/* ============================================================
   全局设计 Token（CSS Variables）
   ============================================================ */
:root {
    /* 色彩体系 */
    --cream: #fffaf2;
    --paper: #fffdf9;
    --ink: #28242d;
    --muted: #716a76;
    --purple: #d7c2ef;
    --purple-strong: #9874bc;
    --yellow: #f7e39b;
    --pink: #f4d9df;
    
    /* 功能色 */
    --line: rgba(45, 41, 50, .14);
    
    /* 布局尺寸 */
    --safe-left: env(safe-area-inset-left, 0px);
    --safe-right: env(safe-area-inset-right, 0px);
    --shell: min(1380px, calc(100% - 48px - var(--safe-left) - var(--safe-right)));
    
    /* 动效曲线 */
    --ease: cubic-bezier(.22, 1, .36, 1);
}

/* ============================================================
   基础重置 & 全局样式
   ============================================================ */
* {
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    margin: 0;
    color: var(--ink);
    background: var(--cream);
    font-family: Inter, "PingFang SC", "Microsoft YaHei", system-ui, sans-serif;
    overflow-x: hidden;
}

body.menu-open {
    overflow: hidden;
}

a {
    color: inherit;
    text-decoration: none;
}

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

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

/* 通用容器 */
.section-shell {
    width: var(--shell);
    margin-inline: auto;
}

/* 滚动进度条 */
.page-progress {
    position: fixed;
    z-index: 100;
    top: 0;
    left: 0;
    width: 100%;
    height: 3px;
}

.page-progress span {
    display: block;
    width: 0;
    height: 100%;
    background: linear-gradient(90deg, var(--purple-strong), #f0b4c6, var(--yellow));
}

/* ============================================================
   站点头部 Header
   ============================================================ */
.site-header {
    position: fixed;
    z-index: 80;
    top: 18px;
    left: 50%;
    width: min(1400px, calc(100% - 32px - var(--safe-left) - var(--safe-right)));
    height: 68px;
    padding: 0 18px 0 22px;
    transform: translateX(-50%);
    
    display: grid;
    grid-template-columns: 1fr auto 1fr;
    align-items: center;
    
    border: 1px solid rgba(255, 255, 255, .65);
    border-radius: 99px;
    background: rgba(255, 253, 249, .78);
    -webkit-backdrop-filter: blur(20px);
    backdrop-filter: blur(20px);
    transition: box-shadow .3s, background .3s;
}

.site-header.scrolled {
    background: rgba(255, 253, 249, .94);
    box-shadow: 0 14px 44px rgba(60, 47, 65, .09);
}

/* Logo 品牌区 */
.brand {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    width: max-content;
    font-size: 20px;
    font-weight: 900;
    letter-spacing: -.04em;
}

.brand img {
    width: 25px;
    height: 25px;
}

.brand b {
    font-size: 12px;
    letter-spacing: 0;
}

/* 桌面端导航 */
.desktop-nav {
    display: flex;
    gap: 30px;
}

.desktop-nav a {
    position: relative;
    font-size: 13px;
    font-weight: 750;
}

.desktop-nav a::after {
    content: "";
    position: absolute;
    left: 0;
    right: 100%;
    bottom: -7px;
    height: 1px;
    background: currentColor;
    transition: right .25s;
}

.desktop-nav a:hover::after {
    right: 0;
}

/* 移动端菜单（默认隐藏） */
.menu-toggle,
.mobile-nav {
    display: none;
}

/* ============================================================
   Hero 首屏区域
   ============================================================ */
.hero {
    position: relative;
    min-height: 100vh;
    min-height: 100svh;
    padding-top: 120px;
    padding-bottom: 50px;
    
    display: grid;
    grid-template-columns: .92fr 1.08fr;
    gap: 70px;
    align-items: center;
}

/* 小标签（Eyebrow）通用样式 */
.eyebrow,
.section-label {
    margin: 0;
    font-size: 11px;
    font-weight: 900;
    letter-spacing: .15em;
}

.eyebrow {
    display: flex;
    gap: 12px;
    align-items: center;
    color: var(--muted);
}

.eyebrow i {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--purple-strong);
    box-shadow: 0 0 0 6px #eadcf5;
}

/* 主标题 */
.hero h1 {
    max-width: 780px;
    margin: 28px 0 0;
    font-size: clamp(50px, 5.0vw, 80px);
    line-height: .98;
    letter-spacing: -.065em;
}

