/**
 * 课时云记 - 现代 SaaS 视觉设计系统
 * Version: 2.0.0
 */

:root {
    /* 核心主色与辅助色 */
    --brand-primary: #4f46e5;
    --brand-primary-hover: #4338ca;
    --brand-primary-light: #eef2ff;
    --brand-primary-glow: rgba(79, 70, 229, 0.22);
    
    --brand-secondary: #06b6d4;
    --brand-accent: #f43f5e;
    --brand-success: #10b981;
    --brand-warning: #f59e0b;

    /* 中性色与背景 */
    --slate-900: #0f172a;
    --slate-800: #1e293b;
    --slate-700: #334155;
    --slate-600: #475569;
    --slate-500: #64748b;
    --slate-400: #94a3b8;
    --slate-200: #e2e8f0;
    --slate-100: #f1f5f9;
    --slate-50: #f8fafc;

    --bg-page: #f8fafc;
    --bg-card: #ffffff;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --text-muted: #64748b;
    --border-color: #e2e8f0;

    /* 阴影与圆角 */
    --radius-sm: 8px;
    --radius-md: 14px;
    --radius-lg: 20px;
    --radius-xl: 28px;
    --radius-full: 9999px;

    --shadow-subtle: 0 1px 3px rgba(15, 23, 42, 0.05), 0 1px 2px rgba(15, 23, 42, 0.03);
    --shadow-md: 0 10px 25px -5px rgba(15, 23, 42, 0.06), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
    --shadow-lg: 0 20px 35px -10px rgba(15, 23, 42, 0.08), 0 10px 15px -5px rgba(15, 23, 42, 0.04);
    --shadow-glow: 0 0 40px -10px rgba(79, 70, 229, 0.35);
}

/* 全局基准 */
html {
    scroll-behavior: smooth;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    background-color: var(--bg-page);
    color: var(--text-primary);
    line-height: 1.65;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    overflow-x: hidden;
}

/* 现代毛玻璃导航栏 */
.modern-navbar {
    background-color: rgba(255, 255, 255, 0.85) !important;
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-bottom: 1px solid rgba(226, 232, 240, 0.8);
    transition: all 0.3s ease;
    padding: 14px 0;
    z-index: 1030;
}

.modern-navbar.navbar-scrolled {
    background-color: rgba(255, 255, 255, 0.96) !important;
    box-shadow: 0 4px 20px rgba(15, 23, 42, 0.06);
    padding: 10px 0;
}

.navbar-brand {
    font-size: 1.35rem;
    font-weight: 700;
    color: var(--slate-900) !important;
    letter-spacing: -0.3px;
    display: flex;
    align-items: center;
    gap: 10px;
}

.navbar-brand img {
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(79, 70, 229, 0.15);
}

.brand-badge {
    font-size: 0.72rem;
    font-weight: 600;
    padding: 3px 8px;
    border-radius: var(--radius-full);
    background: linear-gradient(135deg, rgba(79, 70, 229, 0.1), rgba(6, 182, 212, 0.1));
    color: var(--brand-primary);
    border: 1px solid rgba(79, 70, 229, 0.2);
}

.nav-link {
    font-weight: 500;
    font-size: 0.95rem;
    color: var(--slate-600) !important;
    padding: 8px 16px !important;
    transition: all 0.2s ease;
    border-radius: var(--radius-sm);
}

.nav-link:hover, .nav-link.active {
    color: var(--brand-primary) !important;
    background-color: rgba(79, 70, 229, 0.06);
}

/* 按钮体系 */
.btn-modern-login {
    color: var(--slate-700) !important;
    background-color: #ffffff;
    border: 1px solid var(--slate-200);
    padding: 8px 18px;
    border-radius: var(--radius-full);
    font-size: 0.92rem;
    font-weight: 600;
    transition: all 0.25s ease;
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.btn-modern-login:hover {
    color: var(--brand-primary) !important;
    border-color: var(--brand-primary);
    background-color: var(--brand-primary-light);
    box-shadow: 0 2px 10px rgba(79, 70, 229, 0.1);
    transform: translateY(-1px);
}

