/* ============================================================
   AmoreChat · 浪漫粉紫主题 · 自适应样式
   ============================================================ */

/* ---------- 变量定义 ---------- */
:root {
    --color-primary: #ff4d6d;
    --color-primary-dark: #e23e5e;
    --color-secondary: #ff8fa3;
    --color-accent: #a460d6;
    --color-accent-dark: #7b2cbf;
    --color-deep: #2d0a2e;
    --color-ink: #1a0b1f;
    --color-bg: #fff5f8;
    --color-bg-soft: #ffeef3;
    --color-card: #ffffff;
    --color-muted: #8a6b78;
    --color-border: rgba(255, 77, 109, 0.12);

    --gradient-main: linear-gradient(135deg, #ff4d6d 0%, #a460d6 100%);
    --gradient-soft: linear-gradient(135deg, #ffe0e9 0%, #f3e0ff 100%);
    --gradient-text: linear-gradient(120deg, #ff4d6d, #a460d6);

    --shadow-sm: 0 4px 14px rgba(255, 77, 109, 0.08);
    --shadow-md: 0 12px 32px rgba(164, 96, 214, 0.14);
    --shadow-lg: 0 24px 60px rgba(45, 10, 46, 0.22);

    --radius: 18px;
    --radius-lg: 28px;

    --container: 1180px;
    --ease: cubic-bezier(0.4, 0, 0.2, 1);
}

/* ---------- 基础重置 ---------- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

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

body {
    font-family: "PingFang SC", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    background: var(--color-bg);
    color: var(--color-ink);
    line-height: 1.7;
    overflow-x: hidden;
    -webkit-font-smoothing: antialiased;
}

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

a {
    text-decoration: none;
    color: inherit;
    transition: color 0.3s var(--ease);
}

ul {
    list-style: none;
}

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

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

.hide-mobile {
    display: inline;
}

/* ============================================================
   导航栏
   ============================================================ */
.navbar {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    padding: 16px 0;
    transition: all 0.4s var(--ease);
    background: rgba(255, 245, 248, 0.7);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid transparent;
}

.navbar.scrolled {
    padding: 10px 0;
    background: rgba(255, 255, 255, 0.92);
    box-shadow: 0 6px 24px rgba(255, 77, 109, 0.08);
    border-bottom: 1px solid var(--color-border);
}

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

.nav-logo {
    display: flex;
    align-items: center;
    gap: 10px;
    font-weight: 700;
}

.logo-img {
    width: 38px;
    height: 38px;
    border-radius: 10px;
    background: var(--gradient-main);
    object-fit: cover;
}

.logo-text {
    font-size: 20px;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    letter-spacing: 0.3px;
}

.nav-menu {
    display: flex;
    align-items: center;
    gap: 6px;
}

.nav-link {
    padding: 8px 16px;
    border-radius: 30px;
    font-size: 15px;
    font-weight: 500;
    color: var(--color-ink);
    transition: all 0.3s var(--ease);
}

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

.nav-link.nav-download {
    background: var(--gradient-main);
    color: #fff;
    box-shadow: var(--shadow-sm);
}

.nav-link.nav-download:hover {
    color: #fff;
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    gap: 5px;
    background: none;
    border: none;
    cursor: pointer;
    padding: 8px;
}

.nav-toggle span {
    width: 24px;
    height: 2px;
    background: var(--color-ink);
    border-radius: 2px;
    transition: all 0.3s var(--ease);
}

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

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

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

/* ============================================================
   首屏 Hero
   ============================================================ */
.hero {
    position: relative;
    min-height: 100vh;
    display: flex;
    align-items: center;
    padding: 120px 0 80px;
    overflow: hidden;
}

.hero-bg {
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 20% 20%, rgba(255, 143, 163, 0.45) 0%, transparent 45%),
        radial-gradient(circle at 80% 30%, rgba(164, 96, 214, 0.35) 0%, transparent 45%),
        radial-gradient(circle at 50% 90%, rgba(255, 77, 109, 0.25) 0%, transparent 50%),
        linear-gradient(160deg, #fff5f8 0%, #ffeef3 40%, #f3e0ff 100%);
    z-index: -1;
}

