第 6 章：综合实战——打造个人主页¶

/* ============================================
   CSS 变量 & 主题系统
   ============================================ */
:root {
    /* 颜色 */
    --primary: #667eea;
    --primary-dark: #5a6fd6;
    --secondary: #764ba2;
    --accent: #f093fb;

    /* 浅色主题 */
    --bg-primary: #ffffff;
    --bg-secondary: #f8f9fa;
    --bg-card: #ffffff;
    --text-primary: #2c3e50;
    --text-secondary: #636e72;
    --text-muted: #b2bec3;
    --border: #e9ecef;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.12);

    /* 尺寸 */
    --header-height: 70px;
    --max-width: 1100px;
    --radius: 12px;
    --radius-sm: 6px;
    --transition: 0.3s ease;
}

/* 深色主题 */
[data-theme="dark"] {
    --bg-primary: #1a1a2e;
    --bg-secondary: #16213e;
    --bg-card: #1f2b47;
    --text-primary: #e4e6eb;
    --text-secondary: #b0b3b8;
    --text-muted: #6c757d;
    --border: #2d3748;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
    --shadow-hover: 0 8px 30px rgba(0, 0, 0, 0.4);
}

/* ============================================
   全局重置
   ============================================ */
*, *::before, *::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth;
    scroll-padding-top: var(--header-height);
}

body {
    font-family: "Microsoft YaHei", "PingFang SC", "Helvetica Neue", sans-serif;
    font-size: 16px;
    line-height: 1.7;
    color: var(--text-primary);
    background-color: var(--bg-primary);
    transition: background-color var(--transition), color var(--transition);
}

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

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

.container {
    max-width: var(--max-width);
    margin: 0 auto;
    padding: 0 24px;
}

.section {
    padding: 80px 0;
}

.section-title {
    font-size: 32px;
    text-align: center;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    margin-bottom: 48px;
    font-size: 17px;
}

/* ============================================
   导航栏
   ============================================ */
.header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: var(--header-height);
    background: var(--bg-primary);
    box-shadow: 0 1px 10px rgba(0, 0, 0, 0.05);
    z-index: 1000;
    transition: background var(--transition), box-shadow var(--transition);
}

.header.scrolled {
    box-shadow: 0 2px 20px rgba(0, 0, 0, 0.1);
}

.nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 100%;
}

.nav-logo {
    font-size: 20px;
    font-weight: 700;
    color: var(--text-primary);
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    list-style: none;
    gap: 32px;
}

.nav-link {
    color: var(--text-secondary);
    font-size: 15px;
    font-weight: 500;
    position: relative;
    padding: 4px 0;
}

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

.nav-link:hover,
.nav-link.active {
    color: var(--primary);
}

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

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

.theme-toggle {
    background: none;
    border: none;
    font-size: 20px;
    cursor: pointer;
    padding: 4px;
    border-radius: 50%;
    transition: transform var(--transition);
}

.theme-toggle:hover {
    transform: rotate(30deg);
}

/* 汉堡菜单（移动端） */
.hamburger {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 4px;
}

.hamburger span {
    display: block;
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: all var(--transition);
}

.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(5px, -5px);
}

/* ============================================
   英雄区
   ============================================ */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    background: linear-gradient(135deg, var(--bg-secondary) 0%, var(--bg-primary) 100%);
    position: relative;
    overflow: hidden;
}

.hero-container {
    display: flex;
    align-items: center;
    gap: 60px;
    width: 100%;
}

.hero-content {
    flex: 1;
}

.hero-greeting {
    font-size: 18px;
    color: var(--primary);
    margin-bottom: 8px;
    font-weight: 500;
}

.hero-name {
    font-size: 52px;
    font-weight: 800;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    margin-bottom: 12px;
    line-height: 1.2;
}

.hero-title {
    font-size: 22px;
    color: var(--text-secondary);
    margin-bottom: 20px;
    min-height: 33px;
}

.typed-cursor {
    animation: blink 0.8s infinite;
    color: var(--primary);
    font-weight: 300;
}

@keyframes blink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

.hero-description {
    font-size: 17px;
    color: var(--text-secondary);
    line-height: 1.8;
    margin-bottom: 32px;
    max-width: 480px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
}

.hero-image {
    flex-shrink: 0;
}

.hero-avatar {
    width: 280px;
    height: 280px;
    border-radius: 50%;
    overflow: hidden;
    border: 4px solid var(--primary);
    box-shadow: 0 0 60px rgba(102, 126, 234, 0.3);
    animation: float 3s ease-in-out infinite;
}

.hero-avatar img {
    width: 100%;
    height: 100%;
    object-fit: cover;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-15px); }
}

.scroll-down {
    position: absolute;
    bottom: 30px;
    left: 50%;
    transform: translateX(-50%);
    width: 30px;
    height: 50px;
    border: 2px solid var(--text-muted);
    border-radius: 15px;
    display: flex;
    justify-content: center;
    padding-top: 8px;
}

.scroll-down span {
    width: 4px;
    height: 8px;
    background: var(--text-muted);
    border-radius: 2px;
    animation: scrollDown 1.5s infinite;
}

@keyframes scrollDown {
    0% { transform: translateY(0); opacity: 1; }
    100% { transform: translateY(12px); opacity: 0; }
}

