:root {
    --bg-primary: #0d1117;
    --bg-secondary: #161b22;
    --bg-tertiary: #21262d;
    --border: #30363d;
    --border-light: #3d444d;
    --text: #e6edf3;
    --text-secondary: #8b949e;
    --text-muted: #6e7681;
    --green: #238636;
    --green-bright: #3fb950;
    --green-bg: rgba(35, 134, 54, 0.15);
    --red: #f85149;
    --red-bg: rgba(248, 81, 73, 0.15);
    --blue: #2f81f7;
    --blue-bg: rgba(47, 129, 247, 0.15);
    --yellow: #d29922;
    --yellow-bg: rgba(210, 153, 34, 0.15);
    --gray: #484f58;
    --radius: 10px;
    --radius-sm: 6px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
    background: var(--bg-primary);
    color: var(--text);
    min-height: 100vh;
    line-height: 1.6;
}

.main-wrapper {
    min-height: 100vh;
    padding-bottom: 2rem;
}

.container {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1.5rem;
}

.centered {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 90vh;
}

/* ── Cards ─────────────────────────────────────────── */

.card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
}

.welcome-card {
    width: 100%;
    max-width: 480px;
    padding: 2.5rem;
}

.admin-login-card {
    width: 100%;
    max-width: 400px;
    padding: 2.5rem;
    text-align: center;
}
.admin-login-card h1 { margin-bottom: 1.5rem; font-size: 1.4rem; }

/* ── Logo / Welcome ────────────────────────────────── */

.logo-area { text-align: center; margin-bottom: 2rem; }
.logo-icon { color: var(--green-bright); margin-bottom: 0.75rem; }
.logo-area h1 { font-size: 1.5rem; font-weight: 700; margin-bottom: 0.25rem; }
.subtitle { color: var(--text-secondary); font-size: 0.9rem; }

/* ── Forms ─────────────────────────────────────────── */

.form-group { margin-bottom: 1.25rem; }
.form-group label {
    display: block;
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 0.4rem;
    color: var(--text-secondary);
}

input[type="text"],
input[type="password"],
input[type="number"],
input[type="email"],
select,
textarea {
    width: 100%;
    padding: 0.65rem 0.85rem;
    background: var(--bg-primary);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text);
    font-size: 0.95rem;
    transition: border-color 0.2s;
}
input:focus, select:focus, textarea:focus {
    outline: none;
    border-color: var(--blue);
    box-shadow: 0 0 0 3px var(--blue-bg);
}

.form-help { display: block; font-size: 0.78rem; color: var(--text-muted); margin-top: 0.3rem; }

.form-row { display: grid; grid-template-columns: 1fr 1fr; gap: 1rem; }
.form-row-3 { grid-template-columns: 1fr 1fr 1fr; }

.form-fieldset {
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 1rem;
    margin-bottom: 1.25rem;
}
.form-fieldset legend {
    font-size: 0.85rem;
    font-weight: 600;
    color: var(--text-secondary);
    padding: 0 0.5rem;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.95rem;
    padding: 0.5rem 0;
}
.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    accent-color: var(--green);
    cursor: pointer;
}

.form-actions {
    display: flex;
    justify-content: flex-end;
    gap: 0.75rem;
    margin-top: 1rem;
}

/* ── Topic buttons ─────────────────────────────────── */

.topic-buttons {
    display: flex;
    flex-wrap: wrap;
    gap: 0.6rem;
}

.topic-btn {
    padding: 0.6rem 1.2rem;
    background: var(--bg-primary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
    font-size: 0.95rem;
    font-weight: 600;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s, color 0.2s;
}
.topic-btn:hover {
    border-color: var(--border-light);
    color: var(--text);
}
.topic-btn.active {
    border-color: var(--blue);
    background: var(--blue-bg);
    color: var(--blue);
}

/* ── Radio cards ───────────────────────────────────── */

.radio-group { display: grid; grid-template-columns: 1fr 1fr; gap: 0.75rem; }
.radio-group-wrap { grid-template-columns: repeat(auto-fit, minmax(140px, 1fr)); }

.radio-card {
    display: block;
    cursor: pointer;
    background: var(--bg-primary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 0.75rem 1rem;
    transition: border-color 0.2s, background 0.2s;
}
.radio-card:hover { border-color: var(--border-light); }
.radio-card input { display: none; }
.radio-card input:checked + .radio-content { color: var(--blue); }
.radio-card:has(input:checked) {
    border-color: var(--blue);
    background: var(--blue-bg);
}
.topic-card:has(input:checked) {
    border-color: var(--green-bright);
    background: var(--green-bg);
}
.topic-card input:checked + .radio-content { color: var(--green-bright); }

