/* ========================================
   dzmmai - AI角色聊天创作平台官网样式
   主题：黑金深色风（与应用图标一致）
   ======================================== */

/* CSS变量定义 */
:root {
    --primary: #F59E0B;
    --secondary: #D97706;
    --accent: #FBBF24;
    --gold: #B45309;
    --gradient: linear-gradient(135deg, #FBBF24 0%, #F59E0B 50%, #D97706 100%);
    --gradient-gold: linear-gradient(135deg, #F59E0B 0%, #D97706 100%);
    --gradient-soft: linear-gradient(135deg, rgba(245, 158, 11, 0.15) 0%, rgba(217, 119, 6, 0.15) 100%);
    --bg: #0A0A0F;
    --bg-white: #1A1A1A;
    --bg-card: #141414;
    --text-primary: #F5F5F5;
    --text-secondary: #A3A3A3;
    --text-light: #737373;
    --border: rgba(255, 255, 255, 0.08);
    --border-hover: rgba(245, 158, 11, 0.4);
    --shadow-sm: 0 2px 8px rgba(0, 0, 0, 0.3);
    --shadow-md: 0 8px 24px rgba(0, 0, 0, 0.4);
    --shadow-lg: 0 16px 48px rgba(0, 0, 0, 0.5);
    --radius-sm: 8px;
    --radius-md: 16px;
    --radius-lg: 24px;
    --radius-xl: 32px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* 重置样式 */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif;
    font-size: 16px;
    line-height: 1.6;
    color: var(--text-primary);
    background: var(--bg);
    overflow-x: hidden;
}

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

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

ul {
    list-style: none;
}

button {
    border: none;
    background: none;
    cursor: pointer;
    font-family: inherit;
}

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

/* 渐变文字 */
.gradient-text {
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

/* ========================================
   按钮样式
   ======================================== */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px 28px;
    border-radius: 50px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
    border: 2px solid transparent;
}

.btn-primary {
    background: var(--gradient);
    color: #0A0A0F;
    box-shadow: 0 4px 16px rgba(245, 158, 11, 0.35);
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 8px 28px rgba(245, 158, 11, 0.5);
}

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

.btn-outline:hover {
    background: var(--gradient);
    color: #0A0A0F;
    border-color: transparent;
    transform: translateY(-2px);
}

.btn-lg {
    padding: 16px 36px;
    font-size: 17px;
}

.btn-xl {
    padding: 20px 48px;
    font-size: 19px;
}

.btn-sm {
    padding: 10px 20px;
    font-size: 14px;
}

.download-icon {
    font-size: 1.2em;
    font-weight: bold;
}

/* ========================================
   导航栏
   ======================================== */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    padding: 16px 0;
    transition: var(--transition);
    background: rgba(10, 10, 15, 0.8);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
}

.navbar.scrolled {
    padding: 10px 0;
    background: rgba(20, 20, 20, 0.95);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
    border-bottom-color: var(--border);
}

.nav-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 800;
    font-size: 22px;
}

.logo-img {
    width: 40px;
    height: 40px;
    border-radius: 12px;
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.35);
    object-fit: cover;
}

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

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

.nav-link {
    font-size: 15px;
    font-weight: 500;
    color: var(--text-secondary);
    position: relative;
}

.nav-link::after {
    content: '';
    position: absolute;
    bottom: -4px;
    left: 0;
    width: 0;
    height: 2px;
    background: var(--gradient);
    transition: var(--transition);
    border-radius: 2px;
}

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

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

.nav-download {
    padding: 10px 24px;
    font-size: 14px;
}

.menu-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    padding: 8px;
}

.menu-toggle span {
    width: 24px;
    height: 2px;
    background: var(--text-primary);
    border-radius: 2px;
    transition: var(--transition);
}

.menu-toggle.active span:nth-child(1) {
    transform: translateY(7px) rotate(45deg);
}