/* ============================================
   按钮
   ============================================ */
.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    border: 2px solid transparent;
    text-align: center;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 6px 20px rgba(102, 126, 234, 0.4);
}

.btn-outline {
    border-color: var(--primary);
    color: var(--primary);
    background: transparent;
}

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

.btn-small {
    padding: 6px 16px;
    font-size: 13px;
}

.btn-block {
    width: 100%;
}

/* ============================================
   关于我
   ============================================ */
.about {
    background: var(--bg-secondary);
}

.about-content {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 48px;
    align-items: start;
}

.about-text p {
    margin-bottom: 16px;
    color: var(--text-secondary);
    font-size: 16px;
}

.skills h3 {
    font-size: 18px;
    margin-bottom: 16px;
    color: var(--text-primary);
}

.skill-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.skill-tag {
    padding: 6px 16px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 20px;
    font-size: 14px;
    color: var(--text-secondary);
    transition: all var(--transition);
}

.skill-tag:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-2px);
}

/* ============================================
   项目展示
   ============================================ */
.project-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(320px, 1fr));
    gap: 30px;
}

.project-card {
    background: var(--bg-card);
    border-radius: var(--radius);
    overflow: hidden;
    box-shadow: var(--shadow);
    transition: transform var(--transition), box-shadow var(--transition);
}

.project-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-hover);
}

.project-image {
    height: 180px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
}

.project-placeholder {
    font-size: 56px;
    opacity: 0.8;
}

.project-info {
    padding: 24px;
}

.project-info h3 {
    font-size: 18px;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.project-info p {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 16px;
    line-height: 1.6;
}

.project-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin-bottom: 16px;
}

.project-tags span {
    padding: 3px 10px;
    background: var(--bg-secondary);
    border-radius: 4px;
    font-size: 12px;
    color: var(--text-muted);
}

.project-links {
    display: flex;
    gap: 10px;
}

/* ============================================
   联系表单
   ============================================ */
.contact {
    background: var(--bg-secondary);
}

.contact-form {
    max-width: 600px;
    margin: 0 auto;
    background: var(--bg-card);
    padding: 40px;
    border-radius: var(--radius);
    box-shadow: var(--shadow);
}

.form-group {
    margin-bottom: 20px;
}

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 600;
    font-size: 14px;
    color: var(--text-primary);
}

.form-group input,
.form-group textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius-sm);
    font-size: 15px;
    font-family: inherit;
    background: var(--bg-primary);
    color: var(--text-primary);
    transition: border-color var(--transition), box-shadow var(--transition);
}

.form-group input:focus,
.form-group textarea:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(102, 126, 234, 0.15);
}

.form-group input.error,
.form-group textarea.error {
    border-color: #e74c3c;
}

.error-message {
    display: block;
    color: #e74c3c;
    font-size: 13px;
    margin-top: 4px;
    min-height: 18px;
}

/* ============================================
   页脚
   ============================================ */
.footer {
    background: var(--bg-secondary);
    border-top: 1px solid var(--border);
    padding: 30px 0;
}

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

.footer-copy {
    color: var(--text-muted);
    font-size: 14px;
}

.footer-social {
    display: flex;
    gap: 16px;
}

.footer-social a {
    color: var(--text-muted);
    transition: color var(--transition), transform var(--transition);
}

.footer-social a:hover {
    color: var(--primary);
    transform: translateY(-2px);
}

/* ============================================
   返回顶部按钮
   ============================================ */
.back-to-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 44px;
    height: 44px;
    border-radius: 50%;
    background: var(--primary);
    color: white;
    border: none;
    font-size: 20px;
    cursor: pointer;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.4);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all var(--transition);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    background: var(--primary-dark);
    transform: translateY(-3px);
}

/* ============================================
   响应式设计
   ============================================ */

/* 平板端（≤ 1024px） */
@media (max-width: 1024px) {
    .hero-container {
        flex-direction: column-reverse;
        text-align: center;
        gap: 40px;
    }

    .hero-description {
        max-width: 100%;
    }

    .hero-buttons {
        justify-content: center;
    }

    .hero-avatar {
        width: 200px;
        height: 200px;
    }

    .about-content {
        grid-template-columns: 1fr;
        gap: 32px;
    }
}

/* 手机端（≤ 768px） */
@media (max-width: 768px) {
    .section {
        padding: 60px 0;
    }

    .section-title {
        font-size: 26px;
    }

    .hero-name {
        font-size: 36px;
    }

    .hero-title {
        font-size: 18px;
    }

    .hamburger {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: var(--header-height);
        left: 0;
        width: 100%;
        background: var(--bg-primary);
        flex-direction: column;
        align-items: center;
        gap: 0;
        padding: 20px 0;
        box-shadow: 0 4px 20px rgba(0, 0, 0, 0.1);
        transform: translateY(-120%);
        transition: transform var(--transition);
        z-index: 999;
    }

    .nav-menu.active {
        transform: translateY(0);
    }

    .nav-menu li {
        width: 100%;
        text-align: center;
    }

    .nav-link {
        display: block;
        padding: 14px 0;
        font-size: 16px;
    }

    .project-grid {
        grid-template-columns: 1fr;
    }

    .contact-form {
        padding: 24px;
    }

    .footer-content {
        flex-direction: column;
        gap: 16px;
        text-align: center;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 40px;
        height: 40px;
        font-size: 18px;
    }
}