:root {
    --quiz-primary: #1458d4;
    --quiz-primary-dark: #0f3f9e;
    --quiz-ink: #0f172a;
    --quiz-muted: #64748b;
    --quiz-bg: #f3f6fb;
    --quiz-card: #ffffff;
    --quiz-border: #d9e2ef;
    --quiz-soft: #eef5ff;
    --quiz-green: #0f766e;
    --quiz-red: #dc2626;
    --quiz-amber: #d97706;
    --quiz-violet: #6d28d9;
    --quiz-shadow: 0 12px 30px rgba(15, 23, 42, 0.08);
}

html,
body {
    max-width: 100%;
    overflow-x: hidden;
}

body {
    background: var(--quiz-bg);
}

.quiz-app,
.quiz-app * {
    box-sizing: border-box;
    min-width: 0;
    max-width: 100%;
}

.quiz-app {
    width: min(100%, 1180px);
    margin: 0 auto;
    padding: 0.85rem;
}

.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;
}

.quiz-app .hidden,
.quiz-modal.hidden {
    display: none !important;
}

.quiz-screen {
    display: grid;
    gap: 1rem;
}

.subject-grid,
.quiz-set-list,
.result-grid,
.review-filter-row,
.modal-actions {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.85rem;
}

.subject-card,
.quiz-set-card,
.question-card,
.result-panel,
.review-card,
.screen-topbar,
.modal-card,
.palette-panel {
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: var(--quiz-card);
    box-shadow: var(--quiz-shadow);
}

.subject-card {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 0.85rem;
    align-items: center;
    min-height: 132px;
    padding: 1rem;
    text-align: left;
}

.subject-icon {
    display: grid;
    place-items: center;
    width: 54px;
    height: 54px;
    border-radius: 8px;
    background: var(--quiz-soft);
    color: var(--quiz-primary);
    font-size: 1.35rem;
}

.subject-card h2,
.quiz-set-card h3,
.screen-topbar h2,
.question-title,
.result-panel h2,
.review-card h3,
.modal-card h2 {
    margin: 0;
    color: var(--quiz-ink);
    line-height: 1.2;
    overflow-wrap: anywhere;
}

.subject-card h2 {
    font-size: 1.12rem;
}

.subject-meta,
.quiz-meta,
.result-subtext,
.review-card p,
.modal-card p {
    margin: 0;
    color: var(--quiz-muted);
}

.subject-meta {
    display: block;
    margin-top: 0.2rem;
    font-size: 0.9rem;
    font-weight: 800;
}

.subject-card .btn {
    grid-column: 1 / -1;
    width: 100%;
}

.screen-topbar {
    display: grid;
    gap: 0.7rem;
    padding: 0.9rem;
}

.quiz-back-btn,
.palette-toggle,
.palette-close {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    min-height: 42px;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: #fff;
    color: var(--quiz-primary);
    cursor: pointer;
    font-weight: 800;
}

.quiz-back-btn {
    width: max-content;
    padding: 0.55rem 0.75rem;
}

.message-box {
    padding: 0.8rem;
    border: 1px solid #bfdbfe;
    border-radius: 8px;
    background: #eff6ff;
    color: #1e3a8a;
    font-weight: 800;
}

.message-box.error {
    border-color: #fecaca;
    background: #fef2f2;
    color: #991b1b;
}

.quiz-set-card {
    display: grid;
    gap: 0.85rem;
    padding: 1rem;
    overflow: hidden;
}

.quiz-set-card > div:last-child {
    display: grid;
    gap: 0.75rem;
}

.quiz-card-head {
    display: grid;
    gap: 0.25rem;
}

.quiz-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
}

.meta-pill,
.status-badge {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-height: 30px;
    padding: 0.28rem 0.55rem;
    border-radius: 999px;
    background: var(--quiz-soft);
    color: var(--quiz-primary);
    font-size: 0.78rem;
    font-weight: 900;
    white-space: normal;
    overflow-wrap: anywhere;
}

.quiz-performance {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.55rem;
}

.quiz-set-card .btn {
    width: 100%;
}

.perf-tile {
    display: grid;
    gap: 0.1rem;
    padding: 0.65rem;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: #f8fafc;
}

.perf-tile span {
    color: var(--quiz-muted);
    font-size: 0.72rem;
    font-weight: 900;
    text-transform: uppercase;
}

.perf-tile strong {
    color: var(--quiz-ink);
    overflow-wrap: anywhere;
}

.btn,
button {
    font: inherit;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.45rem;
    min-height: 44px;
    padding: 0.7rem 0.9rem;
    border: 1px solid transparent;
    border-radius: 8px;
    cursor: pointer;
    font-weight: 850;
    line-height: 1.2;
    text-align: center;
    text-decoration: none;
}

