/* 现代简约样式 - 内联CSS */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --primary-color: #f56a12;
    --primary-hover: #e05a08;
    --bg-gradient-start: #f8f9fa;
    --bg-gradient-end: #e9ecef;
    --text-primary: #333;
    --text-secondary: #666;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 16px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.15);
    --border-radius: 12px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "Helvetica Neue", Arial, "Noto Sans", sans-serif, "Apple Color Emoji", "Segoe UI Emoji", "Segoe UI Symbol";
    background: #EEEEEB;
    color: var(--text-primary);
    line-height: 1.6;
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* 导航栏 */
.navbar {
    background: #fff;
    padding: 0;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    box-shadow: var(--shadow-md);
}

.navbar .container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 10px 2em;
}

.navbar-header a {
    display: inline-block;
    transition: var(--transition);
}

.navbar-header a:hover {
    transform: scale(1.05);
}

.navbar-header img {
    width: 100%;
    height: 40px;
    display: block;
}

/* 主容器 */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 2rem;
    width: 100%;
}

.index-menu {
    margin-top: 100px;
    flex: 1;
    padding-bottom: 2rem;
}

.row {
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    gap: 1.5rem;
    margin: 0 -0.75rem;
}

/* 响应式列 */
[class*="col-"] {
    padding: 0 0.75rem;
}

.col-sm-5 {
    grid-column: span 5;
}

.col-sm-7 {
    grid-column: span 7;
}

.col-sm-4 {
    grid-column: span 4;
}

/* 语言选择卡片 */
.languang_t, .languang_c, .languang_e, .languang_j, .languang_k {
    text-decoration: none;
    display: block;
    height: 100%;
}

.box {
    background: #fff;
    border-radius: var(--border-radius);
    padding: 2.5rem;
    height: 100%;
    min-height: 180px;
    box-shadow: var(--shadow-sm);
    transition: var(--transition);
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.box::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: linear-gradient(90deg, var(--primary-color) 0%, var(--primary-hover) 100%);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

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

.box:hover::before {
    transform: scaleX(1);
}

.box h1 {
    font-size: 1.75rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text-primary);
    transition: var(--transition);
}

.box:hover h1 {
    color: var(--primary-color);
}

.box p {
    font-size: 0.95rem;
    line-height: 1.7;
    color: var(--text-secondary);
    margin: 0;
}

.mt-20 {
    margin-top: 0;
}

/* 不同语言卡片的特色配色（悬停时） */
.tw .box:hover { border-color: #dc3545; }
.tw .box:hover h1 { color: #dc3545; }
.tw .box::before { background: linear-gradient(90deg, #dc3545 0%, #c82333 100%); }

.cn .box:hover { border-color: #fd7e14; }
.cn .box:hover h1 { color: #fd7e14; }
.cn .box::before { background: linear-gradient(90deg, #fd7e14 0%, #e8590c 100%); }

.en .box:hover { border-color: #007bff; }
.en .box:hover h1 { color: #007bff; }
.en .box::before { background: linear-gradient(90deg, #007bff 0%, #0056b3 100%); }

.ja .box:hover { border-color: #28a745; }
.ja .box:hover h1 { color: #28a745; }
.ja .box::before { background: linear-gradient(90deg, #28a745 0%, #1e7e34 100%); }

.ko .box:hover { border-color: #6f42c1; }
.ko .box:hover h1 { color: #6f42c1; }
.ko .box::before { background: linear-gradient(90deg, #6f42c1 0%, #59339d 100%); }

/* 页脚 */
footer {
    background: #fff;
    margin-top: 20px;
    box-shadow: 0 -2px 8px rgba(0,0,0,0.05);
    padding: 2rem 2rem;
}

.index-footer {
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text-secondary);
    text-align: center;
    margin: 0;
}

.mtb-20 {
    margin: 0;
}

/* 响应式设计 */
@media (max-width: 991px) {
    .col-sm-5, .col-sm-7, .col-sm-4 {
        grid-column: span 12;
    }
    
    .navbar .container {
        padding: 10px 1em;
    }
    
    .container {
        padding: 0 1rem;
    }
    
    .index-menu {
        margin-top: 80px;
    }
    
    .box {
        padding: 2rem;
        min-height: 150px;
    }
    
    .box h1 {
        font-size: 1.5rem;
    }
    
    .box p {
        font-size: 0.9rem;
    }
}

@media (max-width: 576px) {
    .navbar-header img {
        height: 35px;
    }
    
    .box {
        padding: 1.5rem;
        min-height: 130px;
    }
    
    .box h1 {
        font-size: 1.3rem;
        margin-bottom: 0.75rem;
    }
    
    .box p {
        font-size: 0.85rem;
    }
    
    .index-footer {
        font-size: 0.8rem;
    }
}

/* 加载动画 */
@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

.box {
    animation: fadeInUp 0.6s ease-out;
}

.col-sm-5 .box { animation-delay: 0.1s; }
.col-sm-7 .box { animation-delay: 0.2s; }
.col-sm-4:nth-of-type(3) .box { animation-delay: 0.3s; }
.col-sm-4:nth-of-type(4) .box { animation-delay: 0.4s; }
.col-sm-4:nth-of-type(5) .box { animation-delay: 0.5s; }

/* 优化可访问性
a:focus, .box:focus-within {
    outline: 2px solid var(--primary-color);
    outline-offset: 4px;
} */

/* 打印样式 */
@media print {
    .navbar { display: none; }
    .box { box-shadow: none; border: 1px solid #ddd; }
}
.navbar-header{
    line-height: 1;
}