.btn-modern-primary {
    background: linear-gradient(135deg, var(--brand-primary) 0%, #6366f1 100%);
    color: #ffffff !important;
    border: none;
    padding: 8px 20px;
    border-radius: var(--radius-full);
    font-size: 0.92rem;
    font-weight: 600;
    box-shadow: 0 4px 14px var(--brand-primary-glow);
    transition: all 0.25s ease;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-modern-primary:hover {
    background: linear-gradient(135deg, var(--brand-primary-hover) 0%, #4f46e5 100%);
    box-shadow: 0 6px 20px rgba(79, 70, 229, 0.38);
    transform: translateY(-2px);
}

.btn-modern-secondary {
    background-color: rgba(255, 255, 255, 0.95);
    color: var(--slate-800) !important;
    border: 1px solid var(--slate-200);
    padding: 12px 24px;
    border-radius: var(--radius-full);
    font-size: 0.98rem;
    font-weight: 600;
    transition: all 0.25s ease;
    backdrop-filter: blur(8px);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
}

.btn-modern-secondary:hover {
    background-color: #ffffff;
    color: var(--brand-primary) !important;
    border-color: var(--brand-primary);
    box-shadow: 0 4px 15px rgba(15, 23, 42, 0.08);
    transform: translateY(-2px);
}

.btn-modern-lg {
    padding: 13px 28px;
    font-size: 1.05rem;
}

/* 现代化卡片与 Bento Grid */
.modern-card {
    background-color: var(--bg-card);
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-subtle);
    transition: all 0.3s cubic-bezier(0.16, 1, 0.3, 1);
    position: relative;
    overflow: hidden;
}

.modern-card:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(79, 70, 229, 0.3);
}

.bento-icon-wrapper {
    width: 48px;
    height: 48px;
    border-radius: var(--radius-md);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.35rem;
    margin-bottom: 16px;
}

/* 渐变与文字高光 */
.gradient-text {
    background: linear-gradient(135deg, var(--brand-primary) 0%, #06b6d4 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    display: inline-block;
}

.gradient-text-accent {
    background: linear-gradient(135deg, #f43f5e 0%, #fb923c 100%);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

/* 徽章与标签 */
.pill-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: var(--radius-full);
    font-size: 0.85rem;
    font-weight: 600;
    letter-spacing: 0.2px;
}

.pill-badge-primary {
    background-color: var(--brand-primary-light);
    color: var(--brand-primary);
    border: 1px solid rgba(79, 70, 229, 0.2);
}

.pill-badge-accent {
    background-color: #fff1f2;
    color: var(--brand-accent);
    border: 1px solid rgba(244, 63, 94, 0.2);
}

/* Hero 区域设计 */
.hero-wrapper {
    padding-top: 130px;
    padding-bottom: 70px;
    position: relative;
    background: radial-gradient(circle at 50% 20%, rgba(79, 70, 229, 0.08) 0%, rgba(248, 250, 252, 0) 70%);
}

.hero-title {
    font-size: 2.85rem;
    font-weight: 800;
    line-height: 1.25;
    letter-spacing: -0.8px;
    color: var(--slate-900);
}

@media (max-width: 768px) {
    .hero-title {
        font-size: 2.1rem;
    }
}

.hero-subtitle {
    font-size: 1.15rem;
    color: var(--slate-600);
    max-width: 680px;
    margin: 0 auto;
}

/* 拟态 Dashboard Mockup 窗口 */
.mockup-container {
    max-width: 1000px;
    margin: 45px auto 0;
    perspective: 1200px;
}