.menu-toggle.active span:nth-child(2) {
    opacity: 0;
}

.menu-toggle.active span:nth-child(3) {
    transform: translateY(-7px) rotate(-45deg);
}

/* ========================================
   Hero区域
   ======================================== */
.hero {
    position: relative;
    padding: 140px 0 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background:
        radial-gradient(ellipse at 20% 20%, rgba(245, 158, 11, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 80% 30%, rgba(217, 119, 6, 0.12) 0%, transparent 50%),
        radial-gradient(ellipse at 50% 80%, rgba(251, 191, 36, 0.08) 0%, transparent 50%);
    z-index: -1;
}

.hero-container {
    display: grid;
    grid-template-columns: 1.1fr 0.9fr;
    gap: 60px;
    align-items: center;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 18px;
    background: rgba(245, 158, 11, 0.12);
    border: 1px solid rgba(245, 158, 11, 0.25);
    border-radius: 50px;
    font-size: 13px;
    font-weight: 600;
    color: #FCD34D;
    margin-bottom: 24px;
}

.badge-dot {
    width: 8px;
    height: 8px;
    background: var(--primary);
    border-radius: 50%;
    animation: pulse 2s infinite;
}

@keyframes pulse {
    0%, 100% { opacity: 1; transform: scale(1); }
    50% { opacity: 0.5; transform: scale(1.3); }
}

.hero-title {
    font-size: 52px;
    font-weight: 900;
    line-height: 1.15;
    margin-bottom: 20px;
    letter-spacing: -1px;
    color: var(--text-primary);
}

.hero-subtitle {
    font-size: 20px;
    font-weight: 600;
    color: var(--text-primary);
    margin-bottom: 12px;
}

.hero-desc {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 32px;
}

.hero-buttons {
    display: flex;
    gap: 16px;
    margin-bottom: 28px;
    flex-wrap: wrap;
}

.hero-meta {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    font-size: 13px;
    color: var(--text-light);
    margin-bottom: 24px;
}

.meta-divider {
    color: var(--border);
}

.hero-tags {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 10px;
}

.tag-label {
    font-size: 14px;
    font-weight: 600;
    color: var(--text-secondary);
}

.tag {
    padding: 6px 14px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: 50px;
    font-size: 13px;
    color: #FCD34D;
    transition: var(--transition);
}

.tag:hover {
    background: var(--gradient);
    color: #0A0A0F;
    border-color: transparent;
    transform: translateY(-2px);
}

/* Hero图片 - 手机模型 */
.hero-image {
    position: relative;
    display: flex;
    justify-content: center;
}

.phone-mockup {
    position: relative;
    width: 300px;
}

.phone-screen {
    position: relative;
    width: 100%;
    aspect-ratio: 9 / 18;
    border-radius: 36px;
    overflow: hidden;
    background: #0A0A0F;
    box-shadow: var(--shadow-lg), 0 0 0 8px rgba(26, 26, 26, 0.9), 0 0 0 10px rgba(245, 158, 11, 0.2);
}

.phone-img {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    object-fit: cover;
    opacity: 0;
    transition: opacity 0.6s ease;
}

.phone-img.active {
    opacity: 1;
}

.phone-indicators {
    display: flex;
    justify-content: center;
    gap: 8px;
    margin-top: 20px;
}

.indicator {
    width: 8px;
    height: 8px;
    border-radius: 50%;
    background: rgba(255, 255, 255, 0.15);
    cursor: pointer;
    transition: var(--transition);
}

.indicator.active {
    width: 24px;
    border-radius: 4px;
    background: var(--gradient);
}

/* 浮动卡片 */
.float-card {
    position: absolute;
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 14px 20px;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    box-shadow: var(--shadow-md);
    animation: float 3s ease-in-out infinite;
}

.float-card-1 {
    top: 15%;
    left: -20px;
    animation-delay: 0s;
}

.float-card-2 {
    bottom: 20%;
    right: -20px;
    animation-delay: 1.5s;
}

@keyframes float {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

.float-icon {
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-soft);
    border-radius: 12px;
    font-size: 22px;
}

