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

:root {
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    --light-bg: #ecf0f1;
    --dark-text: #2c3e50;
    --light-text: #7f8c8d;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    line-height: 1.6;
    color: var(--dark-text);
    background-color: #fff;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* 导航栏样式 */
.navbar {
    background-color: var(--primary-color);
    color: white;
    position: fixed;
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 10px rgba(0,0,0,0.1);
}

.navbar .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
}

.logo {
    font-size: 1.5rem;
    font-weight: bold;
    color: white;
}

.nav-links {
    display: flex;
    list-style: none;
    gap: 30px;
}

.nav-links a {
    color: white;
    text-decoration: none;
    transition: color 0.3s ease;
}

.nav-links a:hover {
    color: var(--secondary-color);
}

/* Hero区域样式 */
.hero {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 150px 0 100px;
    text-align: center;
}

.hero h1 {
    font-size: 3rem;
    margin-bottom: 20px;
    animation: fadeInDown 0.8s ease;
}

.hero p {
    font-size: 1.2rem;
    margin-bottom: 30px;
    opacity: 0.9;
    animation: fadeInUp 0.8s ease;
}

@keyframes fadeInDown {
    from {
        opacity: 0;
        transform: translateY(-30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

@keyframes fadeInUp {
    from {
        opacity: 0;
        transform: translateY(30px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* 按钮样式 */
.btn {
    display: inline-block;
    padding: 12px 30px;
    border-radius: 5px;
    text-decoration: none;
    font-weight: bold;
    transition: all 0.3s ease;
    cursor: pointer;
    border: none;
}

.btn-primary {
    background-color: var(--accent-color);
    color: white;
}

.btn-primary:hover {
    background-color: #c0392b;
    transform: translateY(-2px);
}

.btn-secondary {
    background-color: var(--secondary-color);
    color: white;
}

.btn-secondary:hover {
    background-color: #2980b9;
    transform: translateY(-2px);
}

.btn-outline {
    border: 2px solid var(--secondary-color);
    color: var(--secondary-color);
    background: transparent;
}

.btn-outline:hover {
    background-color: var(--secondary-color);
    color: white;
}

/* 算法分类区域 */
.algorithms-section,
.practice-section,
.resources-section {
    padding: 80px 0;
}

.algorithms-section {
    background-color: var(--light-bg);
}

.algorithms-section h2,
.practice-section h2,
.resources-section h2 {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 50px;
    color: var(--primary-color);
}

.algorithm-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.algorithm-card {
    background: white;
    padding: 30px;
    border-radius: 10px;
    box-shadow: 0 5px 20px rgba(0,0,0,0.1);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.algorithm-card:hover {
    transform: translateY(-10px);
    box-shadow: 0 10px 30px rgba(0,0,0,0.15);
}

.algorithm-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
    font-size: 1.5rem;
}

.algorithm-card p {
    color: var(--light-text);
    margin-bottom: 20px;
}

/* 练习平台区域 */
.practice-platforms {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 30px;
}

.platform-card {
    text-align: center;
    padding: 40px 30px;
    border: 2px solid #eee;
    border-radius: 10px;
    transition: border-color 0.3s ease;
}

.platform-card:hover {
    border-color: var(--secondary-color);
}

.platform-card h3 {
    color: var(--primary-color);
    margin-bottom: 15px;
}

.platform-card p {
    color: var(--light-text);
    margin-bottom: 20px;
}

/* 资源区域 */
.resources-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.resource-item {
    background: var(--light-bg);
    padding: 30px;
    border-radius: 10px;
}

.resource-item h3 {
    color: var(--primary-color);
    margin-bottom: 20px;
}

.resource-item ul {
    list-style: none;
}

.resource-item li {
    padding: 10px 0;
    border-bottom: 1px solid #ddd;
    color: var(--dark-text);
}

.resource-item li:last-child {
    border-bottom: none;
}

/* 页脚 */
.footer {
    background-color: var(--primary-color);
    color: white;
    text-align: center;
    padding: 30px 0;
}

/* 响应式设计 */
@media (max-width: 768px) {
    .navbar .container {
        flex-direction: column;
        gap: 15px;
    }

    .nav-links {
        gap: 15px;
    }

    .hero h1 {
        font-size: 2rem;
    }

    .algorithm-grid,
    .practice-platforms,
    .resources-grid {
        grid-template-columns: 1fr;
    }
}

/* 算法详情页样式 */
.algorithm-detail {
    padding: 100px 0 50px;
}

.algorithm-detail h2 {
    color: var(--primary-color);
    margin-bottom: 30px;
}

.algorithm-detail h3 {
    color: var(--secondary-color);
    margin: 30px 0 15px;
}

.algorithm-content {
    background: var(--light-bg);
    padding: 30px;
    border-radius: 10px;
    margin: 20px 0;
}

.code-block {
    background: #282c34;
    color: #abb2bf;
    padding: 20px;
    border-radius: 5px;
    overflow-x: auto;
    font-family: 'Consolas', 'Monaco', monospace;
    margin: 15px 0;
}

.code-block pre {
    margin: 0;
}

/* 多语言代码标签页样式 */
.code-tabs {
    margin: 20px 0;
}

.code-tab-header {
    display: flex;
    gap: 5px;
    margin-bottom: 0;
    border-bottom: none;
}

.code-tab-btn {
    padding: 10px 20px;
    border: none;
    background: #e0e0e0;
    color: #666;
    cursor: pointer;
    border-radius: 5px 5px 0 0;
    font-size: 14px;
    font-weight: 500;
    transition: all 0.3s ease;
}

.code-tab-btn:hover {
    background: #d0d0d0;
}

.code-tab-btn.active {
    background: #282c34;
    color: #fff;
}

.code-tab-content {
    display: none;
    background: #282c34;
    border-radius: 0 5px 5px 5px;
    padding: 20px;
}

.code-tab-content.active {
    display: block;
}

.code-tab-content .code-block {
    margin: 0;
    background: transparent;
    border-radius: 0;
    padding: 0;
}

.complexity {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 20px;
    margin: 20px 0;
}

.complexity-item {
    background: white;
    padding: 20px;
    border-radius: 5px;
    text-align: center;
}

.complexity-item h4 {
    color: var(--primary-color);
    margin-bottom: 10px;
}

.back-link {
    display: inline-block;
    margin-bottom: 30px;
    color: var(--secondary-color);
    text-decoration: none;
}

.back-link:hover {
    text-decoration: underline;
}