/* ==========================================================================
   和助理 官网首页样式（专业版 v0.4.0）
   设计语言：品牌蓝 + 轻盈投影 + 大圆角卡片 + 克制的微动效
   ========================================================================== */

:root {
    /* 品牌色 */
    --primary: #1a8cff;
    --primary-strong: #0b6fe0;
    --primary-deep: #0856b8;
    --primary-soft: rgba(26, 140, 255, .08);
    --primary-line: rgba(26, 140, 255, .22);
    --gradient-primary: linear-gradient(135deg, #35a3ff 0%, #1179ef 55%, #0a5fc9 100%);

    /* 文字 */
    --ink: #1b2735;
    --ink-2: #3d4c60;
    --muted: #74839a;
    --muted-2: #98a5b8;

    /* 背景 / 分割线 */
    --bg: #ffffff;
    --bg-soft: #f5f9fe;
    --bg-band: linear-gradient(180deg, #f3f8ff 0%, #eef4fc 100%);
    --line: #e8eef6;

    /* 形态 */
    --nav-h: 68px;
    --radius-sm: 12px;
    --radius: 20px;
    --radius-lg: 28px;

    /* 投影：三级 */
    --shadow-xs: 0 2px 10px rgba(20, 60, 120, .05);
    --shadow-sm: 0 10px 30px rgba(20, 60, 120, .08);
    --shadow-md: 0 18px 46px rgba(18, 58, 112, .12);
    --shadow-lg: 0 30px 70px rgba(14, 52, 104, .18);
    --shadow-primary: 0 14px 30px rgba(11, 111, 224, .34);

    --ease: cubic-bezier(.22, .61, .36, 1);
}

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

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

body {
    font-family: "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Arial, sans-serif;
    font-size: 16px;
    line-height: 1.65;
    color: var(--ink);
    background: var(--bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

::selection {
    background: rgba(26, 140, 255, .18);
    color: var(--primary-deep);
}

img {
    display: block;
    max-width: 100%;
    border: 0;
}

a {
    color: inherit;
    text-decoration: none;
    -webkit-tap-highlight-color: transparent;
}

ul {
    list-style: none;
}

button {
    font: inherit;
    border: 0;
    background: none;
    cursor: pointer;
    -webkit-tap-highlight-color: transparent;
}

a:focus-visible,
button:focus-visible {
    outline: 3px solid rgba(26, 140, 255, .35);
    outline-offset: 2px;
}

.container {
    width: 100%;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 24px;
}

/* 屏幕阅读器专用 */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ---------- 顶部导航 ---------- */
.site-nav {
    position: fixed;
    top: 0;
    left: 0;
    right: 0;
    z-index: 1000;
    height: var(--nav-h);
    background: rgba(255, 255, 255, .82);
    -webkit-backdrop-filter: blur(16px) saturate(180%);
    backdrop-filter: blur(16px) saturate(180%);
    border-bottom: 1px solid transparent;
    transition: background-color .3s ease, border-color .3s ease, box-shadow .3s ease;
}

.site-nav.scrolled {
    background: rgba(255, 255, 255, .94);
    border-bottom-color: rgba(18, 58, 112, .08);
    box-shadow: 0 8px 30px rgba(18, 58, 112, .08);
}

.nav-inner {
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
}

.nav-brand {
    display: flex;
    align-items: center;
    gap: 14px;
    min-width: 0;
}

.brand {
    display: flex;
    align-items: center;
    gap: 10px;
    font-size: 20px;
    font-weight: 700;
    letter-spacing: .01em;
    color: var(--ink);
    white-space: nowrap;
}

.brand img {
    height: 38px;
    width: auto;
}

.nav-links {
    display: flex;
    align-items: center;
    gap: 4px;
}

.nav-links a {
    position: relative;
    display: block;
    padding: 9px 16px;
    border-radius: 10px;
    font-size: 15px;
    font-weight: 500;
    color: var(--ink-2);
    transition: color .2s var(--ease), background-color .2s var(--ease);
}

.nav-links a:hover,
.nav-links a:focus {
    color: var(--primary);
    background: var(--primary-soft);
}

.nav-links a.active {
    color: var(--primary);
    font-weight: 600;
}

.nav-links a.active::after {
    content: "";
    position: absolute;
    left: 50%;
    bottom: 1px;
    width: 18px;
    height: 3px;
    border-radius: 3px;
    background: var(--gradient-primary);
    transform: translateX(-50%);
}