.hero h1 em {
    display: block;
    color: var(--purple-strong);
    font-style: normal;
}

/* 副标题 */
.hero-lead {
    max-width: 640px;
    margin: 30px 0 0;
    color: var(--muted);
    font-size: 18px;
    line-height: 1.82;
}

/* 行动按钮组 */
.hero-actions {
    display: flex;
    align-items: center;
    gap: 14px;
    margin-top: 32px;
}

/* 主按钮 */
.app-button {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    min-height: 58px;
    padding: 0 25px;
    border-radius: 99px;
    background: var(--ink);
    color: #fff;
    font-weight: 850;
    transition: transform .3s var(--ease), box-shadow .3s;
}

.app-button:hover {
    transform: translateY(-3px);
    box-shadow: 0 16px 30px rgba(40, 36, 45, .17);
}

.app-button small {
    display: block;
    font-size: 12px;
    font-weight: 500;
}

.app-icon {
    font-size: 20px;
}

/* 次级按钮 */
.text-button {
    display: inline-flex;
    gap: 28px;
    align-items: center;
    min-height: 58px;
    padding: 0 22px;
    border: 1px solid var(--line);
    border-radius: 99px;
    font-size: 13px;
    font-weight: 800;
    background: rgba(255, 255, 255, .45);
}

/* Hero 视觉区 */
.hero-visual {
    position: relative;
    min-height: 700px;
    display: grid;
    place-items: center;
}

.hero-visual::before {
    content: "";
    position: absolute;
    width: 82%;
    aspect-ratio: 1;
    border-radius: 50%;
    background: radial-gradient(circle at 38% 34%, #fff 0 12%, #fae5eb 34%, #dfccef 64%, rgba(247, 227, 155, .25) 80%);
}

/* 轨道圆环 */
.hero-orbit {
    position: absolute;
    border: 0px solid rgba(154, 120, 191, .2);
    border-radius: 50%;
}

.orbit-a {
    width: 92%;
    aspect-ratio: 1;
}

.orbit-b {
    width: 66%;
    aspect-ratio: 1;
}

/* 产品主体 */
.hero-product {
    position: relative;
    z-index: 2;
    width: min(76%, 570px);
    filter: drop-shadow(0 35px 35px rgba(61, 44, 51, .18));
    animation: productFloat 6s ease-in-out infinite;
}

/* 浮动标签 */
.floating-label {
    position: absolute;
    z-index: 4;
    padding: 10px 16px;
    border: 1px solid rgba(255, 255, 255, .72);
    border-radius: 99px;
    background: rgba(255, 255, 255, .7);
    -webkit-backdrop-filter: blur(12px);
    backdrop-filter: blur(12px);
    box-shadow: 0 14px 34px rgba(70, 55, 74, .09);
    font-size: 13px;
    font-weight: 850;
}

.label-a { left: 2%; top: 22%; }
.label-b { right: 0; top: 38%; }
.label-c { right: 13%; bottom: 14%; }

/* ============================================================
   影片展示区（Film Section）
   ============================================================ */
.film-section {
    padding: 120px 0 100px;
    background: #211e25;
    color: #fff;
}

.film-intro {
    display: grid;
    grid-template-columns: 1fr auto;
    align-items: end;
}

.film-intro .section-label {
    grid-column: 1 / -1;
}

.film-intro h2 {
    margin: 25px 0 0;
    font-size: clamp(48px, 5.3vw, 80px);
    line-height: 1.02;
    letter-spacing: -.06em;
}

.film-intro > p:last-child {
    color: #aba2ad;
}

.light {
    color: #bbb2bd;
}

/* 屏幕容器 */
.film-screen {
    position: relative;
    width: 100%;
    aspect-ratio: 16 / 9;
    margin-top: 52px;
    border-radius: 42px;
    overflow: hidden;
    background: radial-gradient(circle at 66% 35%, #ffe8a3, #cdb0e4 43%, #5a446b 85%);
    box-shadow: 0 45px 100px rgba(0, 0, 0, .25);
}

.film-screen > video {
    display: block;
    width: 100%;
    height: 100%;
    object-fit: cover;
    background: #151217;
}

/* ============================================================
   第一性原理（Principle）
   ============================================================ */
.principle {
    padding-top: 140px;
    padding-bottom: 140px;
}