.radio-content { display: flex; flex-direction: column; }
.radio-title { font-weight: 600; font-size: 0.95rem; }
.radio-desc { font-size: 0.8rem; color: var(--text-muted); }

/* ── Captcha ───────────────────────────────────────── */

.captcha-group {
    display: flex;
    justify-content: center;
    margin: 1rem 0;
}

/* ── Buttons ───────────────────────────────────────── */

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    padding: 0.6rem 1.25rem;
    border: 1px solid transparent;
    border-radius: var(--radius-sm);
    font-size: 0.9rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.15s;
    text-decoration: none;
    color: var(--text);
    background: transparent;
}

.btn-primary {
    background: var(--blue);
    color: #fff;
}
.btn-primary:hover { filter: brightness(1.15); }

.btn-success {
    background: var(--green);
    color: #fff;
}
.btn-success:hover { filter: brightness(1.15); }

.btn-danger {
    background: var(--red);
    color: #fff;
    font-size: 0.8rem;
    padding: 0.35rem 0.65rem;
}

.btn-ghost {
    border: 1px solid var(--border);
    color: var(--text-secondary);
}
.btn-ghost:hover { border-color: var(--text-secondary); color: var(--text); }

.btn-full { width: 100%; padding: 0.75rem; }

.btn-sm { font-size: 0.8rem; padding: 0.35rem 0.65rem; }

.btn:disabled { opacity: 0.4; cursor: not-allowed; }

/* ── Flash messages ────────────────────────────────── */

.flash-container {
    position: fixed;
    top: 1rem;
    right: 1rem;
    z-index: 9999;
    display: flex;
    flex-direction: column;
    gap: 0.5rem;
    max-width: 400px;
}
.flash {
    padding: 0.75rem 1rem;
    border-radius: var(--radius-sm);
    font-size: 0.88rem;
    animation: fadeIn 0.3s ease;
}
.flash-error { background: var(--red-bg); border: 1px solid var(--red); color: var(--red); }
.flash-success { background: var(--green-bg); border: 1px solid var(--green); color: var(--green-bright); }

@keyframes fadeIn { from { opacity: 0; transform: translateY(-0.5rem); } to { opacity: 1; transform: none; } }

/* ── Quiz page ─────────────────────────────────────── */

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 0.75rem;
}
.quiz-meta { display: flex; gap: 0.75rem; align-items: center; }
.quiz-topic { font-weight: 700; font-size: 1.05rem; }
.quiz-type-badge {
    font-size: 0.75rem;
    padding: 0.2rem 0.6rem;
    background: var(--blue-bg);
    color: var(--blue);
    border-radius: 999px;
    font-weight: 600;
}
.quiz-participant { color: var(--text-secondary); font-size: 0.9rem; }

.progress-bar-wrapper {
    background: var(--bg-tertiary);
    border-radius: 999px;
    height: 6px;
    margin-bottom: 2rem;
    overflow: hidden;
}
.progress-bar {
    height: 100%;
    background: var(--green);
    border-radius: 999px;
    width: 0%;
    transition: width 0.4s ease;
}

.quiz-body {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2rem;
}

.question-counter {
    text-align: center;
    color: var(--text-muted);
    font-size: 0.85rem;
    margin-bottom: 1rem;
}

.question-text {
    font-size: 1.15rem;
    font-weight: 500;
    line-height: 1.7;
    margin-bottom: 1.75rem;
}

.options-container { display: flex; flex-direction: column; gap: 0.75rem; margin-bottom: 2rem; }

.option-card {
    background: var(--bg-tertiary);
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 1rem 1.25rem;
    cursor: pointer;
    transition: border-color 0.2s, background 0.2s;
}
.option-card:hover:not(.disabled) { border-color: var(--border-light); background: #282e38; }

.option-card.selected { border-color: var(--blue); background: var(--blue-bg); }

.option-card.correct {
    border-color: var(--green-bright);
    background: var(--green-bg);
}

.option-card.wrong {
    border-color: var(--red);
    background: var(--red-bg);
}