.float-text {
    display: flex;
    flex-direction: column;
}

.float-text strong {
    font-size: 15px;
    font-weight: 700;
    color: var(--text-primary);
}

.float-text span {
    font-size: 12px;
    color: var(--text-secondary);
}

/* ========================================
   数据统计
   ======================================== */
.stats {
    padding: 60px 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.stats-grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 32px;
}

.stat-item {
    text-align: center;
    padding: 24px;
}

.stat-number {
    font-size: 48px;
    font-weight: 900;
    background: var(--gradient);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
    line-height: 1;
    display: inline-block;
}

.stat-unit {
    display: inline-block;
    font-size: 24px;
    font-weight: 800;
    color: var(--primary);
    margin-left: 4px;
}

.stat-label {
    font-size: 15px;
    color: var(--text-secondary);
    margin-top: 8px;
    font-weight: 500;
}

/* ========================================
   通用区块标题
   ======================================== */
.section-header {
    text-align: center;
    margin-bottom: 56px;
}

.section-tag {
    display: inline-block;
    padding: 6px 16px;
    background: var(--gradient-soft);
    border-radius: 50px;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 2px;
    color: #FCD34D;
    margin-bottom: 16px;
}

.section-title {
    font-size: 38px;
    font-weight: 800;
    margin-bottom: 16px;
    letter-spacing: -0.5px;
    color: var(--text-primary);
}

.section-desc {
    font-size: 17px;
    color: var(--text-secondary);
    max-width: 600px;
    margin: 0 auto;
}

/* ========================================
   核心功能
   ======================================== */
.features {
    padding: 100px 0;
}

.features-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}

.feature-card {
    padding: 36px 32px;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: var(--transition);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    height: 4px;
    background: var(--gradient);
    transform: scaleX(0);
    transform-origin: left;
    transition: var(--transition);
}

.feature-card:hover {
    transform: translateY(-8px);
    box-shadow: var(--shadow-lg);
    border-color: var(--border-hover);
    background: var(--bg-white);
}

.feature-card:hover::before {
    transform: scaleX(1);
}

.feature-icon {
    width: 60px;
    height: 60px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 18px;
    font-size: 28px;
    margin-bottom: 24px;
}

.icon-blue { background: linear-gradient(135deg, rgba(245, 158, 11, 0.25), rgba(245, 158, 11, 0.1)); }
.icon-gold { background: linear-gradient(135deg, rgba(217, 119, 6, 0.25), rgba(217, 119, 6, 0.1)); }

.feature-title {
    font-size: 20px;
    font-weight: 700;
    margin-bottom: 12px;
    color: var(--text-primary);
}

.feature-desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.7;
}

/* ========================================
   详情区块
   ======================================== */
.detail-section {
    padding: 100px 0;
}

.character-section {
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.worldbook-section {
    background: var(--bg);
}

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

.detail-layout.reverse .detail-image {
    order: 2;
}

.detail-layout.reverse .detail-content {
    order: 1;
}

.detail-image {
    position: relative;
}

.image-frame {
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 4px solid var(--bg-white);
}

.image-frame img {
    width: 100%;
    height: auto;
}

.image-badge {
    position: absolute;
    bottom: 24px;
    right: -16px;
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--gradient);
    color: #0A0A0F;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    box-shadow: 0 8px 24px rgba(245, 158, 11, 0.4);
    animation: float 3s ease-in-out infinite;
}

.badge-gold {
    background: var(--gradient-gold);
    box-shadow: 0 8px 24px rgba(217, 119, 6, 0.4);
    color: #0A0A0F;
}

.detail-title {
    font-size: 36px;
    font-weight: 800;
    margin-bottom: 12px;
    letter-spacing: -0.5px;
    color: var(--text-primary);
}

.detail-subtitle {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 36px;
}

.detail-features {
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin-bottom: 32px;
}

