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

body {
    font-family: system-ui, -apple-system, BlinkMacSystemFont, sans-serif;
    background-color: #0f0f0f;
    color: #e5e5e5;
    line-height: 1.6;
}

header {
    background-color: #151515;
    border-bottom: 1px solid #252525;
    padding: 1rem 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 10;
    flex-wrap: wrap;
    gap: 0.5rem;
}

header h1 {
    font-size: 1.4rem;
    font-weight: 600;
}

.subtitle {
    color: #9b9b9b;
    font-size: 0.85rem;
}

#quiz-info {
    display: flex;
    gap: 1rem;
    align-items: center;
    flex-wrap: wrap;
}

#score-count, #batch-info {
    background-color: #1a1a1a;
    padding: 0.5rem 0.9rem;
    border-radius: 8px;
    border: 1px solid #252525;
    font-size: 0.9rem;
}

main {
    max-width: 900px;
    margin: 0 auto;
    padding: 2rem 1rem;
}

.question-card {
    background-color: #151515;
    border: 1px solid #252525;
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.question-title {
    font-size: 1.05rem;
    margin-bottom: 1rem;
    color: #ffffff;
}

.options-grid {
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.option-btn {
    text-align: left;
    padding: 0.8rem 1rem;
    background-color: #1a1a1a;
    border: 1px solid #2a2a2a;
    color: #e5e5e5;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.95rem;
    transition: all 0.15s ease;
}

.option-btn:hover:not(:disabled) {
    background-color: #202020;
    border-color: #3a3a3a;
}

.option-btn:disabled {
    cursor: not-allowed;
}

.option-btn.correct {
    background-color: rgba(34, 197, 94, 0.16);
    border-color: #22c55e;
    color: #4ade80;
}

.option-btn.incorrect {
    background-color: rgba(239, 68, 68, 0.16);
    border-color: #ef4444;
    color: #f87171;
}

.controls {
    display: flex;
    justify-content: space-between;
    margin-top: 2rem;
    gap: 1rem;
}

.controls button {
    flex: 1;
    max-width: 160px;
    padding: 0.7rem 1.5rem;
    background-color: #1a1a1a;
    border: 1px solid #2a2a2a;
    color: #e5e5e5;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.95rem;
    transition: all 0.15s ease;
}

.controls button:hover:not(:disabled) {
    background-color: #202020;
    border-color: #3a3a3a;
}

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

.pager {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 0.4rem;
    margin-top: 1.25rem;
    padding-bottom: 2rem;
}

.page-btn {
    min-width: 40px;
    height: 40px;
    padding: 0 0.6rem;
    background-color: #151515;
    border: 1px solid #2a2a2a;
    color: #cfcfcf;
    border-radius: 8px;
    cursor: pointer;
    font-family: inherit;
    font-size: 0.9rem;
    transition: all 0.15s ease;
}

.page-btn:hover:not(:disabled):not(.active) {
    background-color: #202020;
    border-color: #3a3a3a;
    color: #ffffff;
}

.page-btn.active {
    background-color: #2563eb;
    border-color: #2563eb;
    color: #ffffff;
    font-weight: 600;
    cursor: default;
}

.page-btn.gap {
    border-color: transparent;
    background-color: transparent;
    cursor: default;
    color: #6b6b6b;
}

@media (max-width: 640px) {
    header {
        padding: 0.9rem 1rem;
    }
    main {
        padding: 1rem;
    }
    .question-card {
        padding: 1rem;
    }
}