/* 区块标题通用样式 */
.editorial-heading h2,
.system-heading h2,
.app-story-title h2 {
    margin: 26px 0 70px;
    font-size: clamp(43px, 5.2vw, 77px);
    line-height: 1.06;
    letter-spacing: -.06em;
}

.editorial-heading h2 span {
    color: var(--purple-strong);
}

/* 原理列表 */
.principle-list {
    
}

.principle-item {
    display: grid;
    grid-template-columns: 70px 1fr auto;
    gap: 30px;
    align-items: center;
    padding: 38px 5px;
    transition: padding .35s var(--ease), background .35s;
}

.principle-item:hover {
    padding-left: 22px;
    padding-right: 22px;
    background: rgba(255, 255, 255, .55);
}

.principle-item > span {
    align-self: start;
    color: var(--purple-strong);
    font-size: 11px;
    font-weight: 900;
}

.principle-item h3 {
    margin: 0 0 9px;
    font-size: clamp(23px, 2vw, 31px);
    letter-spacing: -.025em;
}

.principle-item p {
    margin: 0;
    color: var(--muted);
    line-height: 1.7;
}

.principle-item > i {
    font-size: 26px;
    font-style: normal;
}

.promise {
    padding: 130px 0;
    color: var(--ink);
}

.promise-inner {
    display: grid;
    grid-template-columns: .95fr 1.05fr;
    gap: 130px;
    align-items: start;
}

.promise-sticky {
    position: sticky;
    top: 130px;
}

.promise-sticky h2 {
    margin: 25px 0 30px;
    font-size: clamp(42px, 4.7vw, 70px);
    line-height: 1.07;
    letter-spacing: -.055em;
}

.promise-sticky > p:last-child {
    max-width: 520px;
    color: #bdb5bf;
    line-height: 1.8;
}

/* 承诺卡片 */
.promise-cards {
    display: grid;
    gap: 18px;
}

.promise-card {
    min-height: 250px;
    padding: 36px;
    border: 1px solid rgba(255, 255, 255, .13);
    border-radius: 32px;
    background: linear-gradient(135deg, rgba(255, 255, 255, .08), rgba(255, 255, 255, .025));
    transition: transform .4s var(--ease), background .4s;
}

.promise-card:hover {
    transform: translateX(-12px);
    background: linear-gradient(135deg, rgba(215, 194, 239, .16), rgba(255, 255, 255, .035));
}

.promise-card span {
    color: var(--yellow);
    font-size: 11px;
    font-weight: 900;
}

.promise-card h3 {
    margin: 50px 0 14px;
    font-size: 30px;
}

.promise-card p {
    max-width: 460px;
    margin: 0;
    color: #bdb5bf;
    line-height: 1.7;
}

/* ============================================================
   系统闭环（System）
   ============================================================ */
.system {
    padding-top: 140px;
    padding-bottom: 130px;
}

.system-heading {
    display: grid;
    grid-template-columns: 1fr 360px;
    gap: 50px;
    align-items: end;
}

.system-heading h2 {
    margin-bottom: 0;
}

.system-heading > p {
    color: var(--muted);
    line-height: 1.8;
}

/* 系统画布 */
.system-canvas {
    position: relative;
    min-height: 640px;
    margin-top: 75px;
    border-radius: 50px;
    overflow: hidden;
    background: #f0e8f7;
}

/* 同心圆 */
.system-rings i {
    position: absolute;
    left: 50%;
    top: 50%;
    transform: translate(-50%, -50%);
    border: 1px solid rgba(154, 120, 191, .24);
    border-radius: 50%;
}

.system-rings i:nth-child(1) { width: 620px; height: 620px; }
.system-rings i:nth-child(2) { width: 450px; height: 450px; }
.system-rings i:nth-child(3) { width: 290px; height: 290px; }

/* 核心节点 */
.system-core {
    position: absolute;
    z-index: 3;
    left: 50%;
    top: 50%;
    width: 220px;
    height: 220px;
    transform: translate(-50%, -50%);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    background: radial-gradient(circle at 40% 30%, #fff, #c6a9e8 52%, #8562ab);
    color: #111;
    text-align: center;
    box-shadow: 0 25px 70px rgba(113, 75, 150, .34);
}

.system-core img {
    display: block;
    width: 72px;
    height: 72px;
    margin-bottom: 4px;
    object-fit: contain;
    filter: none;
}