.hero-bg::before {
    content: "";
    position: absolute;
    inset: 0;
    background-image:
        radial-gradient(circle at 1px 1px, rgba(255, 77, 109, 0.15) 1px, transparent 0);
    background-size: 28px 28px;
    opacity: 0.5;
}

.hero-container {
    display: grid;
    grid-template-columns: 1.05fr 1fr;
    gap: 50px;
    align-items: center;
}

.hero-tag {
    display: inline-block;
    padding: 7px 18px;
    background: rgba(255, 255, 255, 0.7);
    border: 1px solid var(--color-border);
    border-radius: 30px;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: 1px;
    color: var(--color-primary);
    margin-bottom: 24px;
    backdrop-filter: blur(6px);
}

.hero-title {
    font-size: clamp(2.2rem, 5vw, 3.6rem);
    font-weight: 800;
    line-height: 1.18;
    letter-spacing: -1px;
    margin-bottom: 24px;
    color: var(--color-deep);
}

.hero-desc {
    font-size: clamp(1rem, 1.6vw, 1.12rem);
    color: var(--color-muted);
    margin-bottom: 30px;
    max-width: 540px;
}

.hero-meta {
    display: inline-flex;
    align-items: center;
    gap: 22px;
    padding: 14px 26px;
    background: rgba(255, 255, 255, 0.75);
    border: 1px solid var(--color-border);
    border-radius: 16px;
    margin-bottom: 34px;
    backdrop-filter: blur(8px);
    box-shadow: var(--shadow-sm);
}

.meta-item {
    display: flex;
    flex-direction: column;
}

.meta-label {
    font-size: 12px;
    color: var(--color-muted);
    letter-spacing: 0.5px;
}

.meta-value {
    font-size: 18px;
    font-weight: 700;
    color: var(--color-primary-dark);
}

.meta-divider {
    width: 1px;
    height: 30px;
    background: var(--color-border);
}

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

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 15px 34px;
    border-radius: 50px;
    font-size: 16px;
    font-weight: 600;
    cursor: pointer;
    border: none;
    transition: all 0.35s var(--ease);
}

.btn-primary {
    background: var(--gradient-main);
    color: #fff;
    box-shadow: 0 10px 28px rgba(255, 77, 109, 0.4);
}

.btn-primary:hover {
    transform: translateY(-3px);
    box-shadow: 0 16px 38px rgba(255, 77, 109, 0.5);
    color: #fff;
}

.btn-ghost {
    background: rgba(255, 255, 255, 0.7);
    color: var(--color-deep);
    border: 1px solid var(--color-border);
}

.btn-ghost:hover {
    background: #fff;
    color: var(--color-primary);
    transform: translateY(-3px);
}

/* ---------- 三张截图叠加动效 ---------- */
.hero-shots {
    position: relative;
    height: 560px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.phone-shot {
    position: absolute;
    width: 220px;
    border-radius: 26px;
    overflow: hidden;
    box-shadow: var(--shadow-lg);
    border: 4px solid #fff;
    background: #fff;
    transition: transform 0.5s var(--ease), box-shadow 0.5s var(--ease);
}

.phone-shot img {
    width: 100%;
    aspect-ratio: 9 / 16;
    object-fit: cover;
    background: var(--gradient-soft);
}

.shot-1 {
    left: 50%;
    transform: translateX(-115%) rotate(-8deg) translateY(20px);
    z-index: 1;
    animation: floatA 6s ease-in-out infinite;
}

.shot-2 {
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%) rotate(0deg);
    z-index: 3;
    width: 240px;
    animation: floatB 6s ease-in-out infinite;
}

.shot-3 {
    left: 50%;
    transform: translateX(15%) rotate(8deg) translateY(20px);
    z-index: 2;
    animation: floatC 6s ease-in-out infinite;
}

.phone-shot:hover {
    z-index: 10;
    transform: translate(-50%, -50%) rotate(0deg) scale(1.06) !important;
    box-shadow: 0 30px 70px rgba(45, 10, 46, 0.3);
}