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

.btn-primary:hover {
    background: var(--quiz-primary-dark);
}

.btn-outline {
    border-color: var(--quiz-primary);
    background: #fff;
    color: var(--quiz-primary);
}

.btn-ghost {
    border-color: var(--quiz-border);
    background: #fff;
    color: var(--quiz-ink);
}

.btn-danger {
    background: var(--quiz-red);
    color: #fff;
}

.btn:disabled {
    border-color: #cbd5e1;
    background: #e5e7eb;
    color: #64748b;
    cursor: not-allowed;
}

.exam-shell {
    display: grid;
    gap: 1rem;
}

.exam-main {
    display: grid;
    gap: 0.8rem;
}

.exam-topbar {
    position: sticky;
    top: 68px;
    z-index: 40;
    display: grid;
    gap: 0.75rem;
    padding: 0.75rem;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--quiz-shadow);
}

.exam-title-block,
.exam-status-block {
    display: grid;
    gap: 0.35rem;
}

.exam-title-block span,
.exam-status-block span:first-child {
    color: var(--quiz-muted);
    font-size: 0.82rem;
    font-weight: 850;
    text-transform: uppercase;
}

.exam-title-block strong {
    color: var(--quiz-ink);
    font-size: 1rem;
    overflow-wrap: anywhere;
}

.exam-status-block {
    grid-template-columns: 1fr;
    align-items: center;
}

.timer-pill {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 0.4rem;
    width: 100%;
    min-height: 40px;
    padding: 0.45rem 0.65rem;
    border-radius: 999px;
    background: #e0f2fe;
    color: #075985;
    font-weight: 900;
}

.timer-pill.warning {
    background: #ffedd5;
    color: #9a3412;
}

.palette-toggle {
    grid-column: 1 / -1;
}

.progress-track {
    height: 10px;
    overflow: hidden;
    border-radius: 999px;
    background: #dbeafe;
}

.progress-track div {
    width: 0%;
    height: 100%;
    background: linear-gradient(90deg, var(--quiz-primary), var(--quiz-green));
    transition: width 0.2s ease;
}

.question-card {
    display: grid;
    gap: 1rem;
    padding: 1rem;
}

.question-meta {
    display: flex;
    flex-wrap: wrap;
    gap: 0.45rem;
}

.question-title {
    font-size: 1.16rem;
}

.option-list {
    display: grid;
    gap: 0.65rem;
}

.answer-option {
    display: grid;
    grid-template-columns: auto 1fr;
    gap: 0.75rem;
    align-items: center;
    width: 100%;
    min-height: 54px;
    padding: 0.8rem;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: #fff;
    color: var(--quiz-ink);
    cursor: pointer;
    text-align: left;
}

.answer-option.selected {
    border-color: var(--quiz-primary);
    background: var(--quiz-soft);
}

.option-key {
    display: grid;
    place-items: center;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: #e2e8f0;
    color: var(--quiz-ink);
    font-weight: 900;
}

.exam-actions {
    position: sticky;
    bottom: 0;
    z-index: 35;
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.55rem;
    padding: 0.6rem;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: rgba(255, 255, 255, 0.98);
    box-shadow: var(--quiz-shadow);
}

.exam-actions .btn-danger {
    grid-column: 1 / -1;
}

.exam-actions .btn {
    width: 100%;
    min-width: 0;
    white-space: normal;
    overflow-wrap: anywhere;
}

.palette-panel {
    position: fixed;
    inset: auto 0 0;
    z-index: 1200;
    display: grid;
    gap: 1rem;
    max-height: 82vh;
    padding: 1rem;
    border-radius: 14px 14px 0 0;
    transform: translateY(105%);
    transition: transform 0.22s ease;
    overflow-y: auto;
}

.palette-panel.open {
    transform: translateY(0);
}

.palette-head {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 1rem;
}

.palette-head h2 {
    margin: 0;
    font-size: 1.08rem;
}

.palette-close {
    width: 42px;
    padding: 0;
}

.palette-grid {
    display: grid;
    grid-template-columns: repeat(5, minmax(0, 1fr));
    gap: 0.45rem;
}

.palette-btn {
    min-height: 40px;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: #e2e8f0;
    color: var(--quiz-ink);
    cursor: pointer;
    font-weight: 900;
}

.palette-btn.current {
    outline: 3px solid rgba(20, 88, 212, 0.35);
}

.palette-btn.not-answered,
.status-dot.not-answered {
    background: #fee2e2;
}

.palette-btn.answered,
.status-dot.answered {
    background: #dcfce7;
}

.palette-btn.marked,
.status-dot.marked {
    background: #ede9fe;
}

.palette-btn.answered-marked,
.status-dot.answered-marked {
    background: #fef3c7;
}