.system-core strong {
    display: block;
    width: 100%;
    font-size: 28px;
    line-height: 1.15;
    text-align: center;
}

.system-core small {
    display: block;
    width: 100%;
    margin-top: 8px;
    line-height: 1.5;
    text-align: center;
}

/* 外围节点 */
.system-node {
    position: absolute;
    z-index: 4;
    width: 280px;
    padding: 23px;
    border: 1px solid rgba(154, 120, 191, .22);
    border-radius: 26px;
    background: rgba(255, 255, 255, .82);
    box-shadow: 0 20px 50px rgba(90, 65, 106, .08);
    transition: transform .35s var(--ease);
}

.system-node:hover {
    transform: translateY(-8px);
}

.system-node > span {
    color: var(--purple-strong);
    font-size: 10px;
    font-weight: 900;
}

.system-node h3 {
    margin: 12px 0 7px;
    font-size: 21px;
}

.system-node p {
    margin: 0 0 18px;
    color: var(--muted);
    font-size: 12px;
}

.system-node b {
    font-size: 11px;
}

.node-one { left: 7%; top: 11%; }
.node-two { right: 6%; top: 18%; }
.node-three { right: 13%; bottom: 8%; }

/* 数据循环流 */
.data-loop {
    display: flex;
    justify-content: center;
    align-items: center;
    gap: 21px;
    margin-top: 28px;
}

.data-loop span {
    padding: 12px 20px;
    border: 1px solid var(--line);
    border-radius: 99px;
    font-size: 13px;
}

.data-loop i {
    color: #b6aeb8;
    font-style: normal;
}

/* ============================================================
   App 故事（App Story）
   ============================================================ */
.app-story {
    padding: 140px 0;
}

.app-story-title > p:last-child {
    margin-top: -46px;
    color: var(--muted);
}

.app-story-layout {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 110px;
    align-items: start;
}

/* 手机展示区 */
.phone-stage {
    position: sticky;
    isolation: isolate;
    top: 105px;
    min-height: 760px;
    display: grid;
    place-items: center;
}

.phone-aura {
    position: absolute;
    z-index: 0;
    width: min(610px, 44vw);
    max-width: calc(100vw - 40px);
    aspect-ratio: 1;
    border-radius: 50%;
    background: linear-gradient(135deg, #eadff3, #b898d1);
    opacity: .72;
    transition: background .7s;
}

/* iPhone 样机 */
.iphone {
    position: relative;
    z-index: 2;
    width: 340px;
    height: 700px;
    padding: 9px;
    border: 2px solid #746e76;
    border-radius: 60px;
    background: linear-gradient(145deg, #e9e7e9, #8a858c 28%, #f8f7f8 57%, #79747b);
    box-shadow: 0 45px 90px rgba(56, 45, 61, .28), inset 0 0 0 2px rgba(255, 255, 255, .65);
}

/* 物理按键 */
.phone-buttons {
    position: absolute;
    left: -5px;
    top: 120px;
    display: grid;
    gap: 16px;
}

.phone-buttons i {
    width: 4px;
    height: 36px;
    border-radius: 3px 0 0 3px;
    background: #7e7880;
}

.phone-buttons i:first-child {
    height: 22px;
}

/* 屏幕内容 */
.phone-screen {
    position: relative;
    width: 100%;
    height: 100%;
    overflow: hidden;
    border-radius: 51px;
    background: #fffaf4;
}

.dynamic-island {
    position: absolute;
    z-index: 9;
    top: 11px;
    left: 50%;
    width: 96px;
    height: 27px;
    transform: translateX(-50%);
    border-radius: 20px;
    background: #131216;
}

.phone-status {
    position: relative;
    z-index: 8;
    display: flex;
    justify-content: space-between;
    padding: 16px 24px 10px;
    font-size: 9px;
    font-weight: 800;
}

/* App 顶部栏 */
.app-header {
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 15px 21px 12px;
}

.app-header img {
    width: 29px;
    height: 29px;
}

.app-header span {
    flex: 1;
}

.app-header small,
.app-header b {
    display: block;
}

.app-header small {
    color: #98909a;
    font-size: 8px;
}

.app-header b {
    margin-top: 2px;
    font-size: 11px;
}

.app-header > i {
    font-style: normal;
    color: var(--purple-strong);
}

/* 视图切换 */
.phone-view {
    position: absolute;
    inset: 100px 15px 62px;
    opacity: 0;
    visibility: hidden;
    transform: translateY(22px);
    transition: opacity .5s var(--ease), transform .5s var(--ease), visibility .5s;
}

