:root {
    --primary: #FF9F4D;
    --primary-dark: #f28b36;
    --primary-light: rgba(255, 159, 77, 0.1);
    --primary-shadow: rgba(255, 159, 77, 0.2);
    --bg-white: #FFFFFF;
    --bg-light: #f8fafc;
    --border-light: #eef2f6;
    --border-medium: #e2e8f0;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --success: #6FCF97;
    --code-bg: #1e293b;
    --code-keyword: #FF9F4D;
    --code-builtin: #b1e5f7;
    --code-string: #6FCF97;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.04);
    --shadow-md: 0 8px 24px rgba(0,0,0,0.08);
    --shadow-primary: 0 6px 16px var(--primary-shadow);
    --radius-card: 20px;
    --radius-btn: 12px;
    --radius-modal: 24px;
    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-code: 'SF Mono', 'Fira Code', monospace;
}

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

body {
    font-family: var(--font-main);
    color: var(--text-primary);
    background-color: var(--bg-white);
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
}

.container {
    width: 100%;
    max-width: 1280px;
    margin: 0 auto;
    padding: 0 24px;
}

/* 导航栏 */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border-light);
    transition: all 0.2s;
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 70px;
}

.logo {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--primary);
    text-decoration: none;
    letter-spacing: -0.5px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 8px;
    list-style: none;
}

.nav-link {
    padding: 8px 16px;
    font-weight: 500;
    color: var(--text-secondary);
    text-decoration: none;
    border-radius: 30px;
    transition: all 0.2s;
}

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

.nav-link.active {
    color: var(--primary);
    background: var(--primary-light);
}

.nav-btn {
    background: var(--primary);
    color: white !important;
    margin-left: 8px;
}

.nav-btn:hover {
    background: var(--primary-dark);
}

.btn-login {
    background: none;
    border: 1.5px solid var(--primary);
    color: var(--primary);
    padding: 8px 18px;
    border-radius: 30px;
    font-weight: 600;
    font-size: 0.95rem;
    cursor: pointer;
    transition: all 0.2s;
    margin-left: 8px;
}

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

.mobile-toggle {
    display: none;
    flex-direction: column;
    justify-content: space-around;
    width: 28px;
    height: 24px;
    background: none;
    border: none;
    cursor: pointer;
}

.mobile-toggle span {
    width: 100%;
    height: 2.5px;
    background: var(--text-primary);
    border-radius: 4px;
    transition: all 0.3s;
}

/* 用户登录后样式 */
.user-logged-in .btn-login {
    display: none;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 8px;
}

.user-avatar {
    width: 36px;
    height: 36px;
    background: var(--primary-light);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--primary);
    font-weight: 600;
}

/* 英雄区 */
.hero {
    padding: 140px 0 80px;
    background: linear-gradient(135deg, #fff9f2 0%, #ffffff 100%);
}

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

.hero-content {
    flex: 1;
}

.hero-title {
    font-size: 3.8rem;
    font-weight: 800;
    line-height: 1.2;
    letter-spacing: -1.5px;
    margin-bottom: 24px;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 1.2rem;
    color: var(--text-secondary);
    margin-bottom: 36px;
}

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

.btn {
    display: inline-block;
    padding: 12px 28px;
    border-radius: var(--radius-btn);
    font-weight: 600;
    text-decoration: none;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: var(--shadow-primary);
}

.btn-primary:hover {
    background: var(--primary-dark);
    transform: translateY(-2px);
}

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

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

.btn-secondary {
    background: white;
    border: 1px solid var(--border-medium);
    color: var(--text-primary);
}

.btn-secondary:hover {
    border-color: var(--primary);
    background: var(--primary-light);
}

.btn-block {
    width: 100%;
}

.hero-code {
    flex: 1;
    background: var(--code-bg);
    border-radius: 24px;
    padding: 24px;
    box-shadow: var(--shadow-md);
}

.hero-code pre {
    margin: 0;
    overflow-x: auto;
}

.hero-code code {
    font-family: var(--font-code);
    font-size: 1rem;
    line-height: 1.5;
    color: #e2e8f0;
}

.keyword { color: var(--code-keyword); }
.function { color: #e2e8f0; }
.string { color: var(--code-string); }
.builtin { color: var(--code-builtin); }

/* 通用区块 */
.section {
    padding: 80px 0;
}

.bg-light {
    background: var(--bg-light);
}

.section-title {
    font-size: 2.5rem;
    font-weight: 700;
    text-align: center;
    margin-bottom: 16px;
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: 1.1rem;
    text-align: center;
    color: var(--text-muted);
    margin-bottom: 48px;
}