.nav-cta {
    margin-left: 10px;
    padding: 10px 26px !important;
    border-radius: 999px !important;
    background: var(--gradient-primary) !important;
    color: #fff !important;
    font-weight: 600;
    box-shadow: var(--shadow-primary);
    transition: transform .25s var(--ease), box-shadow .25s var(--ease), background-color .25s !important;
}

.nav-cta::after {
    display: none;
}

.nav-cta:hover,
.nav-cta:focus {
    color: #fff !important;
    background: var(--gradient-primary) !important;
    transform: translateY(-2px);
    box-shadow: 0 18px 36px rgba(11, 111, 224, .42);
}

/* 移动端顶部常驻的下载入口 */
.nav-dl {
    display: none;
    padding: 8px 16px;
    border-radius: 999px;
    font-size: 14px;
    font-weight: 600;
    color: var(--primary);
    background: var(--primary-soft);
    border: 1px solid var(--primary-line);
    white-space: nowrap;
    transition: background-color .2s var(--ease);
}

.nav-dl:hover {
    background: rgba(26, 140, 255, .14);
}

.nav-toggle {
    display: none;
    flex-direction: column;
    justify-content: center;
    gap: 5px;
    width: 42px;
    height: 42px;
    padding: 10px;
    border-radius: 10px;
}

.nav-toggle span {
    display: block;
    height: 2px;
    width: 100%;
    border-radius: 2px;
    background: var(--ink);
    transition: transform .25s var(--ease), opacity .25s var(--ease);
}

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

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

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

/* ---------- 首屏轮播 ---------- */
.hero {
    position: relative;
    margin-top: var(--nav-h);
    overflow: hidden;
    background: #0e1c2c;
}

.hero-track {
    display: grid;
}

.slide {
    max-width: 1080px;
    margin:0 auto;
    grid-area: 1 / 1;
    opacity: 0;
    transition: opacity .9s var(--ease);
    will-change: opacity;
}

.slide.active {
    opacity: 1;
    z-index: 1;
}

.slide img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    aspect-ratio: 1903 / 800;
    transform: scale(1.06);
    transition: transform 7s linear;
}

.slide.active img {
    transform: scale(1);
}

.hero-shade {
    position: absolute;
    inset: 0;
    z-index: 2;
    background:
        linear-gradient(90deg, rgba(7, 18, 34, .34) 0%, rgba(7, 18, 34, 0) 38%),
        linear-gradient(180deg, rgba(7, 18, 34, .26) 0%, rgba(7, 18, 34, 0) 26%, rgba(7, 18, 34, 0) 52%, rgba(7, 18, 34, .62) 100%);
    pointer-events: none;
}

/* 左右切换箭头 */
.hero-arrow {
    position: absolute;
    top: 50%;
    z-index: 5;
    width: 50px;
    height: 50px;
    margin-top: -25px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: #fff;
    background: rgba(255, 255, 255, .14);
    border: 1px solid rgba(255, 255, 255, .28);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
    opacity: 0;
    transform: translateY(0);
    transition: background-color .25s var(--ease), opacity .25s var(--ease);
}

.hero:hover .hero-arrow,
.hero-arrow:focus-visible {
    opacity: 1;
}

.hero-arrow:hover {
    background: rgba(255, 255, 255, .26);
}

.hero-arrow.prev {
    left: 26px;
}

.hero-arrow.next {
    right: 26px;
}

.hero-arrow svg {
    width: 22px;
    height: 22px;
}

/* 行动按钮组 */
.hero-actions {
    position: absolute;
    left: 50%;
    bottom: 52px;
    z-index: 5;
    transform: translateX(-50%);
    display: flex;
    align-items: center;
    gap: 14px;
}

.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 38px;
    border-radius: 999px;
    font-size: 13px;
    font-weight: 600;
    letter-spacing: .02em;
    transition: transform .25s var(--ease), box-shadow .25s var(--ease), background-color .25s var(--ease), border-color .25s var(--ease);
}

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

.btn-primary:hover,
.btn-primary:focus {
    color: #fff;
    transform: translateY(-3px);
    box-shadow: 0 20px 40px rgba(11, 111, 224, .5);
}

.btn-ghost {
    color: #fff;
    background: rgba(255, 255, 255, .12);
    border: 1px solid rgba(255, 255, 255, .45);
    -webkit-backdrop-filter: blur(8px);
    backdrop-filter: blur(8px);
}

.btn-ghost:hover,
.btn-ghost:focus {
    color: #fff;
    background: rgba(255, 255, 255, .22);
    transform: translateY(-3px);
}

.hero-dots {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 18px;
    z-index: 5;
    display: flex;
    justify-content: center;
    gap: 8px;
}

