/* ===== 基础变量 - 明日方舟风格 ===== */
:root {
    --primary: #00d4aa;
    --primary-dark: #00b894;
    --primary-light: #00e5b8;
    --secondary: #00b4d8;
    --accent: #ff6b35;
    --bg: #1a1d24;
    --bg-dark: #111318;
    --surface: #242830;
    --surface-light: #2a2f3a;
    --text: #e8e8e8;
    --text-light: #8a8f98;
    --text-lighter: #6a6f7a;
    --border: #3a3f4a;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.3);
    --shadow: 0 4px 6px -1px rgb(0 0 0 / 0.4), 0 2px 4px -2px rgb(0 0 0 / 0.4);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.5), 0 4px 6px -4px rgb(0 0 0 / 0.5);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.5), 0 8px 10px -6px rgb(0 0 0 / 0.5);
    --radius: 2px;
    --radius-lg: 4px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== 重置与基础 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    line-height: 1.6;
    overflow-x: hidden;
}

/* 有侧边栏时启用flex布局 */
body.has-sidebar {
    display: flex;
    min-height: 100vh;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(26, 29, 36, 0.95);
    backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border);
    transition: var(--transition);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 64px;
}

.nav-logo {
    font-size: 1.25rem;
    font-weight: 700;
    color: var(--primary);
    letter-spacing: 0.1em;
    text-transform: uppercase;
}

.nav-menu {
    display: flex;
    gap: 32px;
}

.nav-link {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--text-light);
    transition: var(--transition);
    position: relative;
    letter-spacing: 0.05em;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--primary);
    transition: var(--transition);
    box-shadow: 0 0 8px var(--primary);
}

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

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

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

.bar {
    width: 24px;
    height: 2px;
    background: var(--text);
    transition: var(--transition);
}

/* ===== Hero 区域 ===== */
.hero {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    position: relative;
    background: var(--bg);
    overflow: hidden;
    padding-top: 64px;
}

/* 科技感网格背景 */
.hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(0, 212, 170, 0.03) 1px, transparent 1px),
        linear-gradient(90deg, rgba(0, 212, 170, 0.03) 1px, transparent 1px);
    background-size: 50px 50px;
    pointer-events: none;
}

.hero-content {
    text-align: center;
    z-index: 2;
    padding: 0 24px;
}

.hero-avatar {
    margin-bottom: 24px;
}

.avatar-circle {
    width: 120px;
    height: 120px;
    border-radius: var(--radius);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto;
    box-shadow: 0 0 30px rgba(0, 212, 170, 0.3);
    position: relative;
    overflow: hidden;
}

.avatar-circle::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, transparent 40%, rgba(255,255,255,0.1) 50%, transparent 60%);
}

.avatar-circle span {
    font-size: 3rem;
    font-weight: 700;
    color: var(--bg-dark);
}

.hero-title {
    font-size: 3rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 8px;
    letter-spacing: 0.1em;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-light);
    margin-bottom: 4px;
    letter-spacing: 0.05em;
}

.hero-major {
    font-size: 1rem;
    color: var(--primary);
    font-weight: 500;
    margin-bottom: 24px;
    letter-spacing: 0.05em;
    text-shadow: 0 0 10px rgba(0, 212, 170, 0.3);
}

.hero-tags {
    display: flex;
    gap: 12px;
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: 32px;
}

.tag {
    padding: 6px 16px;
    border-radius: var(--radius);
    background: var(--surface);
    color: var(--primary);
    font-size: 0.875rem;
    font-weight: 500;
    border: 1px solid var(--border);
    transition: var(--transition);
    letter-spacing: 0.05em;
}

.tag:hover {
    border-color: var(--primary);
    box-shadow: 0 0 12px rgba(0, 212, 170, 0.2);
}

.hero-btn {
    display: inline-block;
    padding: 14px 36px;
    border-radius: var(--radius);
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: var(--bg-dark);
    font-weight: 600;
    font-size: 1rem;
    letter-spacing: 0.1em;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
    clip-path: polygon(10px 0, 100% 0, 100% calc(100% - 10px), calc(100% - 10px) 100%, 0 100%, 0 10px);
}

.hero-btn:hover {
    box-shadow: 0 0 20px rgba(0, 212, 170, 0.4);
    filter: brightness(1.1);
}

/* 装饰圆形 - 改为科技感光晕 */
.hero-decoration {
    position: absolute;
    inset: 0;
    pointer-events: none;
    overflow: hidden;
}

.circle {
    position: absolute;
    border-radius: 50%;
    opacity: 0.05;
}

.circle-1 {
    width: 400px;
    height: 400px;
    background: var(--primary);
    top: -100px;
    right: -100px;
    animation: pulse 4s ease-in-out infinite;
}

