/* ========================================
   搜优学建站 - 全局样式表
   风格：滑雪装备风（冰雪白 + 深海蓝 + 炽热红）
   布局：对角斜线分割非对称布局
   ======================================== */

:root {
    --ice-white: #f8f9fa;
    --snow-white: #ffffff;
    --deep-sea-blue: #0a2342;
    --ocean-blue: #1e3d59;
    --bright-red: #e63946;
    --fire-red: #d62828;
    --gray-light: #e9ecef;
    --gray-medium: #adb5bd;
    --text-dark: #212529;
    --text-light: #6c757d;
}

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

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Helvetica Neue', Arial, 'Microsoft YaHei', sans-serif;
    line-height: 1.6;
    color: var(--text-dark);
    background-color: var(--ice-white);
    overflow-x: hidden;
}

a {
    text-decoration: none;
    color: inherit;
    transition: all 0.3s ease;
}

ul, ol {
    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
   ======================================== */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    background: transparent;
    transition: all 0.4s ease;
    padding: 20px 0;
}

.header.scrolled {
    background: rgba(10, 35, 66, 0.95);
    backdrop-filter: blur(10px);
    padding: 15px 0;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
}

.header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo img {
    height: 50px;
    width: auto;
}

.logo-text {
    font-size: 24px;
    font-weight: 700;
    color: var(--snow-white);
    letter-spacing: 1px;
}

.nav-menu {
    display: flex;
    gap: 35px;
}

.nav-link {
    color: var(--snow-white);
    font-size: 16px;
    font-weight: 500;
    position: relative;
    padding: 8px 0;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--bright-red);
    transition: width 0.3s ease;
}

.nav-link:hover::after,
.nav-link.active::after {
    width: 100%;
}

.nav-link:hover {
    color: var(--bright-red);
}

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

.hamburger span {
    width: 30px;
    height: 3px;
    background: var(--snow-white);
    transition: all 0.3s ease;
}

.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);
}

/* ========================================
   对角斜线布局系统
   ======================================== */
.diagonal-section {
    position: relative;
    padding: 100px 0;
    overflow: hidden;
}

.diagonal-section::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: linear-gradient(135deg, var(--deep-sea-blue) 0%, var(--ocean-blue) 100%);
    clip-path: polygon(0 0, 100% 0, 100% 85%, 0 100%);
    z-index: -1;
}

.diagonal-section.reverse::before {
    background: linear-gradient(135deg, var(--ice-white) 0%, var(--gray-light) 100%);
    clip-path: polygon(0 15%, 100% 0, 100% 100%, 0 100%);
}

.diagonal-section.accent::before {
    background: linear-gradient(135deg, var(--bright-red) 0%, var(--fire-red) 100%);
    clip-path: polygon(0 0, 100% 0, 100% 75%, 0 90%);
}

.section-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 60px;
    align-items: center;
}

.section-image {
    position: relative;
    overflow: hidden;
    border-radius: 20px;
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.3);
}

.section-image img {
    width: 100%;
    height: 500px;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.section-image:hover img {
    transform: scale(1.05);
}

.section-text h2 {
    font-size: 42px;
    color: var(--snow-white);
    margin-bottom: 25px;
    line-height: 1.2;
}

.diagonal-section.reverse .section-text h2,
.diagonal-section.light .section-text h2 {
    color: var(--deep-sea-blue);
}

.section-text p {
    font-size: 18px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 30px;
    line-height: 1.8;
}

.diagonal-section.reverse .section-text p,
.diagonal-section.light .section-text p {
    color: var(--text-light);
}

.btn {
    display: inline-block;
    padding: 15px 35px;
    background: var(--bright-red);
    color: var(--snow-white);
    font-size: 16px;
    font-weight: 600;
    border-radius: 50px;
    border: 2px solid var(--bright-red);
    transition: all 0.3s ease;
}

.btn:hover {
    background: transparent;
    color: var(--bright-red);
    transform: translateY(-3px);
    box-shadow: 0 10px 30px rgba(230, 57, 70, 0.4);
}

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

.btn-outline:hover {
    background: var(--snow-white);
    color: var(--deep-sea-blue);
}

.diagonal-section.reverse .btn-outline {
    border-color: var(--deep-sea-blue);
    color: var(--deep-sea-blue);
}

.diagonal-section.reverse .btn-outline:hover {
    background: var(--deep-sea-blue);
    color: var(--snow-white);
}

/* ========================================
   Hero Banner
   ======================================== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    position: relative;
    background: linear-gradient(135deg, var(--deep-sea-blue) 0%, var(--ocean-blue) 100%);
    padding-top: 80px;
}

.hero::before {
    content: '';
    position: absolute;
    top: 0;
    right: 0;
    width: 50%;
    height: 100%;
    background: url('../images/hero-bg.jpg') center/cover no-repeat;
    clip-path: polygon(40% 0, 100% 0, 100% 100%, 40% 100%);
    opacity: 0.3;
}