.detail-feature {
    display: flex;
    gap: 16px;
}

.df-icon {
    flex-shrink: 0;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-soft);
    border-radius: 14px;
    font-size: 22px;
}

.df-text h4 {
    font-size: 17px;
    font-weight: 700;
    margin-bottom: 6px;
    color: var(--text-primary);
}

.df-text p {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.6;
}

.detail-tags {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
}

.chip {
    padding: 8px 16px;
    background: rgba(245, 158, 11, 0.1);
    border: 1px solid rgba(245, 158, 11, 0.2);
    border-radius: 50px;
    font-size: 13px;
    font-weight: 500;
    color: #FCD34D;
}

.chip-gold {
    background: rgba(217, 119, 6, 0.1);
    border-color: rgba(217, 119, 6, 0.25);
    color: #FBBF24;
}

/* ========================================
   更新日志
   ======================================== */
.changelog {
    padding: 100px 0;
    background: var(--bg-card);
    border-top: 1px solid var(--border);
    border-bottom: 1px solid var(--border);
}

.changelog-timeline {
    max-width: 800px;
    margin: 0 auto;
    position: relative;
    padding-left: 40px;
}

.changelog-timeline::before {
    content: '';
    position: absolute;
    left: 12px;
    top: 8px;
    bottom: 8px;
    width: 2px;
    background: linear-gradient(to bottom, var(--accent), var(--primary), var(--secondary));
    border-radius: 2px;
}

.changelog-item {
    position: relative;
    margin-bottom: 40px;
    padding: 28px 32px;
    background: var(--bg-white);
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: var(--transition);
}

.changelog-item:last-child {
    margin-bottom: 0;
}

.changelog-item:hover {
    box-shadow: var(--shadow-md);
    transform: translateX(4px);
    border-color: var(--border-hover);
}

.changelog-item::before {
    content: '';
    position: absolute;
    left: -34px;
    top: 36px;
    width: 14px;
    height: 14px;
    background: var(--bg-card);
    border: 3px solid var(--secondary);
    border-radius: 50%;
    z-index: 1;
}

.changelog-item.latest::before {
    background: var(--gradient);
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(245, 158, 11, 0.2);
}

.changelog-version {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 16px;
    flex-wrap: wrap;
}

.version-num {
    font-size: 20px;
    font-weight: 800;
    color: #FCD34D;
}

.version-date {
    font-size: 14px;
    color: var(--text-light);
}

.version-tag {
    padding: 4px 12px;
    background: var(--gradient);
    color: #0A0A0F;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 600;
}

.changelog-list {
    display: flex;
    flex-direction: column;
    gap: 10px;
}

.changelog-list li {
    font-size: 14px;
    color: var(--text-secondary);
    padding-left: 20px;
    position: relative;
    line-height: 1.6;
}

.changelog-list li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 10px;
    width: 6px;
    height: 6px;
    background: var(--secondary);
    border-radius: 50%;
}

.changelog-list li strong {
    color: #FCD34D;
    font-weight: 600;
}

/* ========================================
   下载CTA
   ======================================== */
.download-cta {
    padding: 100px 0;
    position: relative;
    overflow: hidden;
}

.download-cta::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(135deg, #0A0A0F 0%, #1A1A1A 50%, #0A0A0F 100%);
    z-index: -1;
}

.download-cta::after {
    content: '';
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 30%, rgba(245, 158, 11, 0.18) 0%, transparent 40%),
        radial-gradient(circle at 80% 70%, rgba(217, 119, 6, 0.15) 0%, transparent 40%);
    z-index: -1;
}

.cta-content {
    text-align: center;
    color: #fff;
}

.cta-title {
    font-size: 42px;
    font-weight: 900;
    margin-bottom: 16px;
}

.cta-desc {
    font-size: 18px;
    opacity: 0.8;
    margin-bottom: 40px;
    max-width: 600px;
    margin-left: auto;
    margin-right: auto;
}