.circle-2 {
    width: 300px;
    height: 300px;
    background: var(--secondary);
    bottom: -50px;
    left: -50px;
    animation: pulse 5s ease-in-out infinite 1s;
}

.circle-3 {
    width: 200px;
    height: 200px;
    background: var(--accent);
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    animation: pulse 6s ease-in-out infinite 2s;
}

@keyframes pulse {
    0%, 100% { transform: scale(1); opacity: 0.05; }
    50% { transform: scale(1.1); opacity: 0.08; }
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-10px); }
}

/* ===== 课程区域 ===== */
.courses {
    padding: 100px 0;
    background: var(--bg-dark);
    position: relative;
}

.courses::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--primary), transparent);
    opacity: 0.3;
}

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

.section-title {
    font-size: 2.25rem;
    font-weight: 700;
    color: var(--text);
    margin-bottom: 12px;
    letter-spacing: 0.1em;
}

.section-desc {
    font-size: 1.125rem;
    color: var(--text-light);
    letter-spacing: 0.05em;
}

.courses-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(340px, 1fr));
    gap: 24px;
}

.course-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 32px;
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

/* 左侧 accent 色条 */
.course-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary), var(--secondary));
    transform: scaleY(0);
    transition: var(--transition);
}

.course-card:hover {
    transform: translateY(-4px);
    border-color: var(--primary);
    box-shadow: 0 0 20px rgba(0, 212, 170, 0.1);
}

.course-card:hover::before {
    transform: scaleY(1);
}

.course-icon {
    width: 56px;
    height: 56px;
    border-radius: var(--radius);
    background: var(--surface-light);
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 20px;
    color: var(--primary);
    border: 1px solid var(--border);
}

.course-icon svg {
    width: 28px;
    height: 28px;
}

.course-name {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--text);
    margin-bottom: 12px;
    letter-spacing: 0.05em;
}

.course-desc {
    font-size: 0.9375rem;
    color: var(--text-light);
    line-height: 1.7;
    margin-bottom: 24px;
}

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

.course-status {
    padding: 4px 12px;
    border-radius: var(--radius);
    background: rgba(0, 212, 170, 0.1);
    color: var(--primary);
    font-size: 0.8125rem;
    font-weight: 500;
    border: 1px solid rgba(0, 212, 170, 0.2);
}

.status-soon {
    background: rgba(106, 111, 122, 0.1);
    color: var(--text-lighter);
    border-color: rgba(106, 111, 122, 0.2);
}

.course-link {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--primary);
    transition: var(--transition);
    letter-spacing: 0.05em;
}

.course-link:hover {
    color: var(--primary-light);
    text-shadow: 0 0 8px rgba(0, 212, 170, 0.3);
}

.course-placeholder {
    opacity: 0.7;
}

.course-placeholder .course-icon {
    background: var(--surface-light);
    color: var(--text-lighter);
}

.course-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
    margin-bottom: 16px;
}

.course-tag {
    padding: 3px 10px;
    border-radius: var(--radius);
    background: rgba(0, 180, 216, 0.1);
    color: var(--secondary);
    font-size: 0.75rem;
    font-weight: 500;
    border: 1px solid rgba(0, 180, 216, 0.2);
    letter-spacing: 0.05em;
}

/* ===== 关于区域 ===== */
.about {
    padding: 100px 0;
    background: var(--bg);
    position: relative;
}

.about::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 1px;
    background: linear-gradient(90deg, transparent, var(--border), transparent);
}

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

.about-info {
    display: flex;
    flex-direction: column;
    gap: 20px;
}

.info-item {
    display: flex;
    flex-direction: column;
    gap: 4px;
    padding: 16px 20px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.info-item:hover {
    border-color: var(--primary);
    box-shadow: 0 0 12px rgba(0, 212, 170, 0.1);
}

.info-label {
    font-size: 0.8125rem;
    color: var(--text-lighter);
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.1em;
}

.info-value {
    font-size: 1.0625rem;
    color: var(--text);
    font-weight: 600;
    letter-spacing: 0.05em;
}

.about-intro {
    font-size: 1.0625rem;
    color: var(--text-light);
    line-height: 1.8;
}

.about-intro p {
    padding: 24px;
    background: var(--surface);
    border-radius: var(--radius);
    border: 1px solid var(--border);
    border-left: 3px solid var(--primary);
}

/* ===== 页脚 ===== */
.footer {
    padding: 40px 0;
    background: var(--bg-dark);
    text-align: center;
    border-top: 1px solid var(--border);
}

