/* === theme === */
:root {
    --bg: #fafafa;
    --bg-card: #fff;
    --bg-code: #1a1a2e;
    --text: #1a1a1a;
    --text-mid: #555;
    --text-muted: #888;
    --border: #e0e0e0;
    --border-light: #eee;
    --accent: #922B3E;
    --accent-hover: #6d222e;
    --green: #2d8a56;
    --amber: #b8860b;
    --red: #c0392b;
    --blue: #2563eb;
    --purple: #7c3aed;
    --orange: #d97706;

    --cat-sql: #2563eb;
    --cat-python: #d97706;
    --cat-stats: #2d8a56;
    --cat-ml: #c2410c;
    --cat-terminology: #7c3aed;
    --cat-behavioral: #be185d;
    --cat-product: #c2410c;
    --cat-review: #666;
    --cat-general: #666;
    --cat-mixed: #666;

    --mono: 'JetBrains Mono', 'SF Mono', Monaco, monospace;
    --sans: 'Inter', -apple-system, system-ui, sans-serif;
    --radius: 6px;
    --radius-lg: 10px;
}

[data-theme="dark"] {
    --bg: #111;
    --bg-card: #1a1a1a;
    --bg-code: #0d0d1a;
    --text: #e0e0e0;
    --text-mid: #aaa;
    --text-muted: #777;
    --border: #2a2a2a;
    --border-light: #222;
    --accent: #d4506a;
    --accent-hover: #e06880;
}

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

body {
    font-family: var(--sans);
    background: var(--bg);
    color: var(--text);
    font-size: 15px;
    line-height: 1.6;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* === layout === */
.container { max-width: 1100px; margin: 0 auto; padding: 1.5rem 1.25rem; }

.navbar {
    background: var(--bg-card);
    border-bottom: 1px solid var(--border);
    padding: 0 1.25rem;
    position: sticky;
    top: 0;
    z-index: 100;
}
.nav-content {
    max-width: 1100px;
    margin: 0 auto;
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 48px;
}
.nav-brand {
    font-family: var(--mono);
    font-weight: 600;
    font-size: 0.95rem;
    color: var(--accent);
    letter-spacing: -0.02em;
}
.nav-brand:hover { text-decoration: none; }
.nav-links { display: flex; align-items: center; gap: 1.25rem; }
.nav-links a {
    color: var(--text-muted);
    font-size: 0.82rem;
    font-weight: 500;
    letter-spacing: 0.01em;
}
.nav-links a:hover { color: var(--text); text-decoration: none; }
.theme-toggle {
    background: none; border: none; cursor: pointer;
    font-size: 1.1rem; padding: 2px; color: var(--text-muted);
}

.site-footer {
    text-align: center;
    padding: 3rem 1rem 2rem;
    font-size: 0.8rem;
}
.site-footer a { color: var(--text-muted); }
.site-footer a:hover { color: var(--accent); }

.breadcrumb {
    font-size: 0.8rem;
    color: var(--text-muted);
    margin-bottom: 1.25rem;
    font-family: var(--mono);
}
.breadcrumb a { color: var(--text-muted); }

/* === dashboard === */
.dashboard-header { margin-bottom: 1.75rem; }
.dashboard-header h1 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 1rem;
    letter-spacing: -0.02em;
}

.stats-row { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.stat-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.6rem 1rem;
    display: flex;
    flex-direction: column;
    align-items: center;
    min-width: 100px;
}
.stat-card.stat-due {
    border-color: var(--amber);
    background: color-mix(in srgb, var(--amber) 6%, var(--bg-card));
}
.stat-value { font-size: 1.5rem; font-weight: 700; font-family: var(--mono); }
.stat-label { font-size: 0.7rem; color: var(--text-muted); text-transform: uppercase; letter-spacing: 0.04em; }

.module-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 1rem;
}

.module-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1rem 1.25rem;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    transition: border-color 0.15s;
}
.module-card:hover { border-color: var(--accent); }
.module-card-header { display: flex; align-items: baseline; gap: 0.5rem; }
.module-number {
    font-family: var(--mono);
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--text-muted);
    background: var(--bg);
    padding: 1px 6px;
    border-radius: 3px;
}
.module-title { font-size: 1rem; font-weight: 600; letter-spacing: -0.01em; }
.module-subtitle { font-size: 0.8rem; color: var(--text-muted); }
.module-categories { display: flex; gap: 0.35rem; flex-wrap: wrap; }

