;
}

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

html, body {
    font-family: 'IBM Plex Sans', -apple-system, sans-serif;
    background: var(--slide-bg);
    color: var(--slide-text);
    min-height: 100vh;
}

/* ─────────── Individual slide page ─────────── */
body.slide {
    display: flex;
    flex-direction: column;
    padding: 48px 56px 32px;
    gap: 20px;
    min-height: 100vh;
}

.slide-header {
    display: flex;
    flex-direction: column;
    gap: 6px;
    max-width: 1400px;
    margin: 0 auto;
    width: 100%;
}

.slide-header .slide-num {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    letter-spacing: 2px;
    color: var(--slide-accent);
    text-transform: uppercase;
}

.slide-header h1 {
    font-size: 28px;
    font-weight: 700;
    color: var(--slide-text);
    letter-spacing: -0.4px;
}

.slide-header .slide-sub {
    font-size: 14px;
    color: var(--slide-text-dim);
    line-height: 1.5;
}

.manim-stage {
    max-width: 1400px;
    max-height: 800px;
    width: 100%;
    margin: 0 auto;
    background: var(--slide-bg);
    border: 1px solid var(--slide-border);
    border-radius: 10px;
    overflow: hidden;
    position: relative;
    aspect-ratio: 16 / 9;
}

.manim-stage > canvas {
    display: block;
    width: 100%;
    height: 100%;
}

.manim-stage .stage-fallback {
    position: absolute;
    inset: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--slide-text-muted);
    font-family: 'IBM Plex Mono', monospace;
    font-size: 13px;
    text-align: center;
    padding: 16px;
}

.slide-notes {
    max-width: 1040px;
    width: 100%;
    margin: 0 auto;
    background: var(--slide-surface);
    border: 1px solid var(--slide-border);
    border-radius: 8px;
    padding: 14px 20px;
}

.slide-notes ul {
    list-style: none;
    display: grid;
    gap: 8px;
}

.slide-notes li {
    font-size: 13px;
    color: var(--slide-text-dim);
    line-height: 1.6;
    padding-left: 18px;
    position: relative;
}

.slide-notes li::before {
    content: '▸';
    position: absolute;
    left: 0;
    color: var(--slide-accent);
}

.slide-notes .callout {
    grid-column: 1 / -1;
    margin-top: 6px;
    padding: 8px 12px;
    background: rgba(106, 170, 142, 0.08);
    border-left: 2px solid var(--slide-accent);
    border-radius: 4px;
    font-size: 12px;
    color: var(--slide-text);
    font-family: 'IBM Plex Mono', monospace;
}

/* ─────────── Quiz buttons (slide 13) ─────────── */
.quiz-row {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
    margin-top: 10px;
}

.quiz-btn {
    background: var(--slide-surface);
    color: var(--slide-text-dim);
    border: 1px solid var(--slide-border);
    border-radius: 6px;
    padding: 8px 14px;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.15s;
}

.quiz-btn:hover {
    color: var(--slide-text);
    border-color: var(--slide-border-hover);
}

.quiz-btn.active {
    color: var(--slide-accent);
    border-color: var(--slide-accent);
    background: rgba(106, 170, 142, 0.1);
}

/* ─────────── Stepper controls (slide 8) ─────────── */
.stepper-row {
    position: absolute;
    left: 50%;
    bottom: 10px;
    transform: translateX(-50%);
    z-index: 8;
    width: calc(100% - 24px);
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

.stepper-btn {
    background: var(--slide-surface);
    color: var(--slide-text-dim);
    border: 1px solid var(--slide-border);
    border-radius: 6px;
    padding: 8px 14px;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.15s;
}

.stepper-btn:hover:not(:disabled) {
    color: var(--slide-text);
    border-color: var(--slide-border-hover);
}

.stepper-btn:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.step-indicator {
    min-width: 260px;
    text-align: center;
    color: var(--slide-accent);
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    letter-spacing: 0.2px;
}

/* ─────────── Presenter hub page ─────────── */
body.presenter {
    display: grid;
    grid-template-columns: 260px 1fr;
    grid-template-rows: 1fr;
    height: 100vh;
    padding: 0;
}

.deck-sidebar {
    background: var(--slide-surface);
    border-right: 1px solid var(--slide-border);
    overflow-y: auto;
    padding: 64px 0 16px;
}

.deck-sidebar h2 {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    font-weight: 500;
    color: var(--slide-accent);
    letter-spacing: 2px;
    text-transform: uppercase;
    padding: 0 20px 12px;
    border-bottom: 1px solid var(--slide-border);
    margin-bottom: 8px;
}

.deck-sidebar ol {
    list-style: none;
}

.deck-sidebar li {
    border-bottom: 1px solid var(--slide-border);
}

.deck-sidebar li button {
    display: flex;
    align-items: baseline;
    gap: 10px;
    width: 100%;
    background: none;
    border: none;
    color: var(--slide-text-dim);
    padding: 10px 20px;
    text-align: left;
    cursor: pointer;
    font-family: 'IBM Plex Sans', sans-serif;
    font-size: 13px;
    line-height: 1.4;
    transition: all 0.15s;
}

.deck-sidebar li button:hover {
    background: rgba(106, 170, 142, 0.06);
    color: var(--slide-text);
}

.deck-sidebar li.active button {
    background: rgba(106, 170, 142, 0.12);
    color: var(--slide-accent);
    border-left: 2px solid var(--slide-accent);
    padding-left: 18px;
}

.deck-sidebar .deck-num {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 11px;
    color: var(--slide-text-muted);
    min-width: 22px;
}

.deck-main {
    display: flex;
    flex-direction: column;
    position: relative;
}

.slide-frame {
    flex: 1;
    width: 100%;
    border: none;
    background: var(--slide-bg);
}

.deck-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    padding: 12px 20px;
    background: var(--slide-surface);
    border-top: 1px solid var(--slide-border);
}

.deck-controls button {
    background: none;
    border: 1px solid var(--slide-border);
    border-radius: 6px;
    color: var(--slide-text-dim);
    padding: 8px 18px;
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    cursor: pointer;
    transition: all 0.15s;
}

.deck-controls button:hover:not(:disabled) {
    color: var(--slide-text);
    border-color: var(--slide-border-hover);
    background: rgba(255, 255, 255, 0.03);
}

.deck-controls button:disabled {
    opacity: 0.35;
    cursor: not-allowed;
}

.deck-controls .deck-counter {
    font-family: 'IBM Plex Mono', monospace;
    font-size: 12px;
    color: var(--slide-text-muted);
    min-width: 64px;
    text-align: center;
}

.back-btn {
    position: fixed;
    top: 12px;
    left: 12px;
    z-index: 100;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: 6px;
    background: var(--slide-surface);
    border: 1px solid var(--slide-border);
    color: var(--slide-text-dim);
    text-decoration: none;
    font-size: 12px;
    font-weight: 500;
    font-family: 'IBM Plex Mono', monospace;
    backdrop-filter: blur(8px);
    transition: all 0.15s;
}

.back-btn:hover {
    color: var(--slide-text);
    border-color: var(--slide-border-hover);
}

/* Narrow viewport */
@media (max-width: 900px) {
    body.presenter {
        grid-template-columns: 1fr;
        grid-template-rows: auto 1fr;
    }
    .deck-sidebar {
        max-height: 40vh;
        border-right: none;
        border-bottom: 1px solid var(--slide-border);
        padding-top: 48px;
    }
    body.slide {
        padding: 40px 16px 24px;
    }
    .slide-header h1 {
        font-size: 22px;
    }
}