/* ===== CSS 变量定义 ===== */
:root {
    /* 主色调 */
    --primary-gradient: linear-gradient(135deg, #FF9800 0%, #9C27B0 100%);
    --secondary-gradient: linear-gradient(135deg, #9C27B0 0%, #FF9800 100%);
    --accent-gradient: linear-gradient(135deg, #FFB74D 0%, #FFA726 100%);

    /* 颜色 */
    --primary-color: #FF9800;
    --secondary-color: #9C27B0;
    --accent-color: #FFB74D;
    --success-color: #10b981;
    --warning-color: #f59e0b;
    --error-color: #ef4444;

    /* 中性色 - 明亮主题 */
    --bg-primary: #f8fafc;
    --bg-secondary: #ffffff;
    --bg-tertiary: #f1f5f9;
    --text-primary: #1e293b;
    --text-secondary: #475569;
    --text-muted: #94a3b8;

    /* 玻璃态效果 */
    --glass-bg: rgba(255, 255, 255, 0.8);
    --glass-border: rgba(148, 163, 184, 0.2);

    /* 间距 */
    --spacing-xs: 0.5rem;
    --spacing-sm: 1rem;
    --spacing-md: 1.5rem;
    --spacing-lg: 2rem;
    --spacing-xl: 3rem;
    --spacing-2xl: 4rem;

    /* 圆角 */
    --radius-sm: 0.5rem;
    --radius-md: 1rem;
    --radius-lg: 1.5rem;
    --radius-full: 9999px;

    /* 阴影 */
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --shadow-xl: 0 20px 25px -5px rgb(0 0 0 / 0.1);
    --shadow-glow: 0 0 20px rgba(255, 152, 0, 0.5);

    /* 过渡 */
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* ===== 基础样式 ===== */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

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

ul {
    list-style: none;
}

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

/* ===== 容器 ===== */
.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 var(--spacing-lg);
}

/* ===== 导航栏 ===== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    background: #ffffff;
    border-bottom: 1px solid #e2e8f0;
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.08);
}

.nav-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0.75rem var(--spacing-lg);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    font-size: 1.5rem;
    font-weight: 700;
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    cursor: pointer;
}

.logo i {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    font-size: 1.8rem;
}

.nav-links {
    display: flex;
    gap: 0.25rem;
    align-items: center;
}

.nav-links > li {
    list-style: none;
}

.nav-links a {
    display: inline-block;
    color: #334155;
    font-weight: 500;
    font-size: 0.9375rem;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    transition: all 0.2s ease;
    text-decoration: none;
}

.nav-links a:hover {
    color: #FF9800;
    background-color: #fff7ed;
}

.nav-links a.active,
.nav-links li a.active {
    color: #ffffff !important;
    background: linear-gradient(135deg, #FF9800 0%, #F57C00 100%) !important;
    font-weight: 600;
}

/* 导航栏按钮 */
.nav-links .btn {
    padding: 0.5rem 1rem;
    font-size: 0.875rem;
}

.nav-links .btn-secondary {
    background: #f8fafc;
    border: 1px solid #e2e8f0;
    color: #334155;
}

.nav-links .btn-secondary:hover {
    background: #f1f5f9;
    border-color: #cbd5e1;
}

.nav-links .btn-primary {
    background: linear-gradient(135deg, #FF9800 0%, #F57C00 100%);
    color: white;
    border: none;
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    color: #334155;
    font-size: 1.5rem;
    cursor: pointer;
}

/* ===== Hero 区域 ===== */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    padding-top: 80px;
    overflow: hidden;
}

.hero-background {
    position: absolute;
    inset: 0;
    overflow: hidden;
}

.gradient-orb {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    opacity: 0.3;
    animation: float 20s ease-in-out infinite;
}

.orb-1 {
    width: 500px;
    height: 500px;
    background: radial-gradient(circle, #FF9800 0%, transparent 70%);
    top: -250px;
    left: -250px;
    animation-delay: 0s;
}

.orb-2 {
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, #9C27B0 0%, transparent 70%);
    top: 50%;
    right: -300px;
    animation-delay: -7s;
}

.orb-3 {
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, #FFB74D 0%, transparent 70%);
    bottom: -200px;
    left: 50%;
    animation-delay: -14s;
}

@keyframes float {
    0%, 100% {
        transform: translate(0, 0) scale(1);
    }
    33% {
        transform: translate(50px, -50px) scale(1.1);
    }
    66% {
        transform: translate(-50px, 50px) scale(0.9);
    }
}

.hero-content {
    position: relative;
    z-index: 1;
    text-align: center;
    max-width: 900px;
    padding: var(--spacing-xl) var(--spacing-lg);
}

.hero-title {
    font-size: clamp(2.5rem, 6vw, 4rem);
    font-weight: 800;
    line-height: 1.2;
    margin-bottom: var(--spacing-md);
}

