/* 基本重置和全局样式 */
:root {
    --primary-color: #007bff; /* 主题颜色 - 蓝色 */
    --secondary-color: #6c757d; /* 次要颜色 - 灰色 */
    --background-color: #f8f9fa; /* 页面背景色 */
    --text-color: #333;
    --card-bg: #ffffff;
    --header-bg: #ffffff;
    --footer-bg: #343a40;
    --footer-text: #f8f9fa;
    --highlight-color: #ffc107; /* 强调色 - 黄色 */
    --link-hover-color: #0056b3;
}

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

html {
    scroll-behavior: smooth; /* 平滑滚动 */
}

body {
    font-family: 'Arial', 'Helvetica Neue', Helvetica, sans-serif;
    line-height: 1.6;
    background-color: var(--background-color);
    color: var(--text-color);
    overflow-x: hidden; /* 防止水平滚动条 */
}

.container {
    max-width: 1100px;
    margin: auto;
    padding: 0 20px;
    overflow: hidden; /* 清除浮动 */
}

h1, h2, h3 {
    margin-bottom: 1rem;
    color: var(--text-color);
}

h1 { font-size: 2.8rem; }
h2 { font-size: 2.2rem; text-align: center; margin-bottom: 2rem; padding-top: 2rem;}
h3 { font-size: 1.5rem; }

p {
    margin-bottom: 0.8rem;
}

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

a:hover {
    color: var(--link-hover-color);
}

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

/* 头部和导航 */
header {
    background: var(--header-bg);
    color: var(--text-color);
    padding: 1rem 0;
    position: fixed; /* 固定导航栏 */
    width: 100%;
    top: 0;
    z-index: 1000;
    box-shadow: 0 2px 5px rgba(0,0,0,0.1);
    transition: transform 0.3s ease; /* 平滑隐藏/显示 */
}

header.hidden {
    transform: translateY(-100%); /* 向上隐藏 */
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 1200px;
    margin: auto;
    padding: 0 20px;
}

nav .logo a {
    font-size: 1.8rem;
    font-weight: bold;
    color: var(--primary-color);
}

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

nav .nav-links li {
    margin-left: 25px;
}

nav .nav-links a {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-color);
    transition: color 0.3s ease;
}

nav .nav-links a:hover,
nav .nav-links a.active { /* 可以用 JS 添加 active 类 */
    color: var(--primary-color);
    border-bottom: 2px solid var(--primary-color);
    padding-bottom: 5px;
}

.burger {
    display: none; /* 默认隐藏汉堡菜单 */
    cursor: pointer;
}

.burger div {
    width: 25px;
    height: 3px;
    background-color: var(--text-color);
    margin: 5px;
    transition: all 0.3s ease;
}


/* Hero Section */
#hero {
    background: linear-gradient(rgba(0,0,0,0.5), rgba(0,0,0,0.5)), center center/cover no-repeat;
    background-attachment: fixed;
    color: #fff;
    height: 100vh; /* 全屏高度 */
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    padding: 0 20px;
    margin-top: 0; /* 覆盖 section 的默认 margin-top */
    transition: background-image 0.5s ease; /* 平滑过渡背景图 */
}

#hero .avatar {
    width: 150px;
    height: 150px;
    border-radius: 50%;
    border: 3px solid var(--primary-color);
    margin-bottom: 1.5rem;
    object-fit: cover;
}

#hero h1 {
    font-size: 3.5rem;
    margin-bottom: 0.5rem;
    color: #fff;
}
#hero .highlight {
    color: var(--highlight-color);
}

#hero .subtitle {
    font-size: 1.5rem;
    margin-bottom: 2rem;
    font-weight: 300;
}

.cta-button {
    display: inline-block;
    background: var(--primary-color);
    color: #fff;
    padding: 12px 25px;
    border-radius: 5px;
    font-size: 1.1rem;
    transition: background-color 0.3s ease, transform 0.3s ease;
}

.cta-button:hover {
    background: var(--link-hover-color);
    color: #fff;
    transform: translateY(-3px);
}


/* Section 公共样式 */
section {
    padding: 60px 0;
    margin-top: 60px; /* 为固定导航栏留出空间 */
}
section:first-of-type {
    margin-top: 0; /* hero section 不需要上边距 */
}


/* About Section */
#about .about-content {
    display: flex;
    align-items: center;
    gap: 30px;
}
#about .about-image {
    flex: 1;
    max-width: 350px; /* 限制图片宽度 */
}
#about .about-image img {
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.1);
}
#about .about-text {
    flex: 2;
}


/* Skills Section */
.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 20px;
    text-align: center;
}

.skill-item {
    background: var(--card-bg);
    padding: 25px;
    border-radius: 8px;
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}

.skill-item:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.12);
}

.skill-icon {
    font-size: 2.5rem;
    color: var(--primary-color);
    margin-bottom: 1rem;
}


/* Projects Section */
.projects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 25px;
}

.project-card {
    background: var(--card-bg);
    border-radius: 8px;
    overflow: hidden; /* 确保图片圆角生效 */
    box-shadow: 0 2px 10px rgba(0,0,0,0.08);
    display: flex;
    flex-direction: column;
    transition: transform 0.3s ease, box-shadow 0.3s ease;
}
.project-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 5px 15px rgba(0,0,0,0.12);
}

.project-card img { /* 如果项目卡片有图片 */
    width: 100%;
    height: 200px;
    object-fit: cover;
}

.project-info {
    padding: 20px;
    flex-grow: 1; /* 让信息部分占据剩余空间 */
    display: flex;
    flex-direction: column;
}
.project-info h3 {
    color: var(--primary-color);
}
.project-info p {
    flex-grow: 1; /* 让描述占据更多空间 */
    margin-bottom: 1rem;
}