.category-tag {
    font-family: var(--mono);
    font-size: 0.65rem;
    font-weight: 500;
    padding: 1px 6px;
    border-radius: 3px;
    text-transform: lowercase;
    letter-spacing: 0.02em;
}
.cat-sql { background: color-mix(in srgb, var(--cat-sql) 12%, var(--bg-card)); color: var(--cat-sql); }
.cat-python { background: color-mix(in srgb, var(--cat-python) 12%, var(--bg-card)); color: var(--cat-python); }
.cat-stats { background: color-mix(in srgb, var(--cat-stats) 12%, var(--bg-card)); color: var(--cat-stats); }
.cat-ml { background: color-mix(in srgb, var(--cat-ml) 12%, var(--bg-card)); color: var(--cat-ml); }
.cat-terminology { background: color-mix(in srgb, var(--cat-terminology) 12%, var(--bg-card)); color: var(--cat-terminology); }
.cat-behavioral { background: color-mix(in srgb, var(--cat-behavioral) 12%, var(--bg-card)); color: var(--cat-behavioral); }
.cat-product { background: color-mix(in srgb, var(--cat-product) 12%, var(--bg-card)); color: var(--cat-product); }
.cat-review, .cat-general, .cat-mixed { background: color-mix(in srgb, var(--cat-review) 12%, var(--bg-card)); color: var(--cat-review); }

/* === progress bar === */
.progress-bar-container {
    background: var(--border-light);
    border-radius: 4px;
    height: 6px;
    position: relative;
    overflow: hidden;
}
.progress-bar-container.large { height: 10px; margin-bottom: 0.4rem; }
.progress-bar-container.small { height: 4px; flex: 1; }
.progress-bar {
    height: 100%;
    background: var(--accent);
    border-radius: 4px;
    transition: width 0.4s ease;
}
.progress-text { font-size: 0.72rem; color: var(--text-muted); font-family: var(--mono); }

.module-stats {
    display: flex;
    justify-content: space-between;
    font-size: 0.75rem;
    color: var(--text-muted);
    font-family: var(--mono);
}

.module-actions { display: flex; gap: 0.4rem; margin-top: auto; }
.reset-form { margin-top: 0.2rem; }

/* === buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 0.4rem 0.85rem;
    border-radius: var(--radius);
    font-size: 0.82rem;
    font-weight: 500;
    font-family: var(--sans);
    border: none;
    cursor: pointer;
    transition: all 0.15s;
    text-decoration: none;
    white-space: nowrap;
}
.btn:hover { text-decoration: none; }

.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: var(--accent-hover); }

.btn-secondary { background: var(--border); color: var(--text); }
.btn-secondary:hover { background: color-mix(in srgb, var(--border) 70%, var(--text)); }

.btn-ghost { background: transparent; color: var(--text-muted); }
.btn-ghost:hover { background: var(--border-light); color: var(--text); }

.btn-sm { padding: 0.25rem 0.5rem; font-size: 0.75rem; }
.btn-lg { padding: 0.6rem 1.25rem; font-size: 0.9rem; }

.btn-correct { background: var(--green); color: #fff; }
.btn-correct:hover { background: color-mix(in srgb, var(--green) 80%, black); }

.btn-partial { background: var(--amber); color: #fff; }
.btn-partial:hover { background: color-mix(in srgb, var(--amber) 80%, black); }

.btn-incorrect { background: var(--red); color: #fff; }
.btn-incorrect:hover { background: color-mix(in srgb, var(--red) 80%, black); }

/* === study view === */
.module-header { margin-bottom: 1.5rem; }
.module-header h1 { font-size: 1.3rem; margin-bottom: 0.4rem; letter-spacing: -0.02em; }
.module-header .subtitle { color: var(--text-muted); margin-bottom: 0.75rem; font-size: 0.85rem; }