.download-cta .btn-primary {
    background: var(--gradient);
    color: #0A0A0F;
    box-shadow: 0 8px 32px rgba(245, 158, 11, 0.4);
}

.download-cta .btn-primary:hover {
    transform: translateY(-3px) scale(1.02);
    box-shadow: 0 12px 40px rgba(245, 158, 11, 0.5);
}

.cta-meta {
    display: flex;
    justify-content: center;
    align-items: center;
    flex-wrap: wrap;
    gap: 8px;
    margin-top: 24px;
    font-size: 14px;
    opacity: 0.6;
}

.cta-meta .meta-divider {
    opacity: 0.5;
    color: #fff;
}

/* ========================================
   FAQ
   ======================================== */
.faq {
    padding: 100px 0;
    background: var(--bg);
}

.faq-list {
    max-width: 800px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    overflow: hidden;
    transition: var(--transition);
}

.faq-item:hover {
    border-color: var(--border-hover);
}

.faq-item.active {
    border-color: var(--border-hover);
    background: var(--bg-white);
    box-shadow: var(--shadow-sm);
}

.faq-question {
    width: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 22px 28px;
    font-size: 16px;
    font-weight: 600;
    color: var(--text-primary);
    text-align: left;
    transition: var(--transition);
}

.faq-question:hover {
    color: #FCD34D;
}

.faq-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-soft);
    border-radius: 50%;
    font-size: 18px;
    font-weight: 700;
    color: #FCD34D;
    transition: var(--transition);
}

.faq-item.active .faq-icon {
    background: var(--gradient);
    color: #0A0A0F;
    transform: rotate(45deg);
}

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s ease, padding 0.4s ease;
}

.faq-answer p {
    padding: 0 28px 24px;
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.8;
}

/* ========================================
   页脚
   ======================================== */
.footer {
    background: #060608;
    color: rgba(255, 255, 255, 0.6);
    padding: 72px 0 32px;
    border-top: 1px solid var(--border);
}

.footer-grid {
    display: grid;
    grid-template-columns: 1.5fr 1fr 1fr 1.2fr;
    gap: 48px;
    margin-bottom: 48px;
}

.footer-logo .logo-img {
    box-shadow: 0 4px 12px rgba(245, 158, 11, 0.4);
}

.footer-desc {
    margin-top: 16px;
    font-size: 14px;
    line-height: 1.8;
    max-width: 320px;
}

.footer-title {
    font-size: 16px;
    font-weight: 700;
    color: #fff;
    margin-bottom: 20px;
}

.footer-links {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.footer-links a {
    font-size: 14px;
    color: rgba(255, 255, 255, 0.5);
    transition: var(--transition);
}

.footer-links a:hover {
    color: #FCD34D;
    padding-left: 4px;
}

.footer-download-text {
    font-size: 14px;
    margin-bottom: 16px;
    line-height: 1.6;
}

.footer-bottom {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding-top: 32px;
    border-top: 1px solid rgba(255, 255, 255, 0.08);
    font-size: 13px;
    flex-wrap: wrap;
    gap: 16px;
}

.footer-bottom-links {
    display: flex;
    gap: 24px;
}

.footer-bottom-links a {
    color: rgba(255, 255, 255, 0.4);
}

.footer-bottom-links a:hover {
    color: #FCD34D;
}

/* ========================================
   回到顶部
   ======================================== */
.back-to-top {
    position: fixed;
    bottom: 32px;
    right: 32px;
    width: 48px;
    height: 48px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient);
    color: #0A0A0F;
    border-radius: 50%;
    font-size: 20px;
    box-shadow: 0 4px 20px rgba(245, 158, 11, 0.35);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: var(--transition);
    z-index: 999;
}

.back-to-top.visible {
    opacity: 1;
    visibility: visible;
    transform: translateY(0);
}

.back-to-top:hover {
    transform: translateY(-4px);
    box-shadow: 0 8px 28px rgba(245, 158, 11, 0.5);
}