.mockup-window {
    background: #ffffff;
    border: 1px solid rgba(226, 232, 240, 0.9);
    border-radius: var(--radius-xl);
    box-shadow: 0 25px 60px -15px rgba(15, 23, 42, 0.12), 0 0 0 1px rgba(15, 23, 42, 0.03);
    overflow: hidden;
    position: relative;
    transform: rotateX(2deg);
    transition: transform 0.4s ease, box-shadow 0.4s ease;
}

.mockup-window:hover {
    transform: rotateX(0deg);
    box-shadow: 0 30px 70px -10px rgba(79, 70, 229, 0.18);
}

.mockup-header {
    background: #f8fafc;
    padding: 12px 18px;
    border-bottom: 1px solid var(--slate-200);
    display: flex;
    align-items: center;
    gap: 8px;
}

.mockup-dot {
    width: 11px;
    height: 11px;
    border-radius: 50%;
    display: inline-block;
}

.mockup-dot-red { background-color: #ef4444; }
.mockup-dot-yellow { background-color: #f59e0b; }
.mockup-dot-green { background-color: #10b981; }

.mockup-body {
    padding: 24px;
    background: linear-gradient(180deg, #ffffff 0%, #f8fafc 100%);
}

.mockup-stat-card {
    background: #ffffff;
    border: 1px solid var(--slate-200);
    border-radius: var(--radius-md);
    padding: 16px;
    box-shadow: var(--shadow-subtle);
}

.mockup-course-item {
    padding: 12px 14px;
    background: #ffffff;
    border-radius: var(--radius-sm);
    border-left: 4px solid var(--brand-primary);
    box-shadow: var(--shadow-subtle);
    margin-bottom: 10px;
}

/* 信任背书条 */
.trust-bar {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 24px 30px;
    box-shadow: var(--shadow-subtle);
    margin-top: -30px;
    position: relative;
    z-index: 2;
}

.trust-item {
    text-align: center;
    padding: 10px 15px;
}

.trust-number {
    font-size: 1.8rem;
    font-weight: 800;
    color: var(--brand-primary);
    line-height: 1.1;
}

.trust-label {
    font-size: 0.85rem;
    color: var(--slate-500);
    margin-top: 4px;
}

/* 场景与板块通用标题 */
.section-tag {
    font-size: 0.85rem;
    font-weight: 700;
    color: var(--brand-primary);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
    display: block;
}

.section-title {
    font-size: 2.1rem;
    font-weight: 800;
    color: var(--slate-900);
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: 1.05rem;
    color: var(--slate-600);
    max-width: 600px;
    margin: 8px auto 0;
}

/* 三端生态卡片 */
.ecosystem-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 30px 26px;
    height: 100%;
    position: relative;
    transition: all 0.3s ease;
}

.ecosystem-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-lg);
    border-color: rgba(79, 70, 229, 0.3);
}

.ecosystem-badge {
    position: absolute;
    top: 20px;
    right: 20px;
}

/* FAQ 手风琴美化 */
.modern-accordion .accordion-item {
    background-color: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-md) !important;
    margin-bottom: 12px;
    overflow: hidden;
}

.modern-accordion .accordion-button {
    font-weight: 600;
    color: var(--slate-800);
    background-color: #ffffff;
    padding: 18px 24px;
    box-shadow: none !important;
}

.modern-accordion .accordion-button:not(.collapsed) {
    color: var(--brand-primary);
    background-color: var(--brand-primary-light);
}

.modern-accordion .accordion-body {
    padding: 18px 24px 22px;
    color: var(--slate-600);
    font-size: 0.95rem;
    line-height: 1.7;
}

/* 底部行动号召 CTA 区域 */
.cta-banner {
    background: linear-gradient(135deg, #1e1b4b 0%, #312e81 50%, #4338ca 100%);
    border-radius: var(--radius-xl);
    padding: 60px 40px;
    color: #ffffff;
    position: relative;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
}

.cta-banner::before {
    content: '';
    position: absolute;
    top: -50%;
    right: -20%;
    width: 400px;
    height: 400px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.25) 0%, rgba(0,0,0,0) 70%);
    border-radius: 50%;
    pointer-events: none;
}

