:root {
    --color-primary: #FF6B35;
    --color-primary-light: #FF8C5A;
    --color-primary-dark: #E55A2B;
    --color-secondary: #4ECDC4;
    --color-secondary-light: #7EDDD6;
    --color-secondary-dark: #3DBDB4;
    --color-accent: #FF6B9D;
    --color-accent-light: #FF8FB8;
    --color-accent-dark: #E55A8A;
    --color-success: #2ECC71;
    --color-warning: #F39C12;
    --color-text-primary: #2C3E50;
    --color-text-secondary: #7F8C8D;
    --color-bg-light: #F8F9FA;
    --color-bg-white: #FFFFFF;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.1);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.15);
    --radius-sm: 8px;
    --radius-md: 12px;
    --radius-lg: 16px;
    --radius-xl: 24px;
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    min-height: 100vh;
    overflow-x: hidden;
    position: relative;
}

.background-decorations {
    background: linear-gradient(135deg, #FFF5F0 0%, #FFF0F5 50%, #F0F8FF 100%);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    pointer-events: none;
    z-index: 0;
    overflow: hidden;
}

.letter {
    position: absolute;
    font-size: 120px;
    font-weight: bold;
    color: rgba(255, 107, 53, 0.06);
    font-family: "Comic Sans MS", "Chalkboard SE", sans-serif;
    user-select: none;
    animation: float 6s ease-in-out infinite;
}

.letter:nth-child(1) { top: 10%; left: 5%; animation-delay: 0s; }
.letter:nth-child(2) { top: 20%; right: 10%; animation-delay: 1s; }
.letter:nth-child(3) { top: 50%; left: 15%; animation-delay: 2s; }
.letter:nth-child(4) { top: 70%; right: 15%; animation-delay: 0.5s; }
.letter:nth-child(5) { top: 85%; left: 8%; animation-delay: 1.5s; }
.letter:nth-child(6) { top: 30%; right: 25%; animation-delay: 2.5s; }
.letter:nth-child(7) { top: 60%; left: 40%; animation-delay: 3s; }
.letter:nth-child(8) { top: 15%; left: 60%; animation-delay: 3.5s; }
.letter:nth-child(9) { top: 75%; left: 70%; animation-delay: 4s; }
.letter:nth-child(10) { top: 40%; left: 85%; animation-delay: 4.5s; }

.mouse-icon {
    position: absolute;
    font-size: 80px;
    opacity: 0.08;
    animation: float 8s ease-in-out infinite;
    user-select: none;
}

.mouse-icon:nth-child(11) { top: 5%; left: 25%; animation-delay: 1s; }
.mouse-icon:nth-child(12) { top: 35%; right: 5%; animation-delay: 2s; }
.mouse-icon:nth-child(13) { top: 65%; left: 55%; animation-delay: 3s; }
.mouse-icon:nth-child(14) { top: 90%; left: 20%; animation-delay: 4s; }
.mouse-icon:nth-child(15) { top: 25%; left: 45%; animation-delay: 5s; }

@keyframes float {
    0%, 100% { transform: translateY(0) rotate(0deg); }
    50% { transform: translateY(-20px) rotate(5deg); }
}

.container {
    position: relative;
    z-index: 1;
    max-width: 1600px;
    margin: 0 auto;
    padding: 100px 40px;
}

.page-header {
    text-align: center;
    margin-bottom: 60px;
}

.page-title {
    font-size: 48px;
    font-weight: 800;
    color: var(--color-primary);
    margin-bottom: 16px;
    text-shadow: 2px 2px 4px rgba(255, 107, 53, 0.2);
    letter-spacing: 2px;
}

.page-subtitle {
    font-size: 20px;
    color: var(--color-text-secondary);
    font-weight: 400;
}

.course-grid {
    display: grid;
    grid-template-columns: repeat(6, 1fr);
    gap: 28px;
    padding: 20px 0;
}

.course-card {
    background: var(--color-bg-white);
    border-radius: var(--radius-lg);
    padding: 32px 24px;
    text-align: center;
    cursor: pointer;
    transition: all 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    box-shadow: var(--shadow-md);
    position: relative;
    overflow: hidden;
    border: 3px solid transparent;
}

.course-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: linear-gradient(90deg, var(--color-primary), var(--color-secondary), var(--color-accent));
    opacity: 0;
    transition: opacity 0.3s ease;
}

.course-card:hover {
    transform: scale(1.08) translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--color-primary-light);
}

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

.card-icon {
    width: 90px;
    height: 90px;
    margin: 0 auto 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    transition: transform 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
    position: relative;
}

.course-card:hover .card-icon {
    transform: scale(1.15) rotate(5deg);
}

.card-icon svg {
    width: 64px;
    height: 64px;
}

.card-age {
    display: inline-block;
    padding: 6px 16px;
    background: linear-gradient(135deg, var(--color-primary), var(--color-accent));
    color: white;
    border-radius: 20px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 16px;
    box-shadow: 0 2px 8px rgba(255, 107, 53, 0.3);
}

.card-title {
    font-size: 20px;
    font-weight: 700;
    color: var(--color-text-primary);
    margin-bottom: 12px;
    line-height: 1.4;
}

.card-description {
    font-size: 15px;
    color: var(--color-text-secondary);
    line-height: 1.7;
    margin-top: 12px;
}

@media (max-width: 1400px) {
    .course-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 24px;
    }
    .page-title {
        font-size: 40px;
    }
    .container {
        padding: 40px 30px;
    }
}

@media (max-width: 1024px) {
    .course-grid {
        grid-template-columns: repeat(3, 1fr);
        gap: 20px;
    }
    .course-card {
        padding: 28px 20px;
    }
    .card-icon {
        width: 80px;
        height: 80px;
    }
    .card-icon svg {
        width: 56px;
        height: 56px;
    }
}

@media (max-width: 768px) {
    .course-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 16px;
    }
    .page-title {
        font-size: 32px;
    }
    .page-subtitle {
        font-size: 16px;
    }
    .container {
        padding: 30px 20px;
    }
    .course-card {
        padding: 24px 16px;
    }
    .card-title {
        font-size: 18px;
    }
    .card-description {
        font-size: 14px;
    }
    .letter {
        font-size: 80px;
    }
    .mouse-icon {
        font-size: 50px;
    }
}

@media (max-width: 480px) {
    .course-grid {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    .container {
        padding: 24px 16px;
    }
    .page-header {
        margin-bottom: 40px;
    }
    .course-card {
        padding: 28px 20px;
    }
    .card-icon {
        width: 75px;
        height: 75px;
    }
    .card-icon svg {
        width: 52px;
        height: 52px;
    }
    .letter {
        font-size: 60px;
    }
    .mouse-icon {
        font-size: 40px;
    }
}

.footer {
    text-align: center;
    margin-top: 80px;
    padding: 40px 20px;
    color: var(--color-text-secondary);
    font-size: 14px;
}

.footer-brand {
    font-size: 18px;
    font-weight: 600;
    color: var(--color-primary);
    margin-bottom: 8px;
}