.phone-view.active {
    opacity: 1;
    visibility: visible;
    transform: none;
}

/* 实时卡片 */
.live-card {
    padding: 13px;
    border-radius: 24px;
    background: #29252e;
    color: #fff;
}

.live-card > span {
    position: absolute;
    padding: 5px 7px;
    border-radius: 8px;
    background: #ea7c8d;
    font-size: 12px;
    font-weight: 900;
}

.crib-visual {
    height: 260px;
    display: grid;
    place-items: center;
    border-radius: 17px;
    background: radial-gradient(circle at 50% 58%, #e8d7f6, #847094 65%, #403746);
    overflow: hidden;
}

.crib-visual i {
    width: 125px;
    height: 78px;
    border-radius: 50% 50% 42% 42%;
    background: #f4dfaa;
    box-shadow: 0 10px 35px rgba(255, 239, 180, .45);
    transform: rotate(-8deg);
}

.crib-visual b {
    position: absolute;
    margin-top: 150px;
    padding: 6px 9px;
    border-radius: 10px;
    background: rgba(33, 29, 38, .7);
    font-size: 8px;
}

.live-card > p {
    margin: 12px 2px 3px;
}

.live-card > p b,
.live-card > p small {
    display: block;
}

.live-card > p b {
    font-size: 22px;
}

.live-card > p small {
    margin-top: 4px;
    color: #bdb4c0;
    font-size: 14px;
}

/* 手机通知 */
.phone-alert {
    display: flex;
    gap: 10px;
    align-items: center;
    margin-top: 10px;
    padding: 13px;
    border-radius: 17px;
    background: #e7f2d9;
}

.phone-alert > i {
    display: grid;
    place-items: center;
    width: 30px;
    height: 30px;
    border-radius: 50%;
    background: #9dca72;
    font-style: normal;
}

.phone-alert b,
.phone-alert small {
    display: block;
}

.phone-alert b {
    font-size: 14px;
}

.phone-alert small {
    margin-top: 3px;
    color: #6d7665;
    font-size: 12px;
}

.view-kicker {
    margin: 7px 0 24px;
    color: var(--purple-strong);
    font-size: 8px;
    font-weight: 900;
    letter-spacing: .15em;
}

/* AI 助手球 */
.assistant-orb {
    display: grid;
    place-items: center;
    width: 120px;
    height: 120px;
    margin: 20px auto;
    border-radius: 50%;
    background: radial-gradient(circle at 35% 30%, #fff, #d7c2ef 48%, #926bb6);
    color: #fff;
    font-size: 30px;
    box-shadow: 0 20px 45px rgba(136, 96, 173, .25);
}

.phone-view h4 {
    margin: 21px 0 13px;
    text-align: center;
    font-size: 24px;
    line-height: 1.15;
    letter-spacing: -.05em;
}

.view-copy {
    color: #766e78;
    text-align: center;
    font-size: 14px;
    line-height: 1.65;
}

.phone-view > button {
    display: block;
    margin: 20px auto 0;
    padding: 11px 16px;
    border: 0;
    border-radius: 99px;
    background: var(--ink);
    color: #fff;
    font-size: 14px;
}

/* 图表 */
.app-chart {
    position: relative;
    height: 210px;
    margin-top: 24px;
    display: flex;
    align-items: end;
    gap: 8px;
    border-bottom: 1px solid #d9d1da;
}

.app-chart i {
    flex: 1;
    border-radius: 12px 12px 0 0;
    background: linear-gradient(#a684c8, #e2d2f1);
}

.app-chart i:nth-child(1) { height: 32%; }
.app-chart i:nth-child(2) { height: 48%; }
.app-chart i:nth-child(3) { height: 40%; }
.app-chart i:nth-child(4) { height: 67%; }
.app-chart i:nth-child(5) { height: 58%; }
.app-chart i:nth-child(6) { height: 78%; }
.app-chart i:nth-child(7) { height: 88%; }

.chart-labels {
    display: flex;
    justify-content: space-between;
    margin-top: 8px;
    color: #aaa2ac;
    font-size: 7px;
}

.trend-note {
    margin-top: 18px;
    padding: 14px;
    border-radius: 17px;
    background: #ece1f6;
    color: #79559b;
    font-size: 14px;
}