/* 认证注册页面（reg.html）专用双栏布局 */
.auth-page-wrapper {
    min-height: calc(100vh - 120px);
    padding-top: 100px;
    padding-bottom: 50px;
    display: flex;
    align-items: center;
}

.auth-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-xl);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}

.auth-side-banner {
    background: linear-gradient(135deg, #1e1b4b 0%, #3730a3 100%);
    color: #ffffff;
    padding: 45px 35px;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: space-between;
    position: relative;
}

.auth-side-banner::before {
    content: '';
    position: absolute;
    bottom: -20%;
    right: -20%;
    width: 250px;
    height: 250px;
    background: radial-gradient(circle, rgba(6, 182, 212, 0.3) 0%, rgba(0,0,0,0) 70%);
    border-radius: 50%;
}

.auth-feature-list li {
    margin-bottom: 16px;
    display: flex;
    align-items: flex-start;
    gap: 12px;
    font-size: 0.95rem;
}

.auth-feature-icon {
    width: 24px;
    height: 24px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 0.75rem;
    flex-shrink: 0;
    margin-top: 2px;
}

.form-floating > label {
    color: var(--slate-400);
    font-size: 0.9rem;
}

.form-floating > .form-control:focus ~ label,
.form-floating > .form-control:not(:placeholder-shown) ~ label {
    color: var(--brand-primary);
}

.form-control {
    border: 1px solid var(--slate-200);
    border-radius: var(--radius-sm);
    padding: 12px 14px;
    font-size: 0.95rem;
    transition: all 0.2s ease;
}

.form-control:focus {
    border-color: var(--brand-primary);
    box-shadow: 0 0 0 3px rgba(79, 70, 229, 0.15);
}

/* 注册成功倒计时卡片 */
.success-result-box {
    text-align: center;
    padding: 35px 20px;
    animation: fadeIn 0.4s ease-out;
}

.success-icon-anim {
    width: 76px;
    height: 76px;
    background: #ecfdf5;
    color: var(--brand-success);
    border-radius: 50%;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 2.2rem;
    margin-bottom: 20px;
    box-shadow: 0 4px 20px rgba(16, 185, 129, 0.2);
}

.progress-bar-animated-countdown {
    height: 6px;
    border-radius: 3px;
    background: #e2e8f0;
    overflow: hidden;
    margin: 18px 0;
}

.countdown-fill {
    height: 100%;
    background: linear-gradient(90deg, var(--brand-primary), #06b6d4);
    width: 100%;
    transition: width 1s linear;
}

/* 帮助文档中心（help.html）专用现代化排版 */
.doc-page-wrapper {
    padding-top: 100px;
    padding-bottom: 60px;
    min-height: calc(100vh - 80px);
}

.doc-sidebar {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 20px 14px;
    position: sticky;
    top: 95px;
    box-shadow: var(--shadow-subtle);
}

.doc-group-title {
    font-size: 0.78rem;
    font-weight: 700;
    text-transform: uppercase;
    color: var(--slate-400);
    letter-spacing: 0.5px;
    padding: 10px 12px 6px;
    margin-top: 10px;
}

.doc-nav-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 9px 14px;
    border-radius: var(--radius-sm);
    color: var(--slate-700);
    text-decoration: none;
    font-size: 0.92rem;
    font-weight: 500;
    transition: all 0.2s ease;
    margin-bottom: 3px;
}

.doc-nav-item:hover {
    background-color: var(--slate-100);
    color: var(--brand-primary);
}

.doc-nav-item.active {
    background-color: var(--brand-primary-light);
    color: var(--brand-primary);
    font-weight: 600;
}

.doc-content-card {
    background: #ffffff;
    border: 1px solid var(--border-color);
    border-radius: var(--radius-lg);
    padding: 36px 40px;
    box-shadow: var(--shadow-subtle);
    min-height: 580px;
}