.option-card.disabled { cursor: default; }
.option-card.disabled:hover { background: inherit; }
.option-card.correct:hover { background: var(--green-bg); }
.option-card.wrong:hover { background: var(--red-bg); }

.option-header {
    display: flex;
    gap: 0.6rem;
    align-items: flex-start;
}

.option-letter {
    font-weight: 700;
    min-width: 1.5rem;
    color: var(--text-secondary);
}

.option-text { font-weight: 500; }

.option-result {
    margin-top: 0.5rem;
    padding-top: 0.5rem;
    border-top: 1px solid var(--border);
    font-size: 0.85rem;
    color: var(--text-secondary);
}
.option-result .result-label {
    font-weight: 700;
    margin-right: 0.25rem;
}
.option-result .result-label.correct-label { color: var(--green-bright); }
.option-result .result-label.wrong-label { color: var(--red); }

.quiz-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
}
.nav-right { display: flex; gap: 0.75rem; }

/* ── Result page ───────────────────────────────────── */

.result-header { text-align: center; margin-bottom: 2rem; }
.result-title { font-size: 1.6rem; font-weight: 700; }
.result-title.success { color: var(--green-bright); }
.result-title.warning { color: var(--yellow); }

.result-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.5rem;
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 2rem;
    margin-bottom: 2rem;
    max-width: 700px;
    width: 100%;
}

.result-score-area {
    display: flex;
    align-items: center;
    gap: 2rem;
}

.circular-progress {
    position: relative;
    width: 140px;
    height: 140px;
    flex-shrink: 0;
}
.circular-progress svg { transform: rotate(-90deg); width: 100%; height: 100%; }
.circular-progress .bg {
    fill: none;
    stroke: var(--bg-tertiary);
    stroke-width: 8;
}
.circular-progress .fg {
    fill: none;
    stroke: var(--green-bright);
    stroke-width: 8;
    stroke-linecap: round;
    transition: stroke-dashoffset 1s ease;
}

.score-text {
    position: absolute;
    top: 50%; left: 50%;
    transform: translate(-50%, -50%);
    text-align: center;
}
.score-num { display: block; font-size: 1.5rem; font-weight: 700; }
.score-pct { display: block; font-size: 0.85rem; color: var(--text-secondary); }

.score-details { display: flex; flex-direction: column; gap: 0.75rem; }
.score-row {
    display: flex;
    justify-content: space-between;
    gap: 2rem;
    font-size: 1rem;
}
.score-row.correct strong { color: var(--green-bright); font-size: 1.3rem; }
.score-row.wrong strong { color: var(--red); font-size: 1.3rem; }

.result-info-area { padding: 0.5rem 0; }
.info-block h3 { font-size: 1rem; margin-bottom: 0.75rem; color: var(--text-secondary); }
.info-block ul { list-style: none; }
.info-block li { margin-bottom: 0.4rem; font-size: 0.9rem; }
.info-block li strong { color: var(--text-secondary); }

.result-actions { text-align: center; margin-top: 2rem; }

/* ── Review section ────────────────────────────────── */

.review-section h2 { margin-bottom: 1.5rem; }

.review-item {
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
}
.review-item:last-child { border-bottom: none; }

.review-q {
    display: flex;
    gap: 0.5rem;
    align-items: flex-start;
    margin-bottom: 0.75rem;
    flex-wrap: wrap;
}
.review-num { font-weight: 700; color: var(--text-muted); min-width: 2rem; }
.review-badge {
    font-size: 0.75rem;
    padding: 0.15rem 0.5rem;
    border-radius: 999px;
    font-weight: 700;
    margin-left: auto;
}
.bg-green { background: var(--green-bg); color: var(--green-bright); }
.bg-red { background: var(--red-bg); color: var(--red); }

.review-options { display: flex; flex-direction: column; gap: 0.3rem; padding-left: 2rem; }
.review-opt {
    font-size: 0.88rem;
    padding: 0.35rem 0.6rem;
    border-radius: var(--radius-sm);
    color: var(--text-secondary);
}
.review-opt .opt-letter { font-weight: 600; margin-right: 0.25rem; }
.review-opt.opt-correct { background: var(--green-bg); color: var(--green-bright); }
.review-opt.opt-wrong { background: var(--red-bg); color: var(--red); }
.opt-explain { display: block; font-size: 0.8rem; color: var(--text-muted); margin-top: 0.15rem; font-style: italic; }