.trend-note small {
    display: block;
    margin: 4px 0 0 15px;
    color: #8d8292;
    font-size: 12px;
}

/* 瞬间图片 */
.moment-image {
    position: relative;
    height: 315px;
    border-radius: 27px;
    overflow: hidden;
    background: radial-gradient(circle, #fff, #dbc7ed);
}

.moment-image img {
    width: 100%;
    height: 100%;
    object-fit: contain;
}

.moment-image span {
    position: absolute;
    left: 12px;
    bottom: 12px;
    padding: 8px 10px;
    border-radius: 10px;
    background: rgba(255, 255, 255, .8);
    font-size: 7px;
}

.phone-view[data-view="moments"] h4 {
    text-align: left;
    font-size: 21px;
}

.phone-view[data-view="moments"] .view-copy {
    text-align: left;
}

/* 聊天界面 */
.chat-parent {
    margin: 30px 0 12px 40px;
    padding: 13px;
    border-radius: 16px 16px 4px 16px;
    background: var(--ink);
    color: #fff;
    font-size: 14px;
    line-height: 1.5;
}

.chat-ai {
    display: flex;
    gap: 8px;
    padding: 14px;
    border-radius: 4px 16px 16px;
    background: #ecdef7;
}

.chat-ai i {
    color: var(--purple-strong);
    font-style: normal;
}

.chat-ai p {
    margin: 0;
    font-size: 14px;
    line-height: 1.65;
}

/* 边界提示 */
.boundary {
    margin-top: 5px;
    padding: 5px 15px;
    border-radius: 17px;
}

.boundary b,
.boundary span {
    display: block;
}

.boundary b {
    font-size: 9px;
}

.boundary span {
    margin-top: 7px;
    color: #7d7365;
    font-size: 10px;
    line-height: 1.5;
}

/* 底部 Tab 栏 */
.app-tabs {
    position: absolute;
    left: 20px;
    right: 20px;
    bottom: 18px;
    display: flex;
    justify-content: space-around;
}

.app-tabs i {
    width: 25px;
    height: 4px;
    border-radius: 5px;
    background: #dedede;
}

.app-tabs i.active {
    background: var(--purple-strong);
}

/* ============================================================
   功能步骤（Feature Steps）
   ============================================================ */
.feature-steps {
    position: relative;
    z-index: 3;
    padding-bottom: 160px;
}

.feature-step {
    min-height: 72vh;
    padding: 70px 12px 80px;
    display: flex;
    flex-direction: column;
    justify-content: center;
    opacity: .35;
    transition: opacity .45s;
}

.feature-step.active {
    opacity: 1;
}

.feature-step > span {
    color: var(--purple-strong);
    font-size: 10px;
    font-weight: 900;
    letter-spacing: .14em;
}

.feature-step h3 {
    margin: 27px 0 18px;
    font-size: clamp(36px, 4vw, 61px);
    line-height: 1.06;
    letter-spacing: -.055em;
}

.feature-step p {
    max-width: 510px;
    margin: 0;
    color: var(--muted);
    font-size: 17px;
    line-height: 1.8;
}

.feature-step button {
    width: max-content;
    margin-top: 28px;
    padding: 0;
    background: none;
    font-size: 12px;
    font-weight: 850;
}

.feature-step button i {
    display: inline-grid;
    place-items: center;
    width: 30px;
    height: 30px;
    margin-left: 10px;
    border-radius: 50%;
    background: var(--ink);
    color: #fff;
    font-style: normal;
}

/* ============================================================
   下载区域（Download）
   ============================================================ */
.download-section {
    min-height: 760px;
    display: grid;
    grid-template-columns: 1fr 1fr;
    background: #ebe0f4;
}

.download-visual {
    position: relative;
    display: grid;
    place-items: center;
    overflow: hidden;
}

.download-visual img {
    position: relative;
    width: 68%;
    filter: drop-shadow(0 35px 45px rgba(70, 55, 74, .18));
}

.download-copy {
    padding: 100px 9vw 80px 5vw;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.download-copy > p:first-child {
    font-size: 11px;
    font-weight: 900;
    letter-spacing: .15em;
}

.download-copy h2 {
    margin: 25px 0;
    font-size: clamp(50px, 6vw, 91px);
    line-height: .98;
    letter-spacing: -.065em;
}