.section-list { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: 1.5rem; }
.section-card {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.75rem 1rem;
    transition: border-color 0.15s;
    color: var(--text);
}
.section-card:hover { border-color: var(--accent); text-decoration: none; }
.section-card.viewed { border-left: 3px solid var(--green); }
.section-card-left { display: flex; align-items: center; gap: 0.75rem; }
.section-number {
    font-family: var(--mono);
    font-size: 0.72rem;
    font-weight: 600;
    color: var(--text-muted);
    width: 24px;
    text-align: center;
}
.section-card h3 { font-size: 0.9rem; margin-bottom: 0.15rem; }
.check-mark { color: var(--green); font-size: 1.1rem; font-weight: 700; }
.module-action-bar { display: flex; gap: 0.75rem; margin-top: 1.5rem; }

/* === section content === */
.study-content { max-width: 760px; }
.section-header { margin-bottom: 1.5rem; }
.section-header h1 { font-size: 1.25rem; margin-top: 0.4rem; letter-spacing: -0.02em; }

.content-blocks { margin-bottom: 1.5rem; }
.text-block { margin-bottom: 0.75rem; }
.text-block p { margin-bottom: 0.6rem; }
.text-block strong { font-weight: 600; }
.text-block table {
    width: 100%;
    border-collapse: collapse;
    margin: 0.75rem 0;
    font-size: 0.85rem;
}
.text-block th, .text-block td {
    padding: 0.4rem 0.6rem;
    border: 1px solid var(--border);
    text-align: left;
}
.text-block th { background: var(--bg); font-weight: 600; }
.text-block ul, .text-block ol { padding-left: 1.25rem; margin-bottom: 0.6rem; }
.text-block li { margin-bottom: 0.2rem; }

pre {
    background: var(--bg-code);
    color: #cdd6f4;
    padding: 0.85rem 1rem;
    border-radius: var(--radius);
    overflow-x: auto;
    margin: 0.75rem 0;
    font-size: 0.82rem;
    line-height: 1.55;
    border: 1px solid color-mix(in srgb, var(--bg-code) 80%, var(--border));
}
pre code {
    background: none !important;
    padding: 0 !important;
    font-family: var(--mono);
    font-size: inherit;
    border-radius: 0;
}
code {
    font-family: var(--mono);
    font-size: 0.85em;
    background: color-mix(in srgb, var(--border) 50%, var(--bg));
    padding: 1px 5px;
    border-radius: 3px;
}

/* question prompt rendered markdown */
.question-prompt p { margin-bottom: 0.5rem; }
.question-prompt code {
    font-family: var(--mono);
    font-size: 0.85em;
    background: color-mix(in srgb, var(--border) 50%, var(--bg));
    padding: 1px 5px;
    border-radius: 3px;
}
.model-answer-text p { margin-bottom: 0.4rem; }
.model-answer-text code, .quiz-answer code, .quiz-prompt code {
    font-family: var(--mono);
    font-size: 0.85em;
    background: color-mix(in srgb, var(--border) 50%, var(--bg));
    padding: 1px 5px;
    border-radius: 3px;
}

.inline-quiz-section {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    margin-top: 1.5rem;
}
.inline-quiz-section h3 { margin-bottom: 0.75rem; font-size: 1rem; }
.inline-quiz { padding: 0.75rem 0; border-bottom: 1px solid var(--border-light); }
.inline-quiz:last-child { border-bottom: none; }
.quiz-prompt { margin-bottom: 0.5rem; }
.quiz-answer {
    margin-top: 0.5rem;
    padding: 0.6rem;
    background: var(--bg);
    border-radius: var(--radius);
    font-size: 0.9rem;
}

.section-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 1.5rem;
    padding-top: 1.25rem;
    border-top: 1px solid var(--border-light);
}

/* === flashcards === */
.flashcard-container { max-width: 640px; margin: 0 auto; text-align: center; }
.flashcard-progress { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.5rem; }
#card-counter { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; font-family: var(--mono); }

