:root {
    --bg-color: #0b0f19;
    --card-bg: #151b2b;
    --text-main: #f1f5f9;
    --text-muted: #94a3b8;
    --accent: #3b82f6;
    --correct: #10b981;
    --incorrect: #ef4444;
    --hover-bg: #1e293b;
    --border-color: #334155;
}

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

body {
    font-family: 'Outfit', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    line-height: 1.6;
    padding-bottom: 80px;
}

.hero {
    text-align: center;
    padding: 20px;
    background: linear-gradient(135deg, rgba(15,23,42,0.85) 0%, rgba(30,58,138,0.2) 100%);
    border-bottom: 1px solid var(--border-color);
    margin-bottom: 40px;
    position: sticky;
    top: 0;
    z-index: 100;
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
}

.hero h1 {
    font-size: 2.5rem;
    font-weight: 800;
    background: linear-gradient(to right, #60a5fa, #a78bfa);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 15px;
}

.hero p {
    color: var(--text-muted);
    font-size: 1.1rem;
    max-width: 600px;
    margin: 0 auto 20px auto;
}

.score-container {
    display: inline-block;
    background: rgba(255,255,255,0.05);
    padding: 10px 25px;
    border-radius: 30px;
    font-size: 1.2rem;
    font-weight: 600;
    border: 1px solid var(--border-color);
    box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

#score {
    color: #60a5fa;
    font-size: 1.8rem;
    padding-right: 5px;
}

.header-controls {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 15px;
}

.reset-btn {
    background-color: var(--incorrect);
    color: white;
    border: 1px solid rgba(255,255,255,0.1);
    padding: 10px 20px;
    border-radius: 30px;
    font-size: 1.05rem;
    font-weight: 600;
    cursor: pointer;
    font-family: inherit;
    transition: all 0.3s ease;
    box-shadow: 0 4px 15px rgba(239, 68, 68, 0.2);
}

.reset-btn:hover {
    background-color: #dc2626;
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(239, 68, 68, 0.4);
}

#quiz-container {
    max-width: 850px;
    margin: 0 auto;
    padding: 0 20px;
    display: flex;
    flex-direction: column;
    gap: 30px;
}

.question-card {
    background-color: var(--card-bg);
    border-radius: 20px;
    padding: 35px;
    box-shadow: 0 10px 25px rgba(0,0,0,0.3);
    border: 1px solid rgba(255,255,255,0.05);
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
    opacity: 0;
    transform: translateY(20px);
    animation: fadeInUp 0.6s forwards;
}

@keyframes fadeInUp {
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.question-card:hover {
    box-shadow: 0 15px 35px rgba(0,0,0,0.5);
    border-color: rgba(255,255,255,0.1);
}

.question-title {
    font-size: 1.35rem;
    font-weight: 600;
    margin-bottom: 25px;
    color: #e2e8f0;
    display: flex;
    gap: 18px;
    align-items: flex-start;
}

.question-number {
    background: var(--accent);
    color: white;
    width: 40px;
    height: 40px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    font-size: 1.1rem;
    flex-shrink: 0;
    box-shadow: 0 4px 10px rgba(59, 130, 246, 0.4);
}

.options-list {
    list-style: none;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.option {
    background-color: rgba(255,255,255,0.03);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    padding: 16px 20px;
    cursor: pointer;
    transition: all 0.2s ease;
    display: flex;
    align-items: center;
    gap: 18px;
    font-size: 1.05rem;
    position: relative;
    overflow: hidden;
}

.option:hover {
    background-color: var(--hover-bg);
    border-color: #475569;
    transform: translateX(5px);
}

.option-letter {
    font-weight: 800;
    background: rgba(255,255,255,0.1);
    width: 32px;
    height: 32px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 8px;
    color: #cbd5e1;
    transition: all 0.2s ease;
}

.option.correct {
    background-color: rgba(16, 185, 129, 0.1);
    border-color: var(--correct);
    color: #fff;
    pointer-events: none;
}

.option.correct .option-letter {
    background-color: var(--correct);
    color: white;
}

.option.incorrect {
    background-color: rgba(239, 68, 68, 0.1);
    border-color: var(--incorrect);
    color: #fff;
    pointer-events: none;
}

.option.incorrect .option-letter {
    background-color: var(--incorrect);
    color: white;
}

.option.disabled {
    pointer-events: none;
    opacity: 0.5;
}

.icon {
    margin-left: auto;
    font-size: 1.3rem;
    font-weight: bold;
    opacity: 0;
    transform: scale(0.5);
    transition: all 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

.option.correct .icon {
    opacity: 1;
    transform: scale(1);
    color: var(--correct);
}

.option.incorrect .icon {
    opacity: 1;
    transform: scale(1);
    color: var(--incorrect);
}

@media (max-width: 600px) {
    .hero {
        padding: 12px;
        margin-bottom: 25px;
    }
    .score-container {
        padding: 6px 16px;
        font-size: 1.05rem;
    }
    .reset-btn {
        padding: 6px 16px;
        font-size: 0.95rem;
    }
    #score {
        font-size: 1.4rem;
    }
    #quiz-container {
        padding: 0 10px;
        gap: 20px;
    }
    .question-card {
        padding: 20px 15px;
        border-radius: 15px;
    }
    .question-title {
        font-size: 1.15rem;
        gap: 12px;
        margin-bottom: 18px;
    }
    .question-number {
        width: 32px;
        height: 32px;
        font-size: 0.95rem;
    }
    .option {
        padding: 12px 14px;
        gap: 12px;
        font-size: 0.95rem;
        border-radius: 10px;
    }
    .option-letter {
        width: 28px;
        height: 28px;
        font-size: 0.9rem;
    }
    .icon {
        font-size: 1.1rem;
    }
}