.download-copy > p:nth-of-type(2) {
    max-width: 520px;
    color: var(--muted);
    font-size: 17px;
    line-height: 1.75;
}

.download-copy .app-button {
    width: 220px;
    margin-top: 22px;
}

.download-copy > small {
    max-width: 520px;
    margin-top: 24px;
    color: #7e7583;
    line-height: 1.7;
}

/* ============================================================
   页脚（Footer）
   ============================================================ */
.site-footer {
    padding: 90px 0 28px;
    background: var(--ink);
    color: #fff;
}

.footer-top {
    position: relative;
    display: grid;
    grid-template-columns: 1.3fr .55fr .8fr auto;
    gap: 70px;
    align-items: start;
}

.footer-brand h2 {
    margin: 20px 0 0;
    font-size: clamp(32px, 3.5vw, 53px);
    line-height: 1.06;
    letter-spacing: -.05em;
}

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

.footer-links > p,
.footer-social > p {
    margin: 4px 0 16px;
    color: #8f8792;
    font-size: 9px;
    font-weight: 900;
    letter-spacing: .15em;
}

.footer-links a {
    width: max-content;
    color: #cbc4cd;
    font-size: 13px;
}

.qr-wrap {
    display: flex;
    align-items: center;
    gap: 14px;
}

.qr-wrap img {
    width: 120px;
    height: 120px;
    border-radius: 17px;
    background: #fff;
}

.qr-wrap span {
    color: #aaa2ad;
    font-size: 10px;
    line-height: 1.6;
}

.back-to-top {
    width: 100px;
    height: 100px;
    border: 1px solid rgba(255, 255, 255, .23);
    border-radius: 50%;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 4px;
    background: transparent;
    color: #fff;
    transition: transform .35s var(--ease), background .35s;
}

.back-to-top:hover {
    transform: translateY(-8px);
    background: rgba(255, 255, 255, .08);
}

.back-to-top span {
    font-size: 26px;
}

.back-to-top b {
    font-size: 12px;
}

.footer-bottom {
    margin-top: 70px;
    padding-top: 23px;
    border-top: 1px solid rgba(51, 47, 54, 0.8);
    display: flex;
    justify-content: space-between;
    color: #514d53;
    font-size: 11px;
}

.footer-bottom a {
    color: inherit;
    text-decoration: none;
}

/* ============================================================
   滚动揭示动画
   ============================================================ */
.reveal {
    opacity: 0;
    transform: translateY(38px);
    transition: opacity .9s var(--ease), transform .9s var(--ease);
}

.reveal.visible {
    opacity: 1;
    transform: none;
}

/* ============================================================
   关键帧动画
   ============================================================ */
@keyframes productFloat {
    0%, 100% { transform: translateY(0); }
    50% { transform: translateY(-12px); }
}

/* ============================================================
   响应式适配
   ============================================================ */

/* --- 平板端 (<= 1020px) --- */
@media (max-width: 1020px) {
    .site-header {
        grid-template-columns: 1fr auto;
    }

    .desktop-nav {
        display: none;
    }

    .menu-toggle {
        justify-self: end;
        width: 43px;
        height: 43px;
        border: 0;
        border-radius: 50%;
        display: grid;
        place-content: center;
        gap: 5px;
        background: var(--ink);
    }

    .menu-toggle span {
        display: block;
        width: 16px;
        height: 1px;
        background: #fff;
    }

    .mobile-nav {
        position: absolute;
        top: 78px;
        left: 0;
        right: 0;
        padding: 25px;
        border-radius: 28px;
        display: flex;
        flex-direction: column;
        gap: 18px;
        background: var(--paper);
        box-shadow: 0 22px 50px rgba(40, 36, 45, .14);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-8px);
        transition: .3s;
    }

    .mobile-nav.open {
        opacity: 1;
        visibility: visible;
        transform: none;
    }

    .mobile-nav a {
        text-decoration: none;
        font-weight: 800;
    }

    .hero {
        grid-template-columns: 1fr;
        padding-top: 150px;
    }

    .hero-visual {
        min-height: 590px;
    }

    .film-screen {
        aspect-ratio: 16 / 10;
    }

    .promise-inner {
        grid-template-columns: 1fr;
        gap: 70px;
    }

    .promise-sticky {
        position: static;
    }

    .system-heading {
        grid-template-columns: 1fr;
    }

    .app-story-layout {
        grid-template-columns: .9fr 1.1fr;
        gap: 45px;
    }