.flashcard-deck { perspective: 1200px; margin-bottom: 1.25rem; }
.flashcard { width: 100%; min-height: 260px; cursor: pointer; position: relative; }
.flashcard-inner {
    width: 100%; min-height: 260px;
    transition: transform 0.45s ease;
    transform-style: preserve-3d;
    position: relative;
}
.flashcard-inner.flipped { transform: rotateY(180deg); }
.flashcard-front, .flashcard-back {
    position: absolute; width: 100%; min-height: 260px;
    backface-visibility: hidden;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.75rem;
    display: flex; flex-direction: column;
    align-items: center; justify-content: center;
}
.flashcard-back {
    transform: rotateY(180deg);
    border-color: var(--accent);
    border-width: 2px;
}
.flashcard-front p, .flashcard-back p { font-size: 1rem; line-height: 1.55; }
.flashcard-front code, .flashcard-back code {
    font-family: var(--mono);
    font-size: 0.85em;
    background: color-mix(in srgb, var(--border) 50%, var(--bg));
    padding: 1px 5px;
    border-radius: 3px;
}
.flashcard-controls { display: flex; justify-content: center; gap: 0.75rem; margin-bottom: 0.75rem; }
.flashcard-hint { font-size: 0.72rem; color: var(--text-muted); font-family: var(--mono); }

/* === quiz === */
.quiz-config { max-width: 560px; }
.quiz-config h1 { margin-bottom: 0.4rem; font-size: 1.2rem; }
.quiz-config p { color: var(--text-muted); margin-bottom: 1.25rem; font-size: 0.9rem; }
.quiz-container { max-width: 760px; margin: 0 auto; }
.quiz-progress-bar { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 1.25rem; }
#quiz-counter { font-size: 0.8rem; color: var(--text-muted); white-space: nowrap; font-family: var(--mono); }

.question-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 1.25rem;
    animation: fadeIn 0.25s ease;
}
@keyframes fadeIn {
    from { opacity: 0; transform: translateY(6px); }
    to { opacity: 1; transform: translateY(0); }
}

.question-header { display: flex; align-items: center; gap: 0.4rem; margin-bottom: 0.85rem; }
.question-type-tag {
    font-family: var(--mono);
    font-size: 0.65rem;
    padding: 1px 6px;
    border-radius: 3px;
    background: var(--border-light);
    color: var(--text-muted);
}
.question-counter { margin-left: auto; font-size: 0.8rem; color: var(--text-muted); font-family: var(--mono); }
.question-prompt { font-size: 0.95rem; margin-bottom: 1rem; line-height: 1.6; }

.code-editor-wrapper {
    margin-bottom: 0.85rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
}
.code-editor-header {
    background: var(--bg-code);
    color: #777;
    padding: 0.3rem 0.65rem;
    font-size: 0.7rem;
    font-family: var(--mono);
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.code-editor {
    width: 100%;
    background: #1a1a2e;
    color: #cdd6f4;
    border: none;
    padding: 0.85rem;
    font-family: var(--mono);
    font-size: 0.82rem;
    line-height: 1.55;
    resize: vertical;
    tab-size: 2;
}
.code-editor:focus { outline: none; box-shadow: inset 0 0 0 2px var(--accent); }

.answer-textarea {
    width: 100%;
    background: var(--bg);
    color: var(--text);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.65rem;
    font-size: 0.9rem;
    line-height: 1.55;
    resize: vertical;
    font-family: var(--sans);
    margin-bottom: 0.85rem;
}
.answer-textarea:focus { outline: none; border-color: var(--accent); }

/* fill in blank */
.blank-input-group { display: flex; align-items: center; gap: 0.4rem; margin-bottom: 0.6rem; }
.blank-input {
    padding: 0.4rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    font-size: 0.9rem;
    font-family: var(--mono);
    background: var(--bg);
    color: var(--text);
}
.blank-input.full-width { width: 100%; margin-bottom: 0.85rem; }
.blank-input:focus { outline: none; border-color: var(--accent); }