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

.card {
    background: white;
    border-radius: var(--radius-card);
    padding: 32px 24px;
    border: 1px solid var(--border-light);
    box-shadow: var(--shadow-sm);
    transition: all 0.25s;
}

.card:hover {
    box-shadow: var(--shadow-md);
    transform: translateY(-4px);
    border-color: transparent;
}

.card-icon {
    font-size: 2.5rem;
    margin-bottom: 20px;
}

.card h3 {
    font-size: 1.5rem;
    margin-bottom: 12px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.badge {
    font-size: 0.7rem;
    padding: 4px 10px;
    border-radius: 30px;
    background: #f1f5f9;
    color: var(--text-secondary);
}

.badge.hot {
    background: var(--success);
    color: white;
}

.card-footer {
    margin-top: 24px;
}

.card-link {
    color: var(--primary);
    font-weight: 600;
    text-decoration: none;
}

/* 技术头条 */
.news-list {
    display: flex;
    flex-direction: column;
    gap: 20px;
    max-width: 800px;
    margin: 0 auto;
}

.news-item {
    background: white;
    padding: 24px 28px;
    border-radius: 20px;
    border: 1px solid var(--border-light);
    transition: all 0.2s;
}

.news-item:hover {
    box-shadow: var(--shadow-sm);
    border-color: var(--border-medium);
}

.news-content h4 {
    font-size: 1.25rem;
    margin-bottom: 8px;
}

.news-meta {
    font-size: 0.9rem;
    color: var(--text-muted);
    margin-bottom: 8px;
}

.news-desc {
    color: var(--text-secondary);
}

.text-center {
    text-align: center;
    margin-top: 40px;
}

/* 友链 */
.friend-links {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 20px;
    margin-top: 20px;
}

.friend-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    padding: 20px 28px;
    background: white;
    border: 1px solid var(--border-light);
    border-radius: 40px;
    text-decoration: none;
    color: inherit;
    transition: all 0.2s;
}

.friend-card:hover {
    border-color: var(--primary);
    box-shadow: var(--shadow-primary);
}

.friend-name {
    font-weight: 600;
    font-size: 1.1rem;
}

.friend-desc {
    font-size: 0.9rem;
    color: var(--text-muted);
}

/* 页脚 */
.footer {
    background: var(--bg-light);
    border-top: 1px solid var(--border-light);
    padding: 48px 0 24px;
}

.footer-container {
    display: flex;
    flex-wrap: wrap;
    gap: 48px;
    margin-bottom: 40px;
}

.footer-brand h3 {
    font-size: 1.8rem;
    color: var(--primary);
    margin-bottom: 8px;
}

.slogan {
    color: var(--text-muted);
    font-style: italic;
}

.footer-links {
    display: flex;
    flex-wrap: wrap;
    gap: 60px;
}

.link-group h4 {
    margin-bottom: 16px;
    color: var(--text-primary);
}

.link-group ul {
    list-style: none;
}

.link-group li {
    margin-bottom: 10px;
}

.link-group a {
    color: var(--text-secondary);
    text-decoration: none;
}

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

.footer-bottom {
    text-align: center;
    padding-top: 24px;
    border-top: 1px solid var(--border-medium);
    color: var(--text-muted);
    font-size: 0.9rem;
}

/* 模态框 */
.modal {
    display: none;
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 2000;
    align-items: center;
    justify-content: center;
}

.modal.active {
    display: flex;
}

.modal-overlay {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: rgba(0,0,0,0.4);
    backdrop-filter: blur(4px);
}

.modal-container {
    position: relative;
    width: 90%;
    max-width: 420px;
    background: white;
    border-radius: var(--radius-modal);
    box-shadow: var(--shadow-md);
    padding: 28px;
    animation: modalSlide 0.2s;
}

@keyframes modalSlide {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.modal-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 24px;
}

.modal-header h3 {
    font-size: 1.6rem;
}

.modal-close {
    background: none;
    border: none;
    font-size: 2rem;
    cursor: pointer;
    color: var(--text-muted);
}

.auth-tabs {
    display: flex;
    gap: 12px;
    margin-bottom: 24px;
    border-bottom: 1px solid var(--border-light);
    padding-bottom: 12px;
}

.auth-tab {
    background: none;
    border: none;
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-muted);
    cursor: pointer;
    padding: 6px 0;
    position: relative;
}