.doc-article h2 {
    font-size: 1.6rem;
    font-weight: 700;
    color: var(--slate-900);
    margin-top: 25px;
    margin-bottom: 14px;
    padding-bottom: 8px;
    border-bottom: 1px solid var(--slate-100);
}

.doc-article h3 {
    font-size: 1.25rem;
    font-weight: 600;
    color: var(--slate-800);
    margin-top: 20px;
    margin-bottom: 10px;
}

.doc-callout {
    padding: 16px 20px;
    border-left: 4px solid var(--brand-primary);
    background-color: #f8faff;
    border-radius: 0 var(--radius-sm) var(--radius-sm) 0;
    margin: 18px 0;
    font-size: 0.92rem;
    color: var(--slate-700);
}

.doc-callout-warning {
    border-left-color: var(--brand-warning);
    background-color: #fffbeb;
}

.doc-step-card {
    border: 1px solid var(--slate-200);
    border-radius: var(--radius-md);
    padding: 16px 20px;
    margin-bottom: 14px;
    background: #ffffff;
}

.doc-step-num {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    background: var(--brand-primary-light);
    color: var(--brand-primary);
    font-weight: 700;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    font-size: 0.85rem;
    margin-right: 10px;
}

/* 骨架屏 Skeleton */
.skeleton-line {
    height: 16px;
    background: linear-gradient(90deg, #f1f5f9 25%, #e2e8f0 50%, #f1f5f9 75%);
    background-size: 200% 100%;
    animation: skeletonLoading 1.5s infinite;
    border-radius: 4px;
    margin-bottom: 12px;
}

.skeleton-title {
    height: 28px;
    width: 45%;
    margin-bottom: 24px;
}

@keyframes skeletonLoading {
    0% { background-position: 200% 0; }
    100% { background-position: -200% 0; }
}

/* 页脚样式 */
.modern-footer {
    background-color: #ffffff;
    border-top: 1px solid var(--border-color);
    color: var(--slate-600);
    padding: 60px 0 30px;
}

.footer-brand h4 {
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--slate-900);
    margin-bottom: 12px;
}

.footer-heading {
    font-size: 0.95rem;
    font-weight: 700;
    color: var(--slate-900);
    text-transform: uppercase;
    letter-spacing: 0.5px;
    margin-bottom: 20px;
}

.footer-links {
    list-style: none;
    padding: 0;
    margin: 0;
}

.footer-links li {
    margin-bottom: 10px;
}

.footer-links a {
    color: var(--slate-500);
    text-decoration: none;
    font-size: 0.92rem;
    transition: color 0.2s ease;
}

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

.footer-bottom {
    margin-top: 50px;
    padding-top: 25px;
    border-top: 1px solid var(--slate-100);
    font-size: 0.86rem;
    color: var(--slate-400);
}

/* 联系我们弹窗 */
.contact-modal-dialog {
    max-width: 420px;
}

.contact-card-body {
    text-align: center;
    padding: 30px;
}

.contact-qr-img {
    width: 200px;
    height: 200px;
    max-width: 100%;
    aspect-ratio: 1 / 1;
    object-fit: contain;
    border-radius: 12px;
    padding: 8px;
    background: #ffffff;
    border: 1px solid var(--slate-200);
    box-shadow: 0 4px 16px rgba(0,0,0,0.06);
    margin: 10px auto;
    display: inline-block;
}

/* 动效与动画 */
@keyframes float {
    0%, 100% { transform: translateY(0px); }
    50% { transform: translateY(-8px); }
}

.animate-float {
    animation: float 4s ease-in-out infinite;
}

@keyframes pulseGlow {
    0%, 100% { opacity: 0.4; transform: scale(1); }
    50% { opacity: 0.7; transform: scale(1.05); }
}

.glow-bg {
    position: absolute;
    border-radius: 50%;
    filter: blur(80px);
    pointer-events: none;
    z-index: 0;
    animation: pulseGlow 6s ease-in-out infinite alternate;
}