/* multiple choice */
.mc-options { display: flex; flex-direction: column; gap: 0.4rem; margin-bottom: 0.85rem; }
.mc-option {
    display: flex; align-items: center; gap: 0.6rem;
    padding: 0.6rem 0.85rem;
    border: 1px solid var(--border);
    border-radius: var(--radius);
    cursor: pointer;
    transition: border-color 0.15s;
}
.mc-option:hover { border-color: var(--accent); }
.mc-option input { display: none; }
.mc-option input:checked + .mc-key { background: var(--accent); color: #fff; }
.mc-option input:checked ~ .mc-text { font-weight: 600; }
.mc-key {
    width: 24px; height: 24px;
    display: flex; align-items: center; justify-content: center;
    border-radius: 50%;
    background: var(--border-light);
    font-family: var(--mono);
    font-size: 0.72rem;
    font-weight: 600;
    flex-shrink: 0;
}

/* star timer */
.star-timer-section { text-align: center; margin-bottom: 1.25rem; }
.star-instruction { color: var(--text-muted); font-size: 0.85rem; margin-top: 0.6rem; }
.timer-ring { width: 110px; height: 110px; margin: 0 auto 0.75rem; position: relative; }
.timer-ring svg { width: 100%; height: 100%; transform: rotate(-90deg); }
.timer-bg { fill: none; stroke: var(--border); stroke-width: 5; }
.timer-fill {
    fill: none; stroke: var(--accent); stroke-width: 5;
    stroke-dasharray: 283; stroke-dashoffset: 0;
    stroke-linecap: round; transition: stroke-dashoffset 1s linear;
}
.timer-text {
    position: absolute; top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    font-size: 1.2rem; font-weight: 700;
    font-family: var(--mono);
    font-variant-numeric: tabular-nums;
}

/* quiz result */
.result-card { animation: fadeIn 0.25s ease; }
.result-columns { display: grid; grid-template-columns: 1fr 1fr; gap: 0.85rem; margin-bottom: 1.25rem; }
@media (max-width: 600px) { .result-columns { grid-template-columns: 1fr; } }
.result-col h4 {
    font-size: 0.72rem; color: var(--text-muted); margin-bottom: 0.4rem;
    text-transform: uppercase; letter-spacing: 0.05em; font-family: var(--mono);
}
.user-answer-text, .model-answer-text {
    background: var(--bg);
    padding: 0.65rem;
    border-radius: var(--radius);
    font-size: 0.85rem;
    line-height: 1.55;
    white-space: pre-wrap;
}

.rubric-checklist {
    margin-bottom: 1.25rem;
    padding: 0.85rem;
    background: var(--bg);
    border-radius: var(--radius);
}
.rubric-checklist h4 { margin-bottom: 0.6rem; font-size: 0.85rem; }
.rubric-item { display: flex; align-items: center; gap: 0.4rem; padding: 0.2rem 0; cursor: pointer; }
.rubric-item input[type="checkbox"] { accent-color: var(--green); }

.grade-buttons { display: flex; align-items: center; gap: 0.6rem; padding-top: 0.85rem; border-top: 1px solid var(--border-light); }
.grade-label { font-size: 0.85rem; font-weight: 500; margin-right: auto; }

/* quiz complete */
.quiz-complete { text-align: center; padding: 2.5rem 1rem; animation: fadeIn 0.4s ease; }
.completion-icon {
    width: 72px; height: 72px; line-height: 72px;
    font-size: 2rem; border-radius: 50%;
    background: color-mix(in srgb, var(--green) 12%, var(--bg-card));
    color: var(--green);
    margin: 0 auto 1.25rem;
    animation: scaleIn 0.4s ease;
}
@keyframes scaleIn { from { transform: scale(0); } to { transform: scale(1); } }
.completion-stats { display: flex; justify-content: center; gap: 0.75rem; margin: 1.25rem 0; }
.completion-actions { display: flex; justify-content: center; gap: 0.75rem; margin-top: 1.25rem; }