.dot {
    width: 9px;
    height: 9px;
    padding: 0;
    border-radius: 5px;
    background: rgba(255, 255, 255, .45);
    transition: width .3s var(--ease), background-color .3s var(--ease);
}

.dot.active {
    width: 24px;
    background: #fff;
}

/* 底部播放进度条 */
.hero-progress {
    position: absolute;
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 6;
    height: 3px;
    background: rgba(255, 255, 255, .16);
}

.hero-progress .bar {
    width: 0;
    height: 100%;
    background: linear-gradient(90deg, #6fc0ff, #fff);
    border-radius: 0 3px 3px 0;
}

.hero-progress.running .bar {
    animation: heroBar 4.5s linear forwards;
}

@keyframes heroBar {
    from { width: 0; }
    to { width: 100%; }
}

/* ---------- 通用区块头 ---------- */
.section-head {
    text-align: center;
    padding: 84px 24px 10px;
}

.eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 18px;
    border-radius: 999px;
    font-size: 12.5px;
    font-weight: 700;
    letter-spacing: .22em;
    text-indent: .22em;
    color: var(--primary);
    background: var(--primary-soft);
    border: 1px solid var(--primary-line);
}

.section-head h2 {
    margin-top: 20px;
    font-size: 34px;
    font-weight: 700;
    letter-spacing: .01em;
    color: var(--ink);
}

.section-head p {
    max-width: 620px;
    margin: 14px auto 0;
    font-size: 16px;
    color: var(--muted);
}

/* ---------- 功能展示 ---------- */
.feature {
    padding: 30px 0;
}

.feature:nth-of-type(even) {
    padding: 54px 0;
    background: var(--bg-band);
}

.feature-card {
    max-width: 1080px;
    margin: 0 auto;
    background: #fff;
    border: 1px solid rgba(20, 60, 120, .07);
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-sm);
    transition: transform .45s var(--ease), box-shadow .45s var(--ease), border-color .45s var(--ease);
}

.feature-card:hover {
    transform: translateY(-6px);
    border-color: rgba(26, 140, 255, .18);
    box-shadow: var(--shadow-lg);
}

.feature-media {
    overflow: hidden;
}

.feature-media img {
    width: 100%;
    transition: transform .8s var(--ease);
}

.feature-card:hover .feature-media img {
    transform: scale(1.015);
}

/* 手机截图在图片中的水平位置：左 / 右，用于移动端裁剪 */
.pos-left {
    object-position: 27% 50%;
}

.pos-right {
    object-position: 73% 50%;
}

.feature-caption {
    display: none;
    padding: 22px 26px 28px;
}

.feature-caption h3 {
    position: relative;
    padding-left: 14px;
    font-size: 19px;
    font-weight: 700;
    color: var(--ink);
}

.feature-caption h3::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 5px;
    height: 20px;
    border-radius: 3px;
    transform: translateY(-50%);
    background: var(--gradient-primary);
}

.feature-caption p {
    margin-top: 8px;
    font-size: 14.5px;
    line-height: 1.75;
    color: var(--muted);
}

/* ---------- 宣传横幅 ---------- */
.promo {
    padding: 64px 0;
}

.promo-card {
    max-width: 1080px;
    margin: 0 auto;
    border-radius: var(--radius-lg);
    overflow: hidden;
    box-shadow: var(--shadow-md);
    transition: transform .45s var(--ease), box-shadow .45s var(--ease);
}

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

.promo-card img {
    width: 100%;
}

/* ---------- 下载区 ---------- */
.download {
    padding: 30px 0 96px;
}

.download-card {
    position: relative;
    max-width: 1080px;
    margin: 0 auto;
    padding: 64px 64px;
    border-radius: var(--radius-lg);
    background: var(--gradient-primary);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 56px;
    overflow: hidden;
    box-shadow: 0 28px 70px rgba(10, 90, 190, .38);
}

/* 氛围光斑 */
.download-card::before,
.download-card::after {
    content: "";
    position: absolute;
    border-radius: 50%;
    pointer-events: none;
}

.download-card::before {
    width: 380px;
    height: 380px;
    top: -170px;
    right: -90px;
    background: radial-gradient(circle, rgba(255, 255, 255, .18), rgba(255, 255, 255, 0) 68%);
}

.download-card::after {
    width: 260px;
    height: 260px;
    left: -110px;
    bottom: -130px;
    background: radial-gradient(circle, rgba(255, 255, 255, .12), rgba(255, 255, 255, 0) 68%);
}