.footer p {
    color: var(--text-lighter);
    font-size: 0.9375rem;
    letter-spacing: 0.05em;
}

.footer p:first-child {
    margin-bottom: 4px;
}

/* ===== 课程页面通用样式 ===== */
.course-page {
    padding-top: 0 !important;
}

.chapter-content-area {
    max-width: 900px;
    margin: 0 auto;
    padding: 40px 32px;
}

.chapter-breadcrumb {
    font-size: 0.875rem;
    color: var(--text-lighter);
    margin-bottom: 24px;
    padding-bottom: 16px;
    border-bottom: 1px solid var(--border);
    letter-spacing: 0.05em;
}

.chapter-breadcrumb a {
    color: var(--primary);
    transition: var(--transition);
}

.chapter-breadcrumb a:hover {
    text-shadow: 0 0 8px rgba(0, 212, 170, 0.3);
}

.knowledge-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 24px;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
}

.knowledge-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    width: 3px;
    height: 100%;
    background: linear-gradient(180deg, var(--primary), var(--secondary));
}

.knowledge-card h3 {
    color: var(--text);
    font-size: 1.125rem;
    font-weight: 600;
    margin-bottom: 16px;
    letter-spacing: 0.05em;
}

.knowledge-card h4 {
    color: var(--text-light);
    font-size: 1rem;
    font-weight: 600;
    margin: 20px 0 12px;
    letter-spacing: 0.05em;
}

.code-block {
    background: var(--bg-dark);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 16px 20px;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    font-size: 0.875rem;
    color: var(--text);
    overflow-x: auto;
    white-space: pre-wrap;
    line-height: 1.7;
    margin: 12px 0;
}

.code-block code {
    color: var(--primary);
}

.resource-list {
    margin: 20px 0;
}

.resource-list h4 {
    color: var(--text-light);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
    letter-spacing: 0.05em;
}

.resource-list ul {
    padding-left: 20px;
}

.resource-list li {
    color: var(--text-light);
    font-size: 0.9375rem;
    line-height: 1.8;
}

.resource-list a {
    color: var(--primary);
    transition: var(--transition);
}

.resource-list a:hover {
    text-shadow: 0 0 8px rgba(0, 212, 170, 0.3);
}

.self-check {
    margin: 20px 0;
}

.self-check h4 {
    color: var(--text-light);
    font-size: 1rem;
    font-weight: 600;
    margin-bottom: 12px;
    letter-spacing: 0.05em;
}

.self-check ol {
    padding-left: 24px;
}

.self-check li {
    color: var(--text-light);
    font-size: 0.9375rem;
    line-height: 1.8;
    margin-bottom: 8px;
}

/* ===== 步骤列表 ===== */
.step-list {
    counter-reset: step;
    list-style: none;
    padding: 0;
}

.step-list li {
    position: relative;
    padding-left: 40px;
    margin-bottom: 16px;
    color: var(--text-light);
    font-size: 0.9375rem;
    line-height: 1.7;
}

.step-list li::before {
    counter-increment: step;
    content: counter(step);
    position: absolute;
    left: 0;
    top: 0;
    width: 28px;
    height: 28px;
    background: var(--surface);
    border: 1px solid var(--primary);
    color: var(--primary);
    font-size: 0.75rem;
    font-weight: 600;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: var(--radius);
}

/* ===== 响应式 ===== */
@media (max-width: 768px) {
    .nav-menu {
        position: fixed;
        top: 64px;
        left: 0;
        right: 0;
        background: var(--bg);
        flex-direction: column;
        padding: 24px;
        gap: 16px;
        border-bottom: 1px solid var(--border);
        transform: translateY(-100%);
        opacity: 0;
        visibility: hidden;
        transition: var(--transition);
    }

    .nav-menu.active {
        transform: translateY(0);
        opacity: 1;
        visibility: visible;
    }

    .hamburger {
        display: flex;
    }

    .hero-title {
        font-size: 2.25rem;
    }

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

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

    .section-title {
        font-size: 1.875rem;
    }

    .chapter-content-area {
        padding: 20px 16px;
    }
}

/* ===== 滚动动画 ===== */
.course-card {
    opacity: 0;
    transform: translateY(30px);
    animation: fadeInUp 0.6s ease forwards;
}

.course-card:nth-child(1) { animation-delay: 0.1s; }
.course-card:nth-child(2) { animation-delay: 0.2s; }
.course-card:nth-child(3) { animation-delay: 0.3s; }
.course-card:nth-child(4) { animation-delay: 0.4s; }
.course-card:nth-child(5) { animation-delay: 0.5s; }
.course-card:nth-child(6) { animation-delay: 0.6s; }

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