/* ========================================
   嘉思克建站 - 全局样式
   表盘壁纸风 | 纯白 + 浅灰 + 浅蓝
   玻璃拼接分层布局
======================================== */

:root {
    --primary-white: #ffffff;
    --light-gray: #f5f7fa;
    --medium-gray: #e8ecf1;
    --dark-gray: #333333;
    --text-gray: #666666;
    --light-blue: #e3f2fd;
    --accent-blue: #1976d2;
    --glass-bg: rgba(255, 255, 255, 0.85);
    --glass-border: rgba(255, 255, 255, 0.3);
    --shadow-soft: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);
    --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Hiragino Sans GB', 'Microsoft YaHei', sans-serif;
    background: linear-gradient(135deg, var(--light-gray) 0%, var(--primary-white) 50%, var(--light-blue) 100%);
    color: var(--dark-gray);
    line-height: 1.6;
    overflow-x: hidden;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: inherit;
    transition: var(--transition-smooth);
}

ul {
    list-style: none;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ========================================
   顶部导航栏 - 玻璃态固定定位
======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--glass-border);
    transition: var(--transition-smooth);
}

.header.scrolled {
    background: rgba(255, 255, 255, 0.95);
    box-shadow: var(--shadow-soft);
}

.nav-container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 20px;
    max-width: 1400px;
    margin: 0 auto;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
    font-size: 24px;
    font-weight: 700;
    color: var(--accent-blue);
}

.logo img {
    width: 45px;
    height: 45px;
    object-fit: contain;
}

.nav-menu {
    display: flex;
    gap: 8px;
}

.nav-item {
    position: relative;
}

.nav-link {
    display: block;
    padding: 12px 24px;
    font-size: 15px;
    font-weight: 500;
    color: var(--text-gray);
    border-radius: 8px;
    transition: var(--transition-smooth);
    position: relative;
    overflow: hidden;
}

.nav-link::before {
    content: '';
    position: absolute;
    bottom: 0;
    left: 50%;
    transform: translateX(-50%);
    width: 0;
    height: 3px;
    background: var(--accent-blue);
    transition: var(--transition-smooth);
    border-radius: 2px;
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-blue);
    background: var(--light-blue);
}

.nav-link:hover::before,
.nav-link.active::before {
    width: 80%;
}

.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    cursor: pointer;
    padding: 10px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--dark-gray);
    border-radius: 2px;
    transition: var(--transition-smooth);
}

.hamburger.active span:nth-child(1) {
    transform: rotate(45deg) translate(5px, 5px);
}

.hamburger.active span:nth-child(2) {
    opacity: 0;
}

.hamburger.active span:nth-child(3) {
    transform: rotate(-45deg) translate(7px, -6px);
}

/* ========================================
   页脚 - 玻璃态分层设计
======================================== */
.footer {
    background: var(--glass-bg);
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-top: 1px solid var(--glass-border);
    padding: 60px 0 30px;
    margin-top: 80px;
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 40px;
    margin-bottom: 40px;
}

.footer-section h3 {
    font-size: 18px;
    color: var(--accent-blue);
    margin-bottom: 20px;
    position: relative;
    padding-bottom: 10px;
}

.footer-section h3::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 40px;
    height: 2px;
    background: var(--accent-blue);
}

.footer-section p,
.footer-section a {
    color: var(--text-gray);
    font-size: 14px;
    line-height: 2;
}

.footer-section a:hover {
    color: var(--accent-blue);
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.footer-bottom {
    text-align: center;
    padding-top: 30px;
    border-top: 1px solid var(--medium-gray);
    color: var(--text-gray);
    font-size: 14px;
}

/* ========================================
   通用组件样式
======================================== */
.section {
    padding: 80px 0;
}

.section-title {
    text-align: center;
    margin-bottom: 60px;
}

.section-title h2 {
    font-size: 36px;
    color: var(--dark-gray);
    margin-bottom: 15px;
    position: relative;
    display: inline-block;
}

.section-title h2::after {
    content: '';
    position: absolute;
    bottom: -10px;
    left: 50%;
    transform: translateX(-50%);
    width: 60px;
    height: 3px;
    background: var(--accent-blue);
}

.section-title p {
    color: var(--text-gray);
    font-size: 16px;
    max-width: 600px;
    margin: 0 auto;
}

.btn {
    display: inline-block;
    padding: 14px 35px;
    background: var(--accent-blue);
    color: var(--primary-white);
    border-radius: 8px;
    font-weight: 600;
    font-size: 15px;
    transition: var(--transition-smooth);
    border: none;
    cursor: pointer;
}

.btn:hover {
    background: #1565c0;
    transform: translateY(-2px);
    box-shadow: var(--shadow-hover);
}

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

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

/* 卡片样式 */
.card {
    background: var(--glass-bg);
    backdrop-filter: blur(10px);
    border-radius: 16px;
    padding: 30px;
    border: 1px solid var(--glass-border);
    box-shadow: var(--shadow-soft);
    transition: var(--transition-smooth);
}

.card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-hover);
}

/* 网格布局 */
.grid-2 {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 30px;
}

.grid-3 {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 30px;
}

.grid-4 {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
}

/* 动画效果 */
.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity 0.6s ease, transform 0.6s ease;
}

.fade-in.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========================================
   响应式设计
======================================== */
@media (max-width: 1024px) {
    .grid-4 {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .grid-3 {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .hamburger {
        display: flex;
    }
    
    .nav-menu {
        position: fixed;
        top: 70px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 70px);
        background: var(--primary-white);
        flex-direction: column;
        padding: 30px;
        gap: 15px;
        transition: var(--transition-smooth);
        overflow-y: auto;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .nav-link {
        padding: 15px 20px;
        font-size: 16px;
    }
    
    .grid-2,
    .grid-3,
    .grid-4 {
        grid-template-columns: 1fr;
    }
    
    .section-title h2 {
        font-size: 28px;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 0 15px;
    }
    
    .logo {
        font-size: 20px;
    }
    
    .logo img {
        width: 35px;
        height: 35px;
    }
}