@keyframes floatA {
    0%, 100% { transform: translateX(-115%) rotate(-8deg) translateY(20px); }
    50%      { transform: translateX(-115%) rotate(-8deg) translateY(0px); }
}

@keyframes floatB {
    0%, 100% { transform: translate(-50%, -50%) rotate(0deg) translateY(0); }
    50%      { transform: translate(-50%, -50%) rotate(0deg) translateY(-12px); }
}

@keyframes floatC {
    0%, 100% { transform: translateX(15%) rotate(8deg) translateY(20px); }
    50%      { transform: translateX(15%) rotate(8deg) translateY(0px); }
}

/* ---------- 滚动提示 ---------- */
.scroll-hint {
    position: absolute;
    bottom: 28px;
    left: 50%;
    transform: translateX(-50%);
    text-align: center;
    color: var(--color-muted);
    font-size: 12px;
    letter-spacing: 1px;
}

.scroll-hint span {
    display: block;
    width: 22px;
    height: 36px;
    margin: 0 auto 8px;
    border: 2px solid var(--color-secondary);
    border-radius: 12px;
    position: relative;
}

.scroll-hint span::after {
    content: "";
    position: absolute;
    top: 7px;
    left: 50%;
    transform: translateX(-50%);
    width: 4px;
    height: 7px;
    background: var(--color-primary);
    border-radius: 3px;
    animation: scrollDot 1.6s infinite;
}

@keyframes scrollDot {
    0% { opacity: 0; transform: translate(-50%, 0); }
    50% { opacity: 1; }
    100% { opacity: 0; transform: translate(-50%, 12px); }
}

/* ============================================================
   通用 Section
   ============================================================ */
.section {
    padding: 100px 0;
    position: relative;
}

.section-head {
    text-align: center;
    max-width: 720px;
    margin: 0 auto 60px;
}

.section-tag {
    display: inline-block;
    font-size: 13px;
    font-weight: 700;
    letter-spacing: 3px;
    color: var(--color-primary);
    margin-bottom: 14px;
    padding: 4px 14px;
    background: var(--color-bg-soft);
    border-radius: 20px;
}

.section-title {
    font-size: clamp(1.8rem, 3.5vw, 2.6rem);
    font-weight: 800;
    color: var(--color-deep);
    margin-bottom: 14px;
    letter-spacing: -0.5px;
}

.section-subtitle {
    font-size: 1.05rem;
    color: var(--color-muted);
}

/* ============================================================
   软件简介
   ============================================================ */
.intro {
    background: linear-gradient(180deg, #fff 0%, var(--color-bg) 100%);
}

.intro-grid {
    display: grid;
    grid-template-columns: 1.3fr 1fr;
    gap: 50px;
    align-items: center;
}

.intro-text p {
    color: #555;
    margin-bottom: 20px;
    font-size: 1.05rem;
}

.intro-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 18px;
    margin-top: 32px;
}

.intro-stats li {
    text-align: center;
    padding: 22px 8px;
    background: var(--color-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: transform 0.3s var(--ease);
}

.intro-stats li:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.intro-stats strong {
    display: block;
    font-size: 1.8rem;
    font-weight: 800;
    background: var(--gradient-text);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.intro-stats .unit {
    font-size: 0.9rem;
    -webkit-text-fill-color: var(--color-primary);
}

.intro-stats span {
    font-size: 13px;
    color: var(--color-muted);
}

.intro-card {
    padding: 40px 32px;
    background: var(--gradient-main);
    border-radius: var(--radius-lg);
    color: #fff;
    box-shadow: var(--shadow-lg);
    position: relative;
    overflow: hidden;
}

.intro-card::before {
    content: "";
    position: absolute;
    top: -40px;
    right: -40px;
    width: 160px;
    height: 160px;
    background: rgba(255, 255, 255, 0.15);
    border-radius: 50%;
}

.intro-card::after {
    content: "";
    position: absolute;
    bottom: -60px;
    left: -30px;
    width: 140px;
    height: 140px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
}

.intro-card-icon {
    font-size: 2.4rem;
    margin-bottom: 18px;
    position: relative;
    z-index: 1;
}

