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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #0f172a 0%, #1e293b 100%);
    color: #f8fafc;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    overflow-x: hidden;
    position: relative;
}

body::before {
    content: '';
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: radial-gradient(circle at 50% 50%, rgba(59, 130, 246, 0.1) 0%, transparent 70%),
                radial-gradient(circle at 80% 20%, rgba(139, 92, 246, 0.1) 0%, transparent 70%),
                radial-gradient(circle at 20% 80%, rgba(239, 68, 68, 0.1) 0%, transparent 70%);
    pointer-events: none;
    z-index: -1;
    animation: backgroundShift 20s ease-in-out infinite;
}

@keyframes backgroundShift {
    0%, 100% {
        transform: scale(1) rotate(0deg);
    }
    50% {
        transform: scale(1.1) rotate(1deg);
    }
}

.container {
    max-width: 1200px;
    width: 100%;
    text-align: center;
    animation: fadeIn 1s ease-in-out;
}

.header {
    margin-bottom: 40px;
}

.header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
    background: linear-gradient(45deg, #3b82f6, #8b5cf6);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    animation: glow 2s ease-in-out infinite alternate;
}

.subtitle {
    font-size: 1.2rem;
    color: #94a3b8;
}

.countdown {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 60px;
    flex-wrap: wrap;
}

.countdown-item {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-radius: 12px;
    padding: 20px;
    min-width: 120px;
    box-shadow: 0 8px 32px rgba(31, 38, 135, 0.37),
                0 0 20px rgba(59, 130, 246, 0.2) inset;
    position: relative;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

.countdown-item:hover {
    transform: translateY(-5px) scale(1.02);
    box-shadow: 0 12px 40px rgba(59, 130, 246, 0.4),
                0 0 30px rgba(59, 130, 246, 0.3) inset;
    border-color: rgba(59, 130, 246, 0.6);
}

.countdown-item::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, #3b82f6, #8b5cf6);
    animation: gradientFlow 3s ease-in-out infinite;
}

.countdown-item::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(59, 130, 246, 0.1), transparent);
    transition: left 0.6s ease;
}

.countdown-item:hover::after {
    left: 100%;
}

@keyframes gradientFlow {
    0%, 100% {
        background-position: 0% 50%;
    }
    50% {
        background-position: 100% 50%;
    }
}

.countdown-number {
    font-size: 2.5rem;
    font-weight: bold;
    color: #f8fafc;
    margin-bottom: 5px;
    font-family: 'Courier New', Courier, monospace;
}

.countdown-label {
    font-size: 0.9rem;
    color: #94a3b8;
    text-transform: uppercase;
    letter-spacing: 1px;
}

.subjects {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
    margin-bottom: 40px;
}

.subject-card {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-radius: 16px;
    padding: 30px;
    text-decoration: none;
    color: #f8fafc;
    transition: all 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    overflow: hidden;
    box-shadow: 0 8px 32px rgba(31, 38, 135, 0.37),
                0 0 20px rgba(59, 130, 246, 0.1) inset;
}

.subject-card:hover {
    transform: translateY(-15px) scale(1.03);
    box-shadow: 0 20px 48px rgba(59, 130, 246, 0.4),
                0 0 30px rgba(59, 130, 246, 0.2) inset;
    border-color: rgba(59, 130, 246, 0.6);
}

.subject-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(135deg, rgba(59, 130, 246, 0.1), rgba(139, 92, 246, 0.1));
    opacity: 0;
    transition: opacity 0.4s ease;
}

.subject-card:hover::before {
    opacity: 1;
}

.subject-card::after {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: linear-gradient(45deg, transparent, rgba(255, 255, 255, 0.1), transparent);
    transform: rotate(45deg);
    transition: left 0.7s ease;
}

.subject-card:hover::after {
    left: 150%;
}

#chinese {
    border-top: 3px solid #ef4444;
}

#chinese:hover {
    border-color: rgba(239, 68, 68, 0.8);
    box-shadow: 0 20px 48px rgba(239, 68, 68, 0.4),
                0 0 30px rgba(239, 68, 68, 0.2) inset;
}

#math {
    border-top: 3px solid #10b981;
}

#math:hover {
    border-color: rgba(16, 185, 129, 0.8);
    box-shadow: 0 20px 48px rgba(16, 185, 129, 0.4),
                0 0 30px rgba(16, 185, 129, 0.2) inset;
}

#english {
    border-top: 3px solid #f59e0b;
}

#english:hover {
    border-color: rgba(245, 158, 11, 0.8);
    box-shadow: 0 20px 48px rgba(245, 158, 11, 0.4),
                0 0 30px rgba(245, 158, 11, 0.2) inset;
}

.subject-icon {
    font-size: 3.5rem;
    margin-bottom: 20px;
    transition: transform 0.4s cubic-bezier(0.34, 1.56, 0.64, 1);
    position: relative;
    z-index: 1;
}

.subject-card:hover .subject-icon {
    transform: scale(1.2) rotate(10deg);
    filter: drop-shadow(0 0 15px rgba(255, 255, 255, 0.5));
}

.subject-card h2 {
    font-size: 1.6rem;
    margin-bottom: 15px;
    position: relative;
    z-index: 1;
    transition: color 0.3s ease;
}

#chinese:hover h2 {
    color: #ef4444;
}

#math:hover h2 {
    color: #10b981;
}

#english:hover h2 {
    color: #f59e0b;
}

.subject-card p {
    color: #94a3b8;
    font-size: 0.9rem;
    position: relative;
    z-index: 1;
    transition: color 0.3s ease;
}

.subject-card:hover p {
    color: #f8fafc;
}

.info {
    background: rgba(30, 41, 59, 0.8);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(59, 130, 246, 0.3);
    border-radius: 12px;
    padding: 25px;
    max-width: 800px;
    margin: 0 auto;
    box-shadow: 0 8px 32px rgba(31, 38, 135, 0.37),
                0 0 20px rgba(59, 130, 246, 0.1) inset;
    position: relative;
    overflow: hidden;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.info:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 40px rgba(59, 130, 246, 0.4),
                0 0 30px rgba(59, 130, 246, 0.2) inset;
}

.info::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: linear-gradient(90deg, #3b82f6, #8b5cf6);
}

.info h3 {
    font-size: 1.3rem;
    margin-bottom: 12px;
    color: #f8fafc;
    position: relative;
    z-index: 1;
    background: linear-gradient(45deg, #f8fafc, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.info p {
    color: #94a3b8;
    font-size: 0.9rem;
    line-height: 1.6;
    position: relative;
    z-index: 1;
    transition: color 0.3s ease;
}

.info:hover p {
    color: #cbd5e1;
}

@keyframes fadeIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes glow {
    from {
        text-shadow: 0 0 20px rgba(59, 130, 246, 0.5);
    }
    to {
        text-shadow: 0 0 30px rgba(139, 92, 246, 0.7);
    }
}

@media (max-width: 768px) {
    .header h1 {
        font-size: 2rem;
    }
    
    .countdown {
        gap: 15px;
    }
    
    .countdown-item {
        min-width: 100px;
        padding: 15px;
    }
    
    .countdown-number {
        font-size: 2rem;
    }
    
    .subjects {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .header h1 {
        font-size: 1.5rem;
    }
    
    .countdown-item {
        min-width: 80px;
        padding: 10px;
    }
    
    .countdown-number {
        font-size: 1.5rem;
    }
    
    .countdown-label {
        font-size: 0.8rem;
    }
}