.palette-legend {
    display: grid;
    gap: 0.45rem;
    color: var(--quiz-muted);
    font-size: 0.85rem;
    font-weight: 700;
}

.status-dot {
    display: inline-block;
    width: 12px;
    height: 12px;
    margin-right: 0.35rem;
    border-radius: 50%;
    background: #e2e8f0;
    vertical-align: -1px;
}

.result-panel {
    display: grid;
    gap: 0.85rem;
    padding: 1rem;
}

.score-panel {
    text-align: center;
}

.score-number {
    display: block;
    color: var(--quiz-primary);
    font-size: clamp(2.6rem, 14vw, 4.4rem);
    font-weight: 900;
    line-height: 1;
}

.result-grid {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.result-tile {
    display: grid;
    gap: 0.15rem;
    padding: 0.75rem;
    border: 1px solid var(--quiz-border);
    border-radius: 8px;
    background: #f8fafc;
}

.result-tile span {
    color: var(--quiz-muted);
    font-size: 0.76rem;
    font-weight: 900;
    text-transform: uppercase;
}

.result-tile strong {
    color: var(--quiz-ink);
    font-size: 1.08rem;
}

.result-actions,
.review-actions {
    display: grid;
    grid-template-columns: 1fr;
    gap: 0.65rem;
}

.review-filter-row {
    grid-template-columns: repeat(2, minmax(0, 1fr));
}

.review-card {
    display: grid;
    gap: 0.75rem;
    padding: 1rem;
}

.review-answer {
    padding: 0.65rem;
    border-radius: 8px;
    background: #f8fafc;
    color: var(--quiz-ink);
}

.review-answer.correct {
    background: #ecfdf5;
    color: #166534;
}

.review-answer.wrong {
    background: #fef2f2;
    color: #991b1b;
}

.quiz-modal {
    position: fixed;
    inset: 0;
    z-index: 2000;
    display: grid;
    place-items: center;
    padding: 1rem;
    background: rgba(15, 23, 42, 0.55);
}

.modal-card {
    display: grid;
    gap: 0.85rem;
    width: min(100%, 430px);
    padding: 1rem;
}

:where(button, .btn, a):focus-visible {
    outline: 3px solid rgba(245, 158, 11, 0.6);
    outline-offset: 3px;
}

@media (min-width: 520px) {
    .subject-grid {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .subject-card .btn {
        width: max-content;
    }

    .result-actions,
    .review-actions,
    .modal-actions {
        grid-template-columns: repeat(2, minmax(0, 1fr));
    }

    .quiz-performance {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .exam-actions {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }

    .exam-actions .btn-danger {
        grid-column: 1 / -1;
    }
}

@media (min-width: 768px) {
    .quiz-app {
        padding: 1.2rem;
    }

    .screen-topbar {
        grid-template-columns: auto 1fr;
        align-items: center;
    }

    .quiz-set-card {
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: center;
    }

    .exam-topbar {
        grid-template-columns: minmax(0, 1fr) auto;
        align-items: center;
    }

    .exam-status-block {
        grid-template-columns: auto auto;
    }

    .timer-pill {
        width: max-content;
    }

    .palette-toggle {
        grid-column: auto;
    }

    .exam-actions {
        position: static;
        grid-template-columns: repeat(5, auto);
        justify-content: start;
    }

    .exam-actions .btn-danger {
        grid-column: auto;
    }

    .result-grid {
        grid-template-columns: repeat(4, minmax(0, 1fr));
    }

    .review-filter-row {
        grid-template-columns: repeat(5, minmax(0, auto));
        justify-content: start;
    }
}

@media (min-width: 900px) {
    .subject-grid {
        grid-template-columns: repeat(3, minmax(0, 1fr));
    }
}

@media (min-width: 1024px) {
    .exam-shell {
        grid-template-columns: minmax(0, 1fr) 310px;
        align-items: start;
    }

    .palette-toggle,
    .palette-close {
        display: none;
    }

    .palette-panel {
        position: sticky;
        top: 86px;
        max-height: calc(100vh - 100px);
        border-radius: 8px;
        transform: none;
    }

    .palette-grid {
        grid-template-columns: repeat(5, minmax(0, 1fr));
    }
}

@media (max-width: 425px) {
    .quiz-app {
        padding: 0.7rem;
    }

    .subject-card {
        min-height: 124px;
        padding: 0.9rem;
    }

    .subject-icon {
        width: 48px;
        height: 48px;
    }

}

@media (max-width: 320px) {
    .quiz-app {
        padding: 0.55rem;
    }

    .subject-card {
        grid-template-columns: 1fr;
    }

    .subject-icon {
        width: 44px;
        height: 44px;
    }

    .result-grid,
    .review-filter-row {
        grid-template-columns: 1fr;
    }
}