.hero-content {
    position: relative;
    z-index: 2;
    max-width: 600px;
}

.hero-title {
    font-size: 56px;
    color: var(--snow-white);
    margin-bottom: 20px;
    line-height: 1.1;
    animation: fadeInUp 1s ease;
}

.hero-subtitle {
    font-size: 20px;
    color: rgba(255, 255, 255, 0.9);
    margin-bottom: 40px;
    animation: fadeInUp 1s ease 0.2s both;
}

.hero-buttons {
    display: flex;
    gap: 20px;
    animation: fadeInUp 1s ease 0.4s both;
}

/* ========================================
   卡片样式
   ======================================== */
.card-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
    margin-top: 50px;
}

.card {
    background: var(--snow-white);
    border-radius: 20px;
    overflow: hidden;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.1);
    transition: all 0.4s ease;
}

.card:hover {
    transform: translateY(-10px);
    box-shadow: 0 20px 60px rgba(0, 0, 0, 0.15);
}

.card-image {
    height: 220px;
    overflow: hidden;
}

.card-image img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.card:hover .card-image img {
    transform: scale(1.1);
}

.card-content {
    padding: 30px;
}

.card-title {
    font-size: 22px;
    color: var(--deep-sea-blue);
    margin-bottom: 15px;
}

.card-text {
    color: var(--text-light);
    margin-bottom: 20px;
    line-height: 1.7;
}

.card-meta {
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-size: 14px;
    color: var(--text-light);
}

/* ========================================
   服务特色板块
   ======================================== */
.feature-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 30px;
    margin-top: 50px;
}

.feature-item {
    text-align: center;
    padding: 40px 30px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 20px;
    backdrop-filter: blur(10px);
    transition: all 0.4s ease;
    border: 1px solid rgba(255, 255, 255, 0.2);
}

.feature-item:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateY(-10px);
}

.feature-icon {
    width: 80px;
    height: 80px;
    margin: 0 auto 25px;
    background: var(--bright-red);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.feature-icon img {
    width: 40px;
    height: 40px;
}

.feature-title {
    font-size: 20px;
    color: var(--snow-white);
    margin-bottom: 15px;
}

.feature-text {
    font-size: 15px;
    color: rgba(255, 255, 255, 0.8);
    line-height: 1.6;
}

/* ========================================
   页脚
   ======================================== */
.footer {
    background: var(--deep-sea-blue);
    color: var(--snow-white);
    padding: 80px 0 30px;
}

.footer-content {
    display: grid;
    grid-template-columns: 2fr 1fr 1fr 1fr;
    gap: 50px;
    margin-bottom: 50px;
}

.footer-logo {
    font-size: 28px;
    font-weight: 700;
    margin-bottom: 20px;
}

.footer-desc {
    color: rgba(255, 255, 255, 0.7);
    line-height: 1.8;
    margin-bottom: 25px;
}

.footer-social {
    display: flex;
    gap: 15px;
}

.footer-social a {
    width: 40px;
    height: 40px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.3s ease;
}

.footer-social a:hover {
    background: var(--bright-red);
    transform: translateY(-3px);
}

.footer-title {
    font-size: 18px;
    margin-bottom: 25px;
    color: var(--bright-red);
}

.footer-links li {
    margin-bottom: 12px;
}

.footer-links a {
    color: rgba(255, 255, 255, 0.7);
    transition: all 0.3s ease;
}

.footer-links a:hover {
    color: var(--bright-red);
    padding-left: 5px;
}

.footer-contact li {
    margin-bottom: 15px;
    color: rgba(255, 255, 255, 0.7);
    display: flex;
    align-items: center;
    gap: 10px;
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 30px;
    text-align: center;
    color: rgba(255, 255, 255, 0.5);
}

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

.fade-in {
    opacity: 0;
    transform: translateY(30px);
    transition: all 0.6s ease;
}

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

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 1200px) {
    .feature-grid {
        grid-template-columns: repeat(2, 1fr);
    }
    
    .footer-content {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 992px) {
    .section-content {
        grid-template-columns: 1fr;
        gap: 40px;
    }
    
    .section-image {
        order: -1;
    }
    
    .hero-title {
        font-size: 42px;
    }
    
    .nav-menu {
        position: fixed;
        top: 80px;
        left: -100%;
        width: 100%;
        height: calc(100vh - 80px);
        background: var(--deep-sea-blue);
        flex-direction: column;
        align-items: center;
        justify-content: center;
        gap: 30px;
        transition: left 0.4s ease;
    }
    
    .nav-menu.active {
        left: 0;
    }
    
    .hamburger {
        display: flex;
    }
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 32px;
    }
    
    .hero-subtitle {
        font-size: 16px;
    }
    
    .section-text h2 {
        font-size: 32px;
    }
    
    .feature-grid {
        grid-template-columns: 1fr;
    }
    
    .footer-content {
        grid-template-columns: 1fr;
        gap: 30px;
    }
    
    .card-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 576px) {
    .hero-buttons {
        flex-direction: column;
    }
    
    .btn {
        width: 100%;
        text-align: center;
    }
}