.intro-card h3 {
    font-size: 1.35rem;
    line-height: 1.4;
    margin-bottom: 16px;
    position: relative;
    z-index: 1;
}

.intro-card p {
    opacity: 0.92;
    position: relative;
    z-index: 1;
}

/* ============================================================
   功能优点
   ============================================================ */
.features {
    background: var(--color-bg);
}

.feature-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 26px;
    margin-bottom: 50px;
}

.feature-card {
    padding: 38px 32px;
    background: var(--color-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all 0.4s var(--ease);
    position: relative;
    overflow: hidden;
}

.feature-card::before {
    content: "";
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 4px;
    background: var(--gradient-main);
    transform: scaleX(0);
    transform-origin: left;
    transition: transform 0.4s var(--ease);
}

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

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

.feature-icon {
    font-size: 2.4rem;
    width: 70px;
    height: 70px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: var(--gradient-soft);
    border-radius: 20px;
    margin-bottom: 22px;
}

.feature-card h3 {
    font-size: 1.3rem;
    color: var(--color-deep);
    margin-bottom: 12px;
}

.feature-card p {
    color: var(--color-muted);
    font-size: 1rem;
}

.feature-extra {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.feature-extra-item {
    display: flex;
    gap: 16px;
    padding: 26px;
    background: var(--color-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
}

.feature-extra-item .check {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    background: var(--gradient-main);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
}

.feature-extra-item h4 {
    font-size: 1.05rem;
    color: var(--color-deep);
    margin-bottom: 6px;
}

.feature-extra-item p {
    font-size: 0.92rem;
    color: var(--color-muted);
}

/* ============================================================
   用户评价
   ============================================================ */
.reviews {
    background: linear-gradient(180deg, var(--color-bg) 0%, #fff 100%);
}

.reviews-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 26px;
}

.review-card {
    padding: 34px 28px;
    background: var(--color-card);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    transition: all 0.35s var(--ease);
    display: flex;
    flex-direction: column;
}

.review-card:hover {
    transform: translateY(-6px);
    box-shadow: var(--shadow-md);
}

.review-stars {
    color: #ffb800;
    font-size: 1.1rem;
    letter-spacing: 2px;
    margin-bottom: 16px;
}

.review-text {
    font-size: 1.02rem;
    color: #444;
    font-style: italic;
    margin-bottom: 24px;
    flex-grow: 1;
}

.review-author {
    display: flex;
    align-items: center;
    gap: 14px;
    padding-top: 18px;
    border-top: 1px solid var(--color-border);
}

.review-avatar {
    width: 46px;
    height: 46px;
    border-radius: 50%;
    background: var(--gradient-main);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.review-author strong {
    display: block;
    color: var(--color-deep);
    font-size: 1rem;
}

.review-author span {
    font-size: 0.85rem;
    color: var(--color-muted);
}

/* ============================================================
   常见问题
   ============================================================ */
.faq {
    background: var(--color-bg);
}

.faq-list {
    max-width: 820px;
    margin: 0 auto;
    display: flex;
    flex-direction: column;
    gap: 16px;
}

.faq-item {
    background: var(--color-card);
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    border: 1px solid var(--color-border);
    overflow: hidden;
    transition: all 0.3s var(--ease);
}

.faq-item.active {
    box-shadow: var(--shadow-md);
    border-color: var(--color-secondary);
}

.faq-question {
    width: 100%;
    padding: 22px 26px;
    background: none;
    border: none;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 20px;
    text-align: left;
    font-size: 1.05rem;
    font-weight: 600;
    color: var(--color-deep);
    font-family: inherit;
    transition: color 0.3s var(--ease);
}

.faq-question:hover {
    color: var(--color-primary);
}

.faq-icon {
    flex-shrink: 0;
    width: 28px;
    height: 28px;
    background: var(--gradient-soft);
    color: var(--color-primary);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 18px;
    font-weight: 400;
    transition: transform 0.35s var(--ease);
}

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

.faq-answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.4s var(--ease);
}

.faq-answer p {
    padding: 0 26px 24px;
    color: var(--color-muted);
    font-size: 0.98rem;
}