/* ── Admin ─────────────────────────────────────────── */

.admin-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    flex-wrap: wrap;
    gap: 1rem;
}
.admin-header h1 { font-size: 1.4rem; }

.admin-nav { display: flex; gap: 0.25rem; }
.admin-nav a {
    padding: 0.45rem 0.9rem;
    border-radius: var(--radius-sm);
    text-decoration: none;
    color: var(--text-secondary);
    font-size: 0.88rem;
    font-weight: 500;
    transition: background 0.15s, color 0.15s;
}
.admin-nav a:hover { background: var(--bg-tertiary); color: var(--text); }
.admin-nav a.active { background: var(--blue-bg); color: var(--blue); }
.admin-nav .nav-logout { color: var(--red); }
.admin-nav .nav-logout:hover { background: var(--red-bg); }

.stats-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(160px, 1fr));
    gap: 1rem;
    margin-bottom: 2rem;
}
.stats-small { grid-template-columns: repeat(4, 1fr); }

.stat-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.25rem;
    text-align: center;
}
.stat-value { font-size: 2rem; font-weight: 700; }
.stat-label { font-size: 0.82rem; color: var(--text-secondary); margin-top: 0.15rem; }
.stat-sub { font-size: 0.78rem; color: var(--text-muted); }

.section-actions { margin-bottom: 1.5rem; }

.filter-bar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    gap: 1rem;
}
.filter-form select { width: auto; min-width: 200px; }

/* ── Tables ────────────────────────────────────────── */

.table-wrap { overflow-x: auto; }

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.88rem;
}
thead th {
    text-align: left;
    padding: 0.75rem;
    border-bottom: 2px solid var(--border);
    color: var(--text-secondary);
    font-size: 0.8rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.03em;
}
tbody td {
    padding: 0.75rem;
    border-bottom: 1px solid var(--border);
    vertical-align: middle;
}
tbody tr:hover { background: rgba(255,255,255,0.02); }

.actions-cell {
    display: flex;
    gap: 0.4rem;
    flex-wrap: wrap;
}

/* ── Badges ────────────────────────────────────────── */

.badge {
    display: inline-block;
    font-size: 0.75rem;
    font-weight: 600;
    padding: 0.2rem 0.55rem;
    border-radius: 999px;
}
.badge-green { background: var(--green-bg); color: var(--green-bright); }
.badge-blue { background: var(--blue-bg); color: var(--blue); }
.badge-red { background: var(--red-bg); color: var(--red); }
.badge-gray { background: rgba(110,118,129,0.15); color: var(--text-muted); }

/* ── Question preview (admin) ──────────────────────── */

.question-preview {
    border-bottom: 1px solid var(--border);
    padding: 1rem 0;
}
.question-preview:last-child { border-bottom: none; }
.qp-header { display: flex; align-items: center; gap: 0.75rem; margin-bottom: 0.5rem; }
.qp-num { font-weight: 700; color: var(--text-muted); }
.qp-text { font-weight: 500; margin-bottom: 0.5rem; }
.qp-options { padding-left: 1rem; }
.qp-opt { font-size: 0.88rem; color: var(--text-secondary); padding: 0.2rem 0; }
.qp-correct { color: var(--green-bright); font-weight: 600; }

/* ── Utilities ─────────────────────────────────────── */

.text-muted { color: var(--text-muted); }
.text-green { color: var(--green-bright); }
.text-red { color: var(--red); }
.text-sm { font-size: 0.8rem; }
.score-cell { font-weight: 600; }
.empty-state { text-align: center; padding: 2rem; }

code {
    background: var(--bg-tertiary);
    padding: 0.15rem 0.4rem;
    border-radius: 3px;
    font-size: 0.85em;
}

/* ── Responsive ────────────────────────────────────── */

@media (max-width: 768px) {
    .container { padding: 1rem; }
    .result-card { grid-template-columns: 1fr; padding: 1.5rem; }
    .result-score-area { justify-content: center; }
    .admin-header { flex-direction: column; align-items: flex-start; }
    .admin-nav { flex-wrap: wrap; }
    .stats-small { grid-template-columns: repeat(2, 1fr); }
    .form-row, .form-row-3 { grid-template-columns: 1fr; }
    .quiz-body { padding: 1.25rem; }
    .question-text { font-size: 1rem; }
    .filter-bar { flex-direction: column; align-items: stretch; }
    .actions-cell { flex-direction: column; }
}