/* ==========================================================================
   和助理 客户端下载页样式（专业版 v0.4.0）
   ========================================================================== */

: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;

    /* 背景 / 分割线 */
    --line: #e8eef6;
    --bg-soft: #f4f8fe;

    /* 形态 */
    --nav-h: 68px;
    --radius-sm: 12px;
    --radius: 20px;
    --radius-lg: 26px;

    /* 投影 */
    --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);
}

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

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

body {
    position: relative;
    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: linear-gradient(180deg, #edf5ff 0%, #f5f9fe 34%, #f4f8fd 100%);
    background-attachment: fixed;
    min-height: 100vh;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    text-rendering: optimizeLegibility;
}

/* 氛围光斑 */
body::before,
body::after {
    content: "";
    position: fixed;
    z-index: 0;
    border-radius: 50%;
    pointer-events: none;
}

body::before {
    width: 520px;
    height: 520px;
    top: -180px;
    left: -160px;
    background: radial-gradient(circle, rgba(92, 173, 255, .28), rgba(92, 173, 255, 0) 68%);
}

body::after {
    width: 460px;
    height: 460px;
    right: -150px;
    bottom: -160px;
    background: radial-gradient(circle, rgba(52, 140, 255, .2), rgba(52, 140, 255, 0) 68%);
}

::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;
}

button {
    font: inherit;
    border: 0;
    background: none;
    cursor: pointer;
    color: inherit;
    -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;
}

/* ---------- 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);
}

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

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

.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);
}

/* ---------- 下载主体 ---------- */
.download-wrap {
    position: relative;
    z-index: 1;
    min-height: 100vh;
    padding: calc(var(--nav-h) + 72px) 24px 88px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.dl-card {
    position: relative;
    width: 100%;
    max-width: 480px;
    padding: 44px 42px 38px;
    background: rgba(255, 255, 255, .92);
    border: 1px solid rgba(20, 60, 120, .07);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    text-align: center;
    -webkit-backdrop-filter: blur(10px);
    backdrop-filter: blur(10px);
    animation: cardIn .7s var(--ease) both;
}

@keyframes cardIn {
    from { opacity: 0; transform: translateY(26px); }
    to { opacity: 1; transform: translateY(0); }
}

/* 品牌 */
.dl-brand {
    display: flex;
    justify-content: center;
}

.dl-brand img {
    height: 40px;
    width: auto;
}

.dl-title {
    margin-top: 18px;
    font-size: 26px;
    font-weight: 700;
    letter-spacing: .01em;
}

.dl-intro {
    margin-top: 8px;
    font-size: 14.5px;
    color: var(--muted);
}

/* 二维码 */
.dl-qr {
    position: relative;
    width: 200px;
    margin: 28px auto 0;
    padding: 12px;
    border-radius: 20px;
    background: #fff;
    border: 1px solid var(--line);
    box-shadow: var(--shadow-sm);
}

.dl-qr::before {
    content: "";
    position: absolute;
    inset: 7px;
    border-radius: 14px;
    border: 1.5px solid rgba(26, 140, 255, .25);
    opacity: 0;
    transition: opacity .3s var(--ease);
    pointer-events: none;
}

.dl-qr:hover::before {
    opacity: 1;
}

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

.dl-qr-tip {
    margin-top: 14px;
    font-size: 13px;
    color: var(--muted);
}

/* 分割线 */
.dl-divider {
    display: flex;
    align-items: center;
    gap: 14px;
    margin: 28px 0 20px;
    color: var(--muted);
    font-size: 12.5px;
    letter-spacing: .04em;
}

.dl-divider::before,
.dl-divider::after {
    content: "";
    flex: 1;
    height: 1px;
    background: var(--line);
}

/* 平台下载按钮 */
.dl-btns {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.dl-btn {
    display: flex;
    align-items: center;
    gap: 12px;
    width: 100%;
    padding: 14px 20px;
    border-radius: 14px;
    font-size: 15.5px;
    font-weight: 600;
    transition: transform .25s var(--ease), box-shadow .25s var(--ease), background-color .25s var(--ease), border-color .25s var(--ease), color .2s;
}

.dl-btn .ic {
    flex: 0 0 auto;
    width: 22px;
    height: 22px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.dl-btn .ic svg {
    width: 22px;
    height: 22px;
}

.dl-btn .dl-btn-label {
    flex: 1 1 auto;
    text-align: center;
}

.dl-btn .arrow {
    flex: 0 0 auto;
    width: 16px;
    height: 16px;
    opacity: .75;
    transition: transform .25s var(--ease), opacity .25s var(--ease);
}

.dl-btn .arrow svg {
    width: 16px;
    height: 16px;
}

.dl-btn:hover .arrow {
    transform: translateX(3px);
    opacity: 1;
}

/* 主按钮：Android（直接下载） */
.dl-btn.btn-primary {
    background: var(--gradient-primary);
    color: #fff;
    box-shadow: var(--shadow-primary);
}

.dl-btn.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 18px 38px rgba(11, 111, 224, .42);
}

/* 次按钮：iOS / HarmonyOS */
.dl-btn.btn-ghost {
    background: #f2f7fe;
    color: var(--primary-strong);
    border: 1px solid #d9e9fe;
}

.dl-btn.btn-ghost .arrow {
    color: var(--primary);
}

.dl-btn.btn-ghost:hover {
    background: #e7f1ff;
    border-color: var(--primary-line);
    transform: translateY(-2px);
    box-shadow: var(--shadow-sm);
}

/* 信任信息行 */
.dl-trust {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: 8px 18px;
    margin-top: 24px;
    font-size: 12.5px;
    color: var(--muted);
}

.dl-trust .trust-item {
    display: inline-flex;
    align-items: center;
    gap: 6px;
}

.dl-trust svg {
    width: 15px;
    height: 15px;
    color: var(--primary);
}

/* ---------- 页脚 ---------- */
.site-footer {
    position: relative;
    z-index: 1;
    background: #0d1928;
    color: #93a3b5;
}

.footer-main {
    display: flex;
    flex-wrap: wrap;
    gap: 56px;
    padding: 56px 0 42px;
}

.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;
}

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

@media (max-width: 600px) {
    .container {
        padding: 0 16px;
    }

    .brand img {
        height: 34px;
    }

    .download-wrap {
        padding: calc(var(--nav-h) + 36px) 16px 60px;
    }

    .dl-card {
        padding: 34px 22px 30px;
        border-radius: var(--radius);
        animation-duration: .5s;
    }

    .dl-title {
        font-size: 23px;
    }

    .dl-qr {
        width: 184px;
    }

    .dl-btn {
        padding: 13px 18px;
        font-size: 15px;
    }

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

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

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

    html {
        scroll-behavior: auto;
    }
}