@import url('https://fonts.googleapis.com/css2?family=Plus+Jakarta+Sans:wght@400;500;600;700&family=Source+Serif+4:wght@600&display=swap');

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

:root {
    --background: #f7f7f5;
    --surface: #ffffff;
    --surface-muted: #f0f0ed;
    --border: #dcdcd4;
    --text-primary: #1a1a1a;
    --text-secondary: #5a5a58;
    --text-faint: #9c9c99;
    --accent: #0f4c81;
    --accent-soft: rgba(15, 76, 129, 0.08);
    --success: #31775f;
    --error: #c24545;
    --warning: #c2812b;
    --shadow-soft: 0 18px 40px rgba(18, 24, 32, 0.08);
    --radius: 12px;
    --transition: all 0.22s ease;
}

body {
    font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--background);
    color: var(--text-primary);
    line-height: 1.65;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

#app {
    min-height: 100vh;
}

.container {
    max-width: 1100px;
    margin: 0 auto;
    padding: clamp(18px, 3vw, 44px) clamp(20px, 4.5vw, 60px);
    display: flex;
    flex-direction: column;
    gap: clamp(18px, 3.5vw, 32px);
}

.screen {
    display: none;
}

.screen.active {
    display: block;
}

header {
    display: grid;
    gap: 12px;
    padding-bottom: clamp(16px, 2.5vw, 26px);
    border-bottom: 1px solid var(--border);
}

h1 {
    font-family: 'Source Serif 4', 'Times New Roman', serif;
    font-size: clamp(2.3rem, 4.1vw, 3.4rem);
    font-weight: 600;
    letter-spacing: -0.02em;
    color: var(--text-primary);
}

.subtitle {
    font-size: clamp(1.05rem, 2.2vw, 1.3rem);
    color: var(--text-secondary);
    max-width: 42ch;
}

.stats-card {
    background: var(--surface);
    border: 1px solid var(--border);
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    padding: clamp(18px, 2.6vw, 24px);
}

.stat-label {
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.16em;
    color: var(--text-faint);
    margin-bottom: 8px;
}

.stat-value {
    font-family: 'Source Serif 4', 'Times New Roman', serif;
    font-size: clamp(1.9rem, 3vw, 2.4rem);
    color: var(--text-primary);
}

.mode-selection {
    display: grid;
    gap: clamp(14px, 3vw, 24px);
}

.mode-selection h2 {
    font-size: clamp(1.25rem, 2.1vw, 1.6rem);
    font-weight: 600;
}

.mode-buttons {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: clamp(14px, 2.8vw, 20px);
}

.mode-button {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: clamp(20px, 2.6vw, 28px);
    display: grid;
    gap: 10px;
    align-content: start;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
}

.mode-button:hover:not(:disabled) {
    border-color: var(--accent);
    box-shadow: var(--shadow-soft);
    transform: translateY(-4px);
}

.mode-button:disabled {
    color: var(--text-faint);
    cursor: not-allowed;
}

.mode-icon {
    font-size: 1.9rem;
    color: var(--accent);
}

.mode-title {
    font-size: 1rem;
    font-weight: 600;
}

.mode-description {
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.settings {
    border: 1px solid var(--border);
    background: var(--surface);
    padding: clamp(16px, 2.4vw, 22px);
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
}

.checkbox-label {
    display: inline-flex;
    gap: 10px;
    align-items: center;
    cursor: pointer;
    font-weight: 500;
    font-size: 0.95rem;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    border: 1px solid var(--border);
    background: var(--surface-muted);
    appearance: none;
    display: grid;
    place-items: center;
    transition: var(--transition);
}

.checkbox-label input[type="checkbox"]:checked {
    background: var(--accent);
    border-color: var(--accent);
}

.checkbox-label input[type="checkbox"]:checked::after {
    content: '';
    width: 8px;
    height: 8px;
    background: #fff;
}