.gradient-text {
    background: var(--primary-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero-subtitle {
    font-size: clamp(1rem, 2vw, 1.25rem);
    color: var(--text-secondary);
    margin-bottom: var(--spacing-xl);
    line-height: 1.8;
}

.hero-buttons {
    display: flex;
    gap: var(--spacing-md);
    justify-content: center;
    flex-wrap: wrap;
    margin-bottom: var(--spacing-2xl);
}

.hero-stats {
    display: flex;
    gap: var(--spacing-xl);
    justify-content: center;
    flex-wrap: wrap;
    padding-top: var(--spacing-xl);
    border-top: 1px solid var(--glass-border);
}

.stat-item {
    text-align: center;
}

.stat-number {
    font-size: 2rem;
    font-weight: 700;
    background: var(--accent-gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.stat-label {
    color: var(--text-muted);
    font-size: 0.875rem;
    margin-top: var(--spacing-xs);
}

/* ===== 按钮 ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: var(--spacing-xs);
    padding: 0.875rem 2rem;
    border-radius: var(--radius-full);
    font-weight: 600;
    font-size: 1rem;
    border: none;
    cursor: pointer;
    transition: var(--transition);
    text-align: center;
}

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

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-xl), var(--shadow-glow);
}

.btn-secondary {
    background: var(--glass-bg);
    color: var(--text-primary);
    border: 1px solid var(--glass-border);
    backdrop-filter: blur(10px);
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.15);
    transform: translateY(-2px);
}

.btn-large {
    padding: 1.25rem 3rem;
    font-size: 1.125rem;
}

.btn-sm {
    padding: 0.5rem 1.25rem;
    font-size: 0.875rem;
}

/* ===== 用户信息与导航栏 ===== */
.user-info-container {
    position: relative;
}

.user-info {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.375rem;
    cursor: pointer;
    border-radius: 2rem;
    transition: all 0.2s ease;
    background: transparent;
    border: none;
}

.user-info:hover {
    background: #f1f5f9;
}

.user-avatar {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: linear-gradient(135deg, #FF9800 0%, #F57C00 100%);
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
    font-size: 0.9375rem;
    flex-shrink: 0;
}

.user-info .fa-chevron-down {
    font-size: 0.75rem;
    color: #64748b;
    transition: transform 0.2s ease;
}

.user-info:hover .fa-chevron-down {
    color: #334155;
}

.user-dropdown {
    position: absolute;
    top: calc(100% + 0.5rem);
    right: 0;
    background: white;
    border: 1px solid #e2e8f0;
    border-radius: 0.75rem;
    box-shadow: 0 10px 40px rgba(0, 0, 0, 0.12);
    min-width: 240px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(-8px);
    transition: all 0.2s ease;
    overflow: hidden;
}

.user-dropdown.show {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

/* 下拉菜单顶部用户信息 */
.dropdown-user-header {
    padding: 1rem 1.25rem;
    background: #f8fafc;
    border-bottom: 1px solid #e2e8f0;
}

.dropdown-user-name {
    font-size: 0.9375rem;
    font-weight: 600;
    color: #1e293b;
    margin-bottom: 0.25rem;
}

.dropdown-user-credits {
    display: flex;
    align-items: center;
    gap: 0.375rem;
    font-size: 0.875rem;
    color: #FF9800;
    font-weight: 500;
}

.dropdown-user-credits i {
    font-size: 0.875rem;
}

/* 下拉菜单项 */
.user-dropdown a,
.user-dropdown button {
    display: flex;
    align-items: center;
    gap: 0.75rem;
    width: 100%;
    padding: 0.75rem 1.25rem;
    border: none;
    background: none;
    color: #334155;
    font-size: 0.875rem;
    font-weight: 500;
    text-align: left;
    cursor: pointer;
    transition: all 0.15s ease;
    text-decoration: none;
}

.user-dropdown a:hover,
.user-dropdown button:hover {
    background: #fff7ed;
    color: #FF9800;
}

.user-dropdown a i,
.user-dropdown button i {
    width: 18px;
    text-align: center;
    color: #64748b;
    font-size: 0.875rem;
}

.user-dropdown a:hover i,
.user-dropdown button:hover i {
    color: #FF9800;
}

.user-dropdown .divider {
    height: 1px;
    background: #e2e8f0;
    margin: 0.5rem 0;
}

.user-dropdown button.logout {
    color: #dc2626;
}

.user-dropdown button.logout:hover {
    background: #fef2f2;
    color: #dc2626;
}

.user-dropdown button.logout i {
    color: #dc2626;
}

/* ===== 特性区域 ===== */
.features {
    padding: var(--spacing-2xl) 0;
    background: var(--bg-primary);
}