    .iphone {
        width: 300px;
        height: 620px;
        border-radius: 54px;
    }

    .phone-screen {
        border-radius: 45px;
    }

    .phone-stage {
        min-height: 680px;
    }

    .footer-top {
        grid-template-columns: 1fr 1fr;
        gap: 55px;
    }

    .back-to-top {
        position: absolute;
        right: 0;
        top: 0;
    }
}

/* --- 移动端 (<= 700px) --- */
@media (max-width: 700px) {
    :root {
        --shell: calc(100% - 30px - var(--safe-left) - var(--safe-right));
    }

    .site-header {
        top: 10px;
        height: 60px;
    }

    .brand b {
        display: none;
    }

    .hero {
        gap: 10px;
    }

    .hero h1 {
        font-size: 44px;
    }

    .hero-lead {
        font-size: 15px;
    }

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

    .text-button {
        justify-content: space-between;
    }

    .hero-visual {
        min-height: 480px;
    }

    .floating-label {
        font-size: 10px;
    }

    .film-section,
    .promise {
        padding-top: 85px;
        padding-bottom: 80px;
    }

    .film-intro {
        display: block;
    }

    .film-intro > p:last-child {
        margin-top: 18px;
    }

    .film-screen {
        aspect-ratio: 16 / 9;
        border-radius: 28px;
    }

    .film-screen > video {
        object-fit: contain;
    }

    .principle,
    .system {
        padding-top: 90px;
        padding-bottom: 90px;
    }

    .editorial-heading h2,
    .system-heading h2,
    .app-story-title h2 {
        margin-bottom: 45px;
        font-size: 39px;
    }

    .principle-item {
        grid-template-columns: 38px 1fr;
    }

    .principle-item > i {
        display: none;
    }

    .promise-card {
        min-height: 240px;
    }

    .system-canvas {
        min-height: 780px;
        border-radius: 30px;
    }

    .system-rings i:nth-child(1) { width: 460px; height: 460px; }
    .system-rings i:nth-child(2) { width: 330px; height: 330px; }
    .system-rings i:nth-child(3) { width: 230px; height: 230px; }

    .system-core {
        width: 180px;
        height: 180px;
    }

    .system-node {
        width: 220px;
        padding: 18px;
    }

    .node-one { left: 4%; top: 3%; }
    .node-two { right: 3%; top: auto; bottom: 26%; }
    .node-three { left: 5%; right: auto; bottom: 2%; }

    .data-loop {
        gap: 6px;
        flex-wrap: wrap;
    }

    .data-loop span {
        padding: 8px 11px;
        font-size: 10px;
    }

    .app-story {
        padding-top: 90px;
    }

    .app-story-title > p:last-child {
        margin-top: -25px;
    }

    .app-story-layout {
        display: block;
    }

    .phone-stage {
        position: relative;
        top: 0;
        min-height: 680px;
        margin-bottom: 40px;
        overflow: hidden;
        border-radius: 36px;
    }

    .phone-aura {
        width: clamp(260px, 82vw, 360px);
        max-width: calc(100% - 20px);
    }

    .iphone {
        width: 300px;
        height: 620px;
    }

    .feature-steps {
        position: relative;
        z-index: 3;
        background: var(--cream);
        padding-bottom: 80px;
    }

    .feature-step {
        min-height: auto;
        padding: 48px 4px;
        opacity: 1;
    }

    .feature-step h3 {
        font-size: 38px;
    }

    .feature-step p {
        font-size: 15px;
    }

    .download-section {
        grid-template-columns: 1fr;
    }

    .download-visual {
        min-height: 450px;
    }

    .download-copy {
        padding: 70px 9vw;
    }

    .footer-top {
        grid-template-columns: 1fr;
        gap: 45px;
    }

    .footer-brand h2 {
        margin-top: 35px;
    }

    .back-to-top {
        width: 82px;
        height: 82px;
    }

    .footer-bottom {
        display: block;
    }

    .footer-bottom p {
        margin: 8px 0;
    }

}

/* --- 减少动画偏好 --- */
@media (prefers-reduced-motion: reduce) {
    html {
        scroll-behavior: auto;
    }

    *,
    *::before,
    *::after {
        animation-duration: .01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: .01ms !important;
    }

    .reveal {
        opacity: 1;
        transform: none;
    }
}