/* ============================================================
   下载区域
   ============================================================ */
.download {
    position: relative;
    padding: 110px 0;
    background: var(--color-deep);
    overflow: hidden;
    text-align: center;
}

.download::before {
    content: "";
    position: absolute;
    inset: 0;
    background:
        radial-gradient(circle at 25% 30%, rgba(255, 77, 109, 0.45) 0%, transparent 45%),
        radial-gradient(circle at 75% 70%, rgba(164, 96, 214, 0.4) 0%, transparent 45%);
}

.download-container {
    position: relative;
    z-index: 2;
}

.download .section-tag {
    background: rgba(255, 255, 255, 0.12);
    color: var(--color-secondary);
}

.download-title {
    font-size: clamp(2rem, 4vw, 3rem);
    font-weight: 800;
    color: #fff;
    margin-bottom: 18px;
    letter-spacing: -0.5px;
}

.download-desc {
    color: rgba(255, 255, 255, 0.78);
    font-size: 1.1rem;
    margin-bottom: 30px;
}

.download-meta {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 14px 28px;
    margin-bottom: 44px;
    color: rgba(255, 255, 255, 0.85);
    font-size: 0.95rem;
}

.download-meta span {
    padding: 8px 18px;
    background: rgba(255, 255, 255, 0.08);
    border: 1px solid rgba(255, 255, 255, 0.15);
    border-radius: 30px;
    backdrop-filter: blur(4px);
}

.btn-download {
    display: inline-flex;
    align-items: center;
    gap: 18px;
    padding: 20px 48px;
    background: var(--gradient-main);
    color: #fff;
    border-radius: 60px;
    box-shadow: 0 16px 40px rgba(255, 77, 109, 0.5);
    transition: all 0.35s var(--ease);
    position: relative;
    overflow: hidden;
}

.btn-download::after {
    content: "";
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(120deg, transparent, rgba(255, 255, 255, 0.35), transparent);
    transition: left 0.6s var(--ease);
}

.btn-download:hover {
    transform: translateY(-4px) scale(1.02);
    box-shadow: 0 24px 55px rgba(255, 77, 109, 0.65);
    color: #fff;
}

.btn-download:hover::after {
    left: 100%;
}

.btn-download-icon {
    font-size: 1.8rem;
    animation: bounceDown 1.8s ease-in-out infinite;
}

.btn-download-text {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    line-height: 1.2;
}

.btn-download-text small {
    font-size: 0.78rem;
    opacity: 0.85;
    letter-spacing: 1px;
}

.btn-download-text strong {
    font-size: 1.35rem;
    font-weight: 700;
}

@keyframes bounceDown {
    0%, 100% { transform: translateY(0); }
    50%      { transform: translateY(5px); }
}

.download-glow {
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 600px;
    height: 600px;
    background: radial-gradient(circle, rgba(255, 77, 109, 0.3) 0%, transparent 60%);
    z-index: 0;
    pointer-events: none;
}

.download-note {
    margin-top: 22px;
    color: rgba(255, 255, 255, 0.6);
    font-size: 0.88rem;
}

/* ============================================================
   页脚
   ============================================================ */
.footer {
    background: #1a0617;
    color: rgba(255, 255, 255, 0.7);
    padding: 70px 0 0;
}

.footer-container {
    display: grid;
    grid-template-columns: 1.3fr 2fr;
    gap: 50px;
    padding-bottom: 50px;
}

.footer-brand .nav-logo {
    margin-bottom: 18px;
}

.footer-brand p {
    font-size: 0.95rem;
    max-width: 300px;
    line-height: 1.7;
}

.footer-brand .logo-text {
    color: #fff;
    -webkit-text-fill-color: #fff;
}

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

.footer-col h4 {
    color: #fff;
    font-size: 1.05rem;
    margin-bottom: 18px;
}

.footer-col a {
    display: block;
    padding: 6px 0;
    font-size: 0.92rem;
    color: rgba(255, 255, 255, 0.6);
    transition: color 0.3s var(--ease);
}

.footer-col a:hover {
    color: var(--color-secondary);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding: 22px 0;
    text-align: center;
}