.download-info {
    position: relative;
    z-index: 1;
    flex: 1 1 auto;
}

.download-eyebrow {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 6px 16px;
    border-radius: 999px;
    font-size: 12.5px;
    font-weight: 700;
    letter-spacing: .18em;
    text-indent: .18em;
    color: #fff;
    background: rgba(255, 255, 255, .14);
    border: 1px solid rgba(255, 255, 255, .28);
}

.download-card h2 {
    margin-top: 20px;
    font-size: 33px;
    font-weight: 700;
    letter-spacing: .01em;
}

.download-info > p {
    margin-top: 12px;
    font-size: 16.5px;
    color: rgba(255, 255, 255, .86);
}

.platform-chips {
    display: flex;
    flex-wrap: wrap;
    gap: 10px;
    margin-top: 24px;
}

.platform-chips .chip {
    display: inline-flex;
    align-items: center;
    gap: 7px;
    padding: 8px 16px;
    border-radius: 999px;
    font-size: 10px;
    font-weight: 100;
    color: #fff;
    background: rgba(255, 255, 255, .12);
    border: 1px solid rgba(255, 255, 255, .24);
    -webkit-backdrop-filter: blur(6px);
    backdrop-filter: blur(6px);
}

.platform-chips .chip svg {
    width: 15px;
    height: 15px;
}

.store-btns {
    display: flex;
    flex-wrap: wrap;
    gap: 16px;
    margin-top: 32px;
}

.store-btns a {
    display: inline-flex;
    align-items: center;
    background: #fff;
    border-radius: 14px;
    padding: 13px 22px;
    box-shadow: 0 12px 26px rgba(5, 40, 90, .22);
    transition: transform .25s var(--ease), box-shadow .25s var(--ease);
}

.store-btns img {
    height: 40px;
    width: auto;
}

.store-btns a:hover,
.store-btns a:focus {
    transform: translateY(-4px);
    box-shadow: 0 18px 34px rgba(5, 40, 90, .3);
}

/* 扫码下载 */
.download-qr {
    position: relative;
    z-index: 1;
    flex: 0 0 216px;
    width: 216px;
    background: #fff;
    border-radius: var(--radius);
    padding: 14px 14px 12px;
    text-align: center;
    box-shadow: 0 18px 44px rgba(5, 40, 90, .28);
}

.download-qr .qr-img {
    width: 100%;
    border-radius: 12px;
}

.download-qr .qr-caption {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 6px;
    margin-top: 10px;
    font-size: 12.5px;
    font-weight: 500;
    color: var(--muted);
}

.download-qr .qr-caption img {
    height: 15px;
    width: auto;
}

/* ---------- 页脚 ---------- */
.site-footer {
    background: #0d1928;
    color: #93a3b5;
}

.footer-main {
    display: flex;
    flex-wrap: wrap;
    gap: 56px;
    padding: 60px 0 46px;
}

.footer-brand {
    flex: 1 1 280px;
}

.footer-brand strong {
    display: block;
    font-size: 21px;
    letter-spacing: .02em;
    color: #fff;
}

.footer-brand p {
    margin-top: 12px;
    font-size: 14px;
    line-height: 1.9;
    color: #8294a8;
}

.footer-col {
    min-width: 168px;
}

.footer-col h4 {
    position: relative;
    margin-bottom: 18px;
    padding-left: 12px;
    font-size: 15px;
    font-weight: 600;
    color: #fff;
}

.footer-col h4::before {
    content: "";
    position: absolute;
    left: 0;
    top: 50%;
    width: 4px;
    height: 15px;
    border-radius: 2px;
    transform: translateY(-50%);
    background: var(--gradient-primary);
}

.footer-col a {
    display: block;
    padding: 6px 0;
    font-size: 14px;
    color: #93a3b5;
    transition: color .2s var(--ease), transform .2s var(--ease);
}

.footer-col a:hover,
.footer-col a:focus {
    color: #fff;
    transform: translateX(3px);
}

.footer-bottom {
    border-top: 1px solid rgba(255, 255, 255, .08);
    padding: 22px 0;
    text-align: center;
    font-size: 13px;
    color: #6b7c90;
}

.footer-bottom a {
    color: #8fa2b8;
    transition: color .2s;
}

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

/* ---------- 返回顶部 ---------- */
.back-top {
    position: fixed;
    right: 28px;
    bottom: 28px;
    z-index: 900;
    width: 46px;
    height: 46px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: var(--primary-strong);
    background: #fff;
    box-shadow: var(--shadow-md);
    opacity: 0;
    visibility: hidden;
    transform: translateY(14px);
    transition: opacity .3s var(--ease), transform .3s var(--ease), color .2s, background-color .2s, visibility .3s;
}