/* === forms === */
.form-group { margin-bottom: 0.85rem; }
.form-group label { display: block; font-weight: 500; margin-bottom: 0.25rem; font-size: 0.82rem; }
.form-input, .form-select {
    width: 100%; padding: 0.4rem 0.65rem;
    border: 1px solid var(--border); border-radius: var(--radius);
    font-size: 0.85rem; background: var(--bg); color: var(--text);
    font-family: var(--sans);
}
.form-select { cursor: pointer; }
.form-textarea {
    width: 100%; padding: 0.65rem;
    border: 1px solid var(--border); border-radius: var(--radius);
    font-size: 0.85rem; font-family: var(--sans);
    line-height: 1.55; resize: vertical;
    background: var(--bg); color: var(--text);
}
.form-input:focus, .form-select:focus, .form-textarea:focus {
    outline: none; border-color: var(--accent);
}
.form-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(180px, 1fr)); gap: 0.75rem; }
.form-actions { display: flex; gap: 0.4rem; margin-top: 0.75rem; }
.checkbox-group { display: flex; flex-wrap: wrap; gap: 0.4rem; }
.checkbox-label { display: flex; align-items: center; gap: 0.25rem; cursor: pointer; font-size: 0.85rem; }
.checkbox-label input { accent-color: var(--accent); }
input[type="range"] { width: 100%; accent-color: var(--accent); }

/* === admin === */
.filter-bar { margin-bottom: 1.25rem; }
.filter-form { display: flex; gap: 0.4rem; flex-wrap: wrap; }
.filter-form .form-select { width: auto; min-width: 140px; }
.results-count { color: var(--text-muted); font-size: 0.8rem; margin-bottom: 0.75rem; font-family: var(--mono); }

.add-question-panel {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 0.85rem 1rem;
    margin-bottom: 1.25rem;
}
.add-question-panel summary { cursor: pointer; font-size: 0.85rem; }
.add-question-panel[open] summary { margin-bottom: 0.75rem; }

.question-list { display: flex; flex-direction: column; gap: 0.4rem; }
.question-list-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.75rem;
}
.question-list-header { display: flex; align-items: center; gap: 0.4rem; margin-bottom: 0.35rem; flex-wrap: wrap; }
.question-list-prompt { font-size: 0.88rem; }
.question-details { margin-top: 0.6rem; }
.question-details summary { color: var(--accent); cursor: pointer; font-size: 0.8rem; }
.answer-preview {
    background: var(--bg);
    padding: 0.6rem;
    border-radius: var(--radius);
    font-size: 0.82rem;
    margin: 0.6rem 0;
    white-space: pre-wrap;
    font-family: var(--mono);
}
.edit-form { margin-top: 0.6rem; }

.badge {
    font-family: var(--mono);
    font-size: 0.6rem;
    padding: 1px 5px;
    border-radius: 3px;
    font-weight: 500;
}
.badge-manual { background: color-mix(in srgb, var(--purple) 12%, var(--bg-card)); color: var(--purple); }

/* preview */
.preview-section { margin-top: 1.5rem; }
.preview-info { background: var(--bg); padding: 0.75rem; border-radius: var(--radius); margin-bottom: 0.75rem; }
.preview-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 0.6rem;
    margin-bottom: 0.4rem;
}

/* empty state */
.empty-state { text-align: center; padding: 3rem 1rem; }
.empty-state h2 { margin-bottom: 0.6rem; font-size: 1.2rem; }
.empty-state p { color: var(--text-muted); margin-bottom: 1.25rem; }
.empty-state .btn { margin: 0.2rem; }

/* flash messages */
.flash-messages { margin-bottom: 0.85rem; }
.flash {
    padding: 0.5rem 0.75rem;
    border-radius: var(--radius);
    margin-bottom: 0.4rem;
    font-size: 0.85rem;
    border: 1px solid;
}
.flash-success { background: color-mix(in srgb, var(--green) 8%, var(--bg-card)); color: var(--green); border-color: var(--green); }
.flash-error { background: color-mix(in srgb, var(--red) 8%, var(--bg-card)); color: var(--red); border-color: var(--red); }

/* utilities */
.hidden { display: none !important; }
.text-muted { color: var(--text-muted); font-size: 0.8rem; }

@media (max-width: 768px) {
    .module-grid { grid-template-columns: 1fr; }
    .stats-row { overflow-x: auto; }
    .nav-links { gap: 0.6rem; font-size: 0.75rem; }
    .grade-buttons { flex-wrap: wrap; }
}