/* ========================================
   滚动动画
   ======================================== */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.8s ease, transform 0.8s ease;
}

.reveal.visible {
    opacity: 1;
    transform: translateY(0);
}

/* ========================================
   响应式设计
   ======================================== */
@media (max-width: 1024px) {
    .hero-container {
        grid-template-columns: 1fr;
        gap: 60px;
        text-align: center;
    }

    .hero-content {
        order: 1;
    }

    .hero-image {
        order: 2;
    }

    .hero-buttons,
    .hero-tags {
        justify-content: center;
    }

    .hero-meta {
        justify-content: center;
    }

    .features-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .detail-layout,
    .detail-layout.reverse {
        grid-template-columns: 1fr;
        gap: 48px;
    }

    .detail-layout.reverse .detail-image {
        order: 1;
    }

    .detail-layout.reverse .detail-content {
        order: 2;
    }

    .footer-grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 20px;
    }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 280px;
        height: 100vh;
        background: var(--bg-white);
        flex-direction: column;
        padding: 80px 32px 32px;
        gap: 24px;
        box-shadow: -8px 0 32px rgba(0, 0, 0, 0.5);
        transition: right 0.4s ease;
        z-index: 999;
        border-left: 1px solid var(--border);
    }

    .nav-menu.active {
        right: 0;
    }

    .nav-download {
        display: none;
    }

    .menu-toggle {
        display: flex;
        z-index: 1001;
    }

    .hero {
        padding: 120px 0 60px;
    }

    .hero-title {
        font-size: 36px;
    }

    .hero-subtitle {
        font-size: 17px;
    }

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

    .btn-lg {
        width: 100%;
        max-width: 320px;
    }

    .phone-mockup {
        width: 240px;
    }

    .float-card-1 {
        left: 0;
    }

    .float-card-2 {
        right: 0;
    }

    .stats-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 24px;
    }

    .stat-number {
        font-size: 36px;
    }

    .stat-unit {
        font-size: 18px;
    }

    .section-title {
        font-size: 28px;
    }

    .section-desc {
        font-size: 15px;
    }

    .features {
        padding: 72px 0;
    }

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

    .detail-section {
        padding: 72px 0;
    }

    .detail-title {
        font-size: 28px;
    }

    .image-badge {
        right: 8px;
        bottom: 16px;
        padding: 10px 16px;
        font-size: 13px;
    }

    .changelog {
        padding: 72px 0;
    }

    .changelog-timeline {
        padding-left: 28px;
    }

    .changelog-item {
        padding: 20px;
    }

    .changelog-item::before {
        left: -24px;
    }

    .download-cta {
        padding: 72px 0;
    }

    .cta-title {
        font-size: 30px;
    }

    .cta-desc {
        font-size: 15px;
    }

    .btn-xl {
        padding: 16px 36px;
        font-size: 16px;
    }

    .faq {
        padding: 72px 0;
    }

    .faq-question {
        padding: 18px 20px;
        font-size: 15px;
    }

    .faq-answer p {
        padding: 0 20px 20px;
        font-size: 14px;
    }

    .footer {
        padding: 56px 0 24px;
    }

    .footer-grid {
        grid-template-columns: 1fr;
        gap: 36px;
    }

    .footer-bottom {
        flex-direction: column;
        text-align: center;
    }

    .back-to-top {
        bottom: 20px;
        right: 20px;
        width: 44px;
        height: 44px;
    }
}

@media (max-width: 480px) {
    .hero-title {
        font-size: 30px;
    }

    .float-card {
        display: none;
    }

    .stats-grid {
        grid-template-columns: 1fr 1fr;
        gap: 16px;
    }

    .stat-item {
        padding: 16px 8px;
    }

    .stat-number {
        font-size: 30px;
    }

    .hero-tags {
        gap: 8px;
    }

    .tag {
        padding: 5px 10px;
        font-size: 12px;
    }
}