.home-footer {
    display: grid;
    gap: 6px;
    font-size: 0.9rem;
    color: var(--text-secondary);
}

.home-footer .small {
    color: var(--text-faint);
    font-size: 0.8rem;
}

.home-footer a {
    color: var(--accent);
    text-decoration: none;
    border-bottom: 1px solid transparent;
    transition: var(--transition);
}

.home-footer a:hover {
    border-color: var(--accent);
}

.quiz-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    border-bottom: 1px solid var(--border);
    padding-bottom: 18px;
}

.back-button {
    border: 1px solid var(--border);
    background: transparent;
    padding: 10px 18px;
    font-size: 0.92rem;
    font-weight: 500;
    cursor: pointer;
    transition: var(--transition);
}

.back-button:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.quiz-header h2 {
    font-size: 1.25rem;
    font-weight: 600;
}

.progress-badge {
    font-size: 0.75rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.progress-bar {
    height: 6px;
    background: var(--surface-muted);
    margin-top: -6px;
    margin-bottom: clamp(20px, 3vw, 30px);
    position: relative;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: var(--accent);
    transition: width 0.3s ease;
    width: 0%;
}

.question-card {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: clamp(22px, 3vw, 32px);
    display: grid;
    gap: 14px;
}

.question-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.question-number {
    font-size: 0.78rem;
    text-transform: uppercase;
    letter-spacing: 0.18em;
    color: var(--text-faint);
}

.audio-button {
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-primary);
    padding: 8px 16px;
    font-size: 0.95rem;
    cursor: pointer;
    transition: var(--transition);
}

.audio-button:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.question-text {
    font-family: 'Source Serif 4', 'Times New Roman', serif;
    font-size: clamp(1.4rem, 2.6vw, 1.9rem);
    line-height: 1.45;
}

.input-section {
    background: var(--surface);
    border: 1px solid var(--border);
    padding: clamp(20px, 2.6vw, 28px);
    display: grid;
    gap: 16px;
}

.input-label {
    font-size: 0.75rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.input-row {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 14px;
    align-items: stretch;
}

#answer-input {
    width: 100%;
    min-height: 120px;
    padding: 16px;
    border: 1px solid var(--border);
    border-radius: 8px;
    background: var(--surface-muted);
    font-family: inherit;
    font-size: 1rem;
    resize: vertical;
    transition: var(--transition);
}

#answer-input:focus {
    outline: none;
    border-color: var(--accent);
    background: #fff;
    box-shadow: 0 0 0 3px var(--accent-soft);
}

.input-hint {
    font-size: 0.85rem;
    color: var(--text-secondary);
    margin-top: 10px;
}

.input-hint.listening {
    color: var(--accent);
}

.input-hint.error {
    color: var(--error);
}

.input-hint.success {
    color: var(--text-primary);
}

.voice-button {
    width: 54px;
    height: 54px;
    border-radius: 8px;
    border: 1px solid var(--border);
    background: var(--surface);
    color: var(--text-primary);
    font-size: 1.4rem;
    cursor: pointer;
    transition: var(--transition);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    align-self: start;
}

.voice-button:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.voice-button.recording {
    border-color: var(--error);
    color: var(--error);
    box-shadow: 0 0 0 6px rgba(194, 69, 69, 0.12);
}

.submit-button,
.next-button {
    border: 1px solid var(--accent);
    background: var(--accent);
    color: #fff;
    padding: 14px;
    font-size: 0.95rem;
    font-weight: 600;
    letter-spacing: 0.08em;
    text-transform: uppercase;
    cursor: pointer;
    transition: var(--transition);
}

.submit-button:hover:not(:disabled),
.next-button:hover {
    background: transparent;
    color: var(--accent);
}

.submit-button:disabled {
    background: var(--surface-muted);
    border-color: var(--border);
    color: var(--text-faint);
    cursor: not-allowed;
}