.auth-tab.active {
    color: var(--primary);
}

.auth-tab.active::after {
    content: '';
    position: absolute;
    bottom: -13px;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--primary);
}

.auth-form {
    display: none;
}

.auth-form.active {
    display: block;
}

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

.form-group label {
    display: block;
    margin-bottom: 6px;
    font-weight: 500;
    color: var(--text-primary);
}

.form-group input {
    width: 100%;
    padding: 12px 16px;
    border: 1.5px solid var(--border-medium);
    border-radius: 12px;
    font-size: 1rem;
    transition: border 0.2s;
}

.form-group input:focus {
    outline: none;
    border-color: var(--primary);
}

.captcha-input {
    display: flex;
    gap: 12px;
}

.captcha-input input {
    flex: 1;
}

.captcha-img {
    width: 100px;
    height: 46px;
    border-radius: 10px;
    border: 1px solid var(--border-medium);
    cursor: pointer;
}

.auth-message {
    margin-top: 16px;
    text-align: center;
    color: #e53e3e;
    font-size: 0.9rem;
}

/* 响应式 */
@media (max-width: 900px) {
    .hero-container {
        flex-direction: column;
    }
    .hero-title {
        font-size: 2.8rem;
    }
    .card-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 768px) {
    .mobile-toggle {
        display: flex;
    }
    .nav-menu {
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        flex-direction: column;
        background: white;
        padding: 20px;
        border-bottom: 1px solid var(--border-light);
        display: none;
    }
    .nav-menu.active {
        display: flex;
    }
    .nav-link {
        width: 100%;
        text-align: center;
    }
    .container {
        padding: 0 16px;
    }
    .hero {
        padding: 120px 0 60px;
    }
    .footer-links {
        gap: 30px;
    }
}
.announcement-section { padding: 0 0 20px; margin-top: -20px; }
.announcement-bar { display: flex; align-items: center; background: linear-gradient(135deg, #fff9f2 0%, #fff 100%); border: 1px solid #eef2f6; border-radius: 50px; padding: 12px 24px; box-shadow: 0 2px 8px rgba(0,0,0,0.04); }
.announcement-icon { font-size: 1.5rem; margin-right: 16px; }
.announcement-slider { flex: 1; overflow: hidden; position: relative; height: 28px; }
.announcement-item { position: absolute; width: 100%; opacity: 0; transition: opacity 0.5s; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
.announcement-item.active { opacity: 1; }
.announcement-item a { color: #0f172a; text-decoration: none; font-weight: 500; }
.announcement-tag { background: rgba(255,159,77,0.1); color: #FF9F4D; padding: 2px 10px; border-radius: 30px; font-size: 0.75rem; margin-right: 12px; }
/* ========== 企业级 UI 优化 ========== */
:root {
    --transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --shadow-hover: 0 20px 30px -10px rgba(255, 159, 77, 0.15);
    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

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

/* 美化滚动条 */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: #f1f1f1; border-radius: 10px; }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }

/* 按钮点击涟漪效果 */
.btn {
    position: relative;
    overflow: hidden;
    transform: translateY(0);
    transition: var(--transition);
}
.btn::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    width: 5px; height: 5px;
    background: rgba(255,255,255,0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%, -50%);
    transform-origin: 50% 50%;
}
.btn:active::after {
    animation: ripple 0.6s ease-out;
}
@keyframes ripple {
    0% { transform: scale(0, 0); opacity: 0.5; }
    100% { transform: scale(40, 40); opacity: 0; }
}

/* 卡片悬浮增强 */
.card, .course-card, .news-item, .ticket-item {
    transition: var(--transition);
    box-shadow: var(--shadow-card);
}
.card:hover, .course-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

/* 表单输入框动效 */
input, textarea, select {
    transition: border 0.2s, box-shadow 0.2s;
}
input:focus, textarea:focus, select:focus {
    box-shadow: 0 0 0 3px rgba(255, 159, 77, 0.2);
}

/* 加载骨架屏 */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 8px;
}
@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}
/* ========== 企业级 UI 优化 ========== */
:root {
    --transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --shadow-hover: 0 20px 30px -10px rgba(255, 159, 77, 0.15);
    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

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

/* 美化滚动条 */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: #f1f1f1; border-radius: 10px; }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }

/* 按钮点击涟漪效果 */
.btn {
    position: relative;
    overflow: hidden;
    transform: translateY(0);
    transition: var(--transition);
}
.btn::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    width: 5px; height: 5px;
    background: rgba(255,255,255,0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%, -50%);
    transform-origin: 50% 50%;
}
.btn:active::after {
    animation: ripple 0.6s ease-out;
}
@keyframes ripple {
    0% { transform: scale(0, 0); opacity: 0.5; }
    100% { transform: scale(40, 40); opacity: 0; }
}

/* 卡片悬浮增强 */
.card, .course-card, .news-item, .ticket-item {
    transition: var(--transition);
    box-shadow: var(--shadow-card);
}
.card:hover, .course-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

/* 表单输入框动效 */
input, textarea, select {
    transition: border 0.2s, box-shadow 0.2s;
}
input:focus, textarea:focus, select:focus {
    box-shadow: 0 0 0 3px rgba(255, 159, 77, 0.2);
}

/* 加载骨架屏 */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 8px;
}
@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}
/* ========== 企业级 UI 优化 ========== */
:root {
    --transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --shadow-hover: 0 20px 30px -10px rgba(255, 159, 77, 0.15);
    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}

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

/* 美化滚动条 */
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: #f1f1f1; border-radius: 10px; }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }

/* 按钮点击涟漪效果 */
.btn {
    position: relative;
    overflow: hidden;
    transform: translateY(0);
    transition: var(--transition);
}
.btn::after {
    content: '';
    position: absolute;
    top: 50%; left: 50%;
    width: 5px; height: 5px;
    background: rgba(255,255,255,0.5);
    opacity: 0;
    border-radius: 100%;
    transform: scale(1, 1) translate(-50%, -50%);
    transform-origin: 50% 50%;
}
.btn:active::after {
    animation: ripple 0.6s ease-out;
}
@keyframes ripple {
    0% { transform: scale(0, 0); opacity: 0.5; }
    100% { transform: scale(40, 40); opacity: 0; }
}

/* 卡片悬浮增强 */
.card, .course-card, .news-item, .ticket-item {
    transition: var(--transition);
    box-shadow: var(--shadow-card);
}
.card:hover, .course-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
}

/* 表单输入框动效 */
input, textarea, select {
    transition: border 0.2s, box-shadow 0.2s;
}
input:focus, textarea:focus, select:focus {
    box-shadow: 0 0 0 3px rgba(255, 159, 77, 0.2);
}

/* 加载骨架屏 */
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%;
    animation: skeleton-loading 1.5s infinite;
    border-radius: 8px;
}
@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}
/* ========== 企业级 UI 优化 ========== */
:root {
    --transition: all 0.3s cubic-bezier(0.25, 0.46, 0.45, 0.94);
    --shadow-hover: 0 20px 30px -10px rgba(255, 159, 77, 0.15);
    --shadow-card: 0 10px 25px -5px rgba(0, 0, 0, 0.05);
}
html { scroll-behavior: smooth; }
::-webkit-scrollbar { width: 8px; height: 8px; }
::-webkit-scrollbar-track { background: #f1f1f1; border-radius: 10px; }
::-webkit-scrollbar-thumb { background: var(--primary); border-radius: 10px; }
::-webkit-scrollbar-thumb:hover { background: var(--primary-dark); }
.btn {
    position: relative; overflow: hidden; transform: translateY(0);
    transition: var(--transition);
}
.btn::after {
    content: ''; position: absolute; top: 50%; left: 50%; width: 5px; height: 5px;
    background: rgba(255,255,255,0.5); opacity: 0; border-radius: 100%;
    transform: scale(1,1) translate(-50%,-50%); transform-origin: 50% 50%;
}
.btn:active::after { animation: ripple 0.6s ease-out; }
@keyframes ripple {
    0% { transform: scale(0,0); opacity: 0.5; }
    100% { transform: scale(40,40); opacity: 0; }
}
.card, .course-card, .news-item, .ticket-item {
    transition: var(--transition); box-shadow: var(--shadow-card);
}
.card:hover, .course-card:hover {
    transform: translateY(-8px); box-shadow: var(--shadow-hover);
}
input, textarea, select { transition: border 0.2s, box-shadow 0.2s; }
input:focus, textarea:focus, select:focus {
    box-shadow: 0 0 0 3px rgba(255, 159, 77, 0.2);
}
.skeleton {
    background: linear-gradient(90deg, #f0f0f0 25%, #e0e0e0 50%, #f0f0f0 75%);
    background-size: 200% 100%; animation: skeleton-loading 1.5s infinite;
    border-radius: 8px;
}
@keyframes skeleton-loading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}