.project-links {
    margin-top: auto; /* 将链接推到底部 */
}

.project-button {
    display: inline-block;
    padding: 8px 15px;
    margin-right: 10px;
    margin-top: 10px;
    border: 1px solid var(--primary-color);
    color: var(--primary-color);
    border-radius: 5px;
    font-size: 0.9rem;
    transition: background-color 0.3s ease, color 0.3s ease;
}

.project-button:hover {
    background-color: var(--primary-color);
    color: #fff;
}
.project-button.code-button {
    border-color: var(--secondary-color);
    color: var(--secondary-color);
}
.project-button.code-button:hover {
    background-color: var(--secondary-color);
    color: #fff;
}
.project-button i {
    margin-right: 5px;
}

/* Contact Section */
#contact {
    text-align: center;
}
.contact-methods {
    margin-top: 2rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap; /* 确保在小屏幕上换行 */
    gap: 15px;
}
.contact-button {
    background: var(--primary-color);
    color: #fff;
    padding: 10px 20px;
    border-radius: 5px;
    font-size: 1rem;
    transition: background-color 0.3s ease, transform 0.3s ease;
    min-width: 120px; /* 保证按钮宽度一致性 */
}
.contact-button:hover {
    background: var(--link-hover-color);
    color: #fff;
    transform: translateY(-3px);
}
.contact-button i {
    margin-right: 8px;
}


/* Footer */
footer {
    background: var(--footer-bg);
    color: var(--footer-text);
    text-align: center;
    padding: 2rem 0;
    margin-top: 2rem;
}

/* 代码块样式 */
pre, code {
    background-color: #f4f4f4;
    border: 1px solid #ddd;
    border-radius: 4px;
}

pre {
    padding: 15px;
    overflow-x: auto;
    line-height: 1.5;
    margin: 1rem 0;
}

code {
    padding: 2px 6px;
    font-family: 'Courier New', monospace;
    font-size: 0.9rem;
}

pre code {
    background-color: transparent;
    border: none;
    padding: 0;
}

/* Highlight.js 主题样式 */
.hljs {
    background-color: #282c34;
    color: #abb2bf;
    font-family: 'Courier New', monospace;
    border-radius: 4px;
}

.hljs-attr, .hljs-attribute {
    color: #e06c75;
}

.hljs-string {
    color: #98c379;
}

.hljs-number {
    color: #d19a66;
}

.hljs-literal {
    color: #56b6c2;
}

.hljs-title {
    color: #61afef;
}

.hljs-section {
    color: #e06c75;
}

.hljs-keyword {
    color: #c678dd;
}

.hljs-comment {
    color: #5c6370;
    font-style: italic;
}

pre code.hljs {
    background-color: #282c34 !important;
    color: #abb2bf !important;
}

/* 文章容器样式 */
article {
    line-height: 1.8;
    color: #333;
}

article h1 {
    font-size: 2.2rem;
    margin: 2rem 0 1rem 0;
    border-bottom: 3px solid var(--primary-color);
    padding-bottom: 0.5rem;
}

article h2 {
    font-size: 1.8rem;
    margin: 1.5rem 0 1rem 0;
    text-align: left;
    padding-top: 0;
    border-left: 4px solid var(--primary-color);
    padding-left: 1rem;
}

article h3 {
    font-size: 1.3rem;
    margin: 1.2rem 0 0.8rem 0;
    text-align: left;
}

article p {
    margin-bottom: 1rem;
    text-align: justify;
}

article ol, article ul {
    margin-left: 2rem;
    margin-bottom: 1rem;
}

article li {
    margin-bottom: 0.5rem;
}

/* 响应式设计 */
@media (max-width: 768px) {
    nav .nav-links {
        position: absolute;
        right: 0px;
        height: 92vh;
        top: 8vh; /* 假设 header 高度为 8vh */
        background: var(--header-bg);
        display: flex;
        flex-direction: column;
        align-items: center;
        width: 60%;
        transform: translateX(100%); /* 初始隐藏 */
        transition: transform 0.5s ease-in;
        box-shadow: -2px 0px 5px rgba(0,0,0,0.1);
    }

    nav .nav-links.nav-active {
        transform: translateX(0%); /* 显示 */
    }

    nav .nav-links li {
        margin: 20px 0;
        opacity: 0; /* 为动画准备 */
    }

    .burger {
        display: block; /* 在小屏幕上显示汉堡菜单 */
    }

    /* 汉堡菜单动画 */
    .toggle .line1 {
        transform: rotate(-45deg) translate(-5px, 6px);
    }
    .toggle .line2 {
        opacity: 0;
    }
    .toggle .line3 {
        transform: rotate(45deg) translate(-5px, -6px);
    }

    /* 为激活的导航链接添加动画 */
    .nav-active li {
        opacity: 1;
        transition: opacity 0.3s ease forwards;
    }
    .nav-active li:nth-child(1) { transition-delay: 0.1s; }
    .nav-active li:nth-child(2) { transition-delay: 0.2s; }
    .nav-active li:nth-child(3) { transition-delay: 0.3s; }
    .nav-active li:nth-child(4) { transition-delay: 0.4s; }


    #hero h1 {
        font-size: 2.5rem;
    }
    #hero .subtitle {
        font-size: 1.2rem;
    }

    #about .about-content {
        flex-direction: column;
        text-align: center;
    }
    #about .about-image {
        margin-bottom: 1.5rem;
        max-width: 250px; /* 移动端小一点的图片 */
        margin-left: auto;
        margin-right: auto;
    }

    .skills-grid, .projects-grid {
        grid-template-columns: 1fr; /* 单列显示 */
    }
}