.modal {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(12, 16, 20, 0.5);
    z-index: 1000;
    padding: clamp(20px, 5vw, 40px);
    overflow-y: auto;
}

.modal.active {
    display: flex;
    align-items: center;
    justify-content: center;
}

.modal-content {
    background: var(--surface);
    border: 1px solid var(--border);
    max-width: 560px;
    width: 100%;
    max-height: 90vh;
    overflow-y: auto;
    padding: clamp(24px, 4vw, 36px);
    display: grid;
    gap: 18px;
}

.result-header {
    display: grid;
    gap: 12px;
    text-align: center;
}

.result-icon {
    font-size: 2.4rem;
}

.result-title {
    font-family: 'Source Serif 4', 'Times New Roman', serif;
    font-size: clamp(1.6rem, 2.8vw, 2rem);
}

.result-title.correct {
    color: var(--success);
}

.result-title.incorrect {
    color: var(--error);
}

.result-title.lookup {
    color: var(--warning);
}

.result-similarity {
    font-size: 0.95rem;
    color: var(--text-secondary);
}

.your-answer-section,
.accepted-answers-section,
.question-reference {
    display: grid;
    gap: 10px;
}

.your-answer-section h3,
.accepted-answers-section h3,
.question-reference h3 {
    font-size: 0.75rem;
    letter-spacing: 0.2em;
    text-transform: uppercase;
    color: var(--text-faint);
}

.answer-box {
    background: var(--surface-muted);
    border: 1px solid var(--border);
    padding: 16px;
    font-size: 0.98rem;
}

.accepted-answers-section .section-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    gap: 12px;
}

.audio-button-small {
    border: 1px solid var(--border);
    background: transparent;
    color: var(--text-primary);
    font-size: 0.85rem;
    padding: 6px 12px;
    display: inline-flex;
    align-items: center;
    gap: 6px;
    cursor: pointer;
    transition: var(--transition);
}

.audio-button-small:hover {
    border-color: var(--accent);
    color: var(--accent);
}

.accepted-answer-item {
    display: flex;
    gap: 10px;
    padding: 12px 14px;
    border: 1px solid var(--border);
    background: var(--surface);
}

.accepted-answer-item .icon {
    color: var(--success);
}

.reference-box {
    display: flex;
    gap: 12px;
    padding: 14px;
    border: 1px solid var(--border);
    background: var(--surface);
}

.complete-icon {
    font-size: 3rem;
}

.test-score {
    border: 1px solid var(--border);
    background: var(--surface-muted);
    padding: 22px;
    display: grid;
    gap: 10px;
}

.score-label {
    font-size: 0.75rem;
    letter-spacing: 0.18em;
    text-transform: uppercase;
    color: var(--text-faint);
    text-align: center;
}

.score-value {
    font-family: 'Source Serif 4', 'Times New Roman', serif;
    font-size: clamp(2.3rem, 4vw, 3rem);
    text-align: center;
}

.score-value.pass {
    color: var(--success);
}

.score-value.fail {
    color: var(--warning);
}

.score-result {
    font-size: 1.05rem;
    font-weight: 600;
    text-align: center;
}

.score-result.pass {
    color: var(--success);
}

.score-result.fail {
    color: var(--warning);
}

.score-info {
    font-size: 0.95rem;
    color: var(--text-secondary);
    text-align: center;
}

.complete-message {
    font-size: 1rem;
    color: var(--text-secondary);
    text-align: center;
}

@media (max-width: 820px) {
    .container {
        padding: clamp(28px, 6vw, 48px) clamp(18px, 6vw, 40px);
    }

    .quiz-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .mode-buttons {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 560px) {
    .settings {
        flex-direction: column;
        align-items: flex-start;
    }

    .input-row {
        grid-template-columns: 1fr;
    }

    .voice-button {
        width: 100%;
        height: 48px;
        align-self: stretch;
    }
}