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

.back-top:hover {
    color: #fff;
    background: var(--gradient-primary);
}

.back-top svg {
    width: 20px;
    height: 20px;
}

/* ---------- 滚动进入动效 ---------- */
[data-reveal] {
    opacity: 0;
    transform: translateY(30px);
    transition: opacity .8s var(--ease), transform .8s var(--ease);
    transition-delay: var(--d, 0s);
}

[data-reveal].is-visible {
    opacity: 1;
    transform: translateY(0);
}

/* ---------- 平板 / 手机适配 ---------- */
@media (max-width: 900px) {
    .nav-toggle {
        display: flex;
    }

    .nav-dl {
        display: inline-flex;
    }

    .nav-links {
        position: fixed;
        top: var(--nav-h);
        left: 0;
        right: 0;
        z-index: 999;
        flex-direction: column;
        align-items: stretch;
        gap: 0;
        padding: 10px 20px 22px;
        background: rgba(255, 255, 255, .98);
        -webkit-backdrop-filter: blur(16px);
        backdrop-filter: blur(16px);
        box-shadow: 0 24px 40px rgba(23, 58, 110, .14);
        opacity: 0;
        visibility: hidden;
        transform: translateY(-12px);
        transition: opacity .25s var(--ease), transform .25s var(--ease), visibility .25s;
    }

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

    .nav-links a {
        padding: 15px 10px;
        font-size: 16px;
        border-bottom: 1px solid var(--line);
        border-radius: 0;
    }

    .nav-links a.active::after {
        left: auto;
        right: 10px;
        bottom: 50%;
        margin-bottom: -9px;
        transform: none;
    }

    .nav-cta {
        margin: 16px 0 0;
        text-align: center;
        border-bottom: 0 !important;
    }

    .nav-cta::after {
        display: none;
    }

    .hero-arrow {
        display: none;
    }
}

@media (max-width: 768px) {
    .container {
        padding: 0 16px;
    }

    .hero-actions {
        bottom: 34px;
        gap: 10px;
    }

    .hero-dots {
        bottom: 10px;
    }

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

    .section-head {
        padding: 56px 20px 4px;
    }

    .section-head h2 {
        font-size: 25px;
        margin-top: 16px;
    }

    .section-head p {
        font-size: 14.5px;
    }

    .feature {
        padding: 14px 16px;
    }

    .feature:nth-of-type(even) {
        padding: 26px 16px;
    }

    /* 移动端：图片裁剪聚焦手机区域，标题用文字呈现 */
    .feature-media {
        overflow: hidden;
        background: #f4f7fb;
    }

    .feature-media img {
        width: 100%;
/*        height: 238px;*/
        object-fit: cover;
    }

    .feature-caption {
        display: block;
    }

    .feature-card,
    .promo-card,
    .download-card {
        border-radius: var(--radius);
    }

    .promo {
        padding: 28px 16px;
    }

    .download {
        padding: 14px 16px 60px;
    }

    .download-card {
        flex-direction: column;
        padding: 42px 24px 40px;
        gap: 34px;
        text-align: center;
    }

    .download-card h2 {
        font-size: 13px;
    }

    .download-info > p {
        font-size: 11px;
    }

    .platform-chips {
        justify-content: center;
    }

    .download-qr {
        flex: 0 0 auto;
        width: 100%;
        max-width: 180px;
    }

    .store-btns {
        justify-content: center;
        gap: 14px;
        margin-top: 28px;
    }

    .store-btns img {
        height: 40px;
    }

    .footer-main {
        flex-direction: column;
        gap: 30px;
        padding: 44px 0 30px;
    }

    .back-top {
        right: 18px;
        bottom: 18px;
        width: 42px;
        height: 42px;
    }
}

@media (max-width: 380px) {
    .nav-dl {
        padding: 7px 12px;
        font-size: 13px;
    }

    .brand img {
        height: 34px;
    }

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

    .store-btns {
        flex-direction: column;
        align-items: center;
    }

    .store-btns a {
        width: 220px;
        justify-content: center;
    }
}

@media (prefers-reduced-motion: reduce) {
    *,
    *::before,
    *::after {
        transition: none !important;
        animation: none !important;
    }

    html {
        scroll-behavior: auto;
    }

    [data-reveal] {
        opacity: 1 !important;
        transform: none !important;
    }

    .slide img {
        transform: none !important;
    }
}