.section-title {
    text-align: center;
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 700;
    margin-bottom: var(--spacing-md);
}

.section-subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-2xl);
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-2xl);
}

.feature-card {
    position: relative;
    background: var(--bg-secondary);
    backdrop-filter: blur(10px);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    transition: var(--transition);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.feature-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(255, 152, 0, 0.2);
}

.feature-card.featured {
    background: linear-gradient(135deg, rgba(255, 152, 0, 0.1) 0%, rgba(156, 39, 176, 0.1) 100%);
    border-color: var(--primary-color);
}

.feature-badge {
    position: absolute;
    top: -12px;
    right: var(--spacing-lg);
    background: var(--primary-gradient);
    color: white;
    padding: 0.25rem 1rem;
    border-radius: var(--radius-full);
    font-size: 0.75rem;
    font-weight: 600;
}

.feature-icon {
    width: 60px;
    height: 60px;
    background: var(--primary-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.5rem;
    margin-bottom: var(--spacing-md);
    color: white;
}

.feature-card h3 {
    font-size: 1.5rem;
    margin-bottom: var(--spacing-sm);
}

.feature-card > p {
    color: var(--text-secondary);
    margin-bottom: var(--spacing-md);
}

.feature-list {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-xs);
}

.feature-list li {
    display: flex;
    align-items: center;
    gap: var(--spacing-xs);
    color: var(--text-secondary);
    font-size: 0.875rem;
}

.feature-list i {
    color: var(--success-color);
    font-size: 0.875rem;
}

/* ===== 使用场景 ===== */
.use-cases {
    padding: var(--spacing-2xl) 0;
}

.use-cases-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: var(--spacing-lg);
    margin-top: var(--spacing-xl);
}

.use-case-card {
    background: var(--bg-secondary);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-lg);
    padding: var(--spacing-xl);
    text-align: center;
    transition: var(--transition);
    box-shadow: 0 1px 3px rgba(0, 0, 0, 0.05);
}

.use-case-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: 0 10px 30px rgba(255, 152, 0, 0.15);
}

.use-case-image {
    width: 80px;
    height: 80px;
    background: var(--primary-gradient);
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto var(--spacing-md);
    font-size: 2rem;
    color: white;
}

.use-case-card h3 {
    font-size: 1.25rem;
    margin-bottom: var(--spacing-xs);
}

.use-case-card p {
    color: var(--text-secondary);
    font-size: 0.875rem;
}

/* ===== CTA 区域 ===== */
.cta-section {
    padding: var(--spacing-2xl) var(--spacing-lg);
    background: linear-gradient(135deg, rgba(255, 152, 0, 0.05) 0%, rgba(156, 39, 176, 0.05) 100%);
    border-top: 1px solid var(--glass-border);
    border-bottom: 1px solid var(--glass-border);
}

.cta-content {
    text-align: center;
    max-width: 600px;
    margin: 0 auto;
}

.cta-content h2 {
    font-size: clamp(2rem, 4vw, 2.5rem);
    margin-bottom: var(--spacing-md);
}

.cta-content p {
    color: var(--text-secondary);
    font-size: 1.125rem;
    margin-bottom: var(--spacing-xl);
}

/* ===== 页脚 ===== */
.footer {
    padding: var(--spacing-2xl) 0 var(--spacing-lg);
    background: var(--bg-secondary);
    border-top: 1px solid var(--glass-border);
}

.footer-content {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: var(--spacing-xl);
    margin-bottom: var(--spacing-xl);
}

.footer-section h3,
.footer-section h4 {
    margin-bottom: var(--spacing-md);
    color: var(--text-primary);
}

.footer-section p,
.footer-section a {
    color: var(--text-muted);
    font-size: 0.875rem;
}

.footer-section ul {
    display: flex;
    flex-direction: column;
    gap: var(--spacing-sm);
}

.footer-section a:hover {
    color: var(--primary-color);
}

.social-links {
    display: flex;
    gap: var(--spacing-md);
}

.social-links a {
    width: 40px;
    height: 40px;
    background: var(--glass-bg);
    border: 1px solid var(--glass-border);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.25rem;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--primary-gradient);
    border-color: transparent;
    transform: translateY(-2px);
}

.footer-bottom {
    padding-top: var(--spacing-lg);
    border-top: 1px solid var(--glass-border);
    text-align: center;
    color: var(--text-muted);
    font-size: 0.875rem;
}

/* ===== 响应式设计 ===== */
@media (max-width: 768px) {
    .nav-links {
        display: none;
    }

    .mobile-menu-btn {
        display: block;
    }

    .hero-buttons {
        flex-direction: column;
        align-items: stretch;
    }

    .hero-stats {
        gap: var(--spacing-md);
    }

    .features-grid,
    .use-cases-grid {
        grid-template-columns: 1fr;
    }
}