.footer-bottom p {
    font-size: 0.85rem;
    color: rgba(255, 255, 255, 0.45);
}

/* ============================================================
   返回顶部
   ============================================================ */
.back-top {
    position: fixed;
    bottom: 30px;
    right: 30px;
    width: 50px;
    height: 50px;
    background: var(--gradient-main);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.4rem;
    font-weight: 700;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(20px);
    transition: all 0.4s var(--ease);
    z-index: 999;
}

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

.back-top:hover {
    transform: translateY(-4px);
    color: #fff;
}

/* ============================================================
   滚动渐入动画
   ============================================================ */
.reveal {
    opacity: 0;
    transform: translateY(40px);
    transition: opacity 0.7s var(--ease), transform 0.7s var(--ease);
}

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

.reveal:nth-child(2) { transition-delay: 0.1s; }
.reveal:nth-child(3) { transition-delay: 0.2s; }
.reveal:nth-child(4) { transition-delay: 0.3s; }

/* ============================================================
   响应式 · 平板
   ============================================================ */
@media (max-width: 980px) {
    .hero-container {
        grid-template-columns: 1fr;
        text-align: center;
        gap: 60px;
    }

    .hero-text {
        order: 2;
    }

    .hero-shots {
        order: 1;
        height: 440px;
    }

    .hero-desc {
        margin-left: auto;
        margin-right: auto;
    }

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

    .intro-grid {
        grid-template-columns: 1fr;
        gap: 40px;
    }

    .intro-card {
        order: -1;
    }

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

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

/* ============================================================
   响应式 · 移动端
   ============================================================ */
@media (max-width: 720px) {
    .container {
        padding: 0 18px;
    }

    .hide-mobile {
        display: none;
    }

    /* 导航折叠 */
    .nav-toggle {
        display: flex;
    }

    .nav-menu {
        position: fixed;
        top: 0;
        right: -100%;
        width: 78%;
        max-width: 320px;
        height: 100vh;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        background: #fff;
        padding: 90px 24px 30px;
        box-shadow: -10px 0 40px rgba(0, 0, 0, 0.12);
        transition: right 0.4s var(--ease);
        z-index: 999;
    }

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

    .nav-menu li {
        width: 100%;
    }

    .nav-link {
        display: block;
        padding: 14px 16px;
        border-radius: 12px;
        font-size: 16px;
    }

    .nav-link.nav-download {
        text-align: center;
        margin-top: 10px;
    }

    /* Hero */
    .hero {
        padding: 100px 0 60px;
    }

    .hero-shots {
        height: 380px;
    }

    .phone-shot {
        width: 150px;
    }

    .shot-2 {
        width: 165px;
    }

    @keyframes floatA {
        0%, 100% { transform: translateX(-110%) rotate(-8deg) translateY(20px); }
        50%      { transform: translateX(-110%) rotate(-8deg) translateY(0px); }
    }

    @keyframes floatC {
        0%, 100% { transform: translateX(10%) rotate(8deg) translateY(20px); }
        50%      { transform: translateX(10%) rotate(8deg) translateY(0px); }
    }

    .hero-meta {
        flex-wrap: wrap;
        gap: 14px;
        padding: 14px 20px;
    }

    .hero-actions {
        flex-direction: column;
        width: 100%;
    }

    .btn {
        width: 100%;
    }

    /* Section */
    .section {
        padding: 70px 0;
    }

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

    .feature-extra {
        grid-template-columns: 1fr;
    }

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

    .footer-links {
        grid-template-columns: 1fr 1fr;
        gap: 24px;
    }

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

    .btn-download {
        padding: 16px 32px;
        gap: 14px;
    }

    .btn-download-text strong {
        font-size: 1.15rem;
    }

    .scroll-hint {
        display: none;
    }
}

@media (max-width: 420px) {
    .intro-stats {
        grid-template-columns: 1fr 1fr;
    }

    .footer-links {
        grid-template-columns: 1fr;
    }
}

/* ============================================================
   动效偏好
   ============================================================ */
@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
        scroll-behavior: auto !important;
    }
}