/* =====================================================================
   爱思助手下载 · 全站样式
   设计：克制、留白、苹果/ v2ex 风格 · 系统字体（零 webfont，利于加载与 SEO）
   响应式：手机 / 平板 / 桌面 / 超大屏 全适配
   ===================================================================== */

:root {
    --bg:           #f5f5f7;
    --surface:      #ffffff;
    --surface-2:    #fafafc;
    --text:         #1d1d1f;
    --text-2:       #6e6e73;
    --text-3:       #9a9aa1;
    --line:         rgba(0, 0, 0, .09);
    --line-2:       rgba(0, 0, 0, .06);

    --accent:       #0b67ff;
    --accent-press: #0a4fd0;
    --accent-soft:  rgba(11, 103, 255, .10);
    --warn:         #e0352b;
    --green:        #1aa06d;

    --r:    16px;
    --r-sm: 12px;
    --pill: 980px;

    --shadow-sm: 0 1px 2px rgba(0, 0, 0, .04);
    --shadow:    0 1px 2px rgba(0, 0, 0, .04), 0 10px 30px rgba(0, 0, 0, .055);
    --shadow-lg: 0 18px 50px rgba(0, 0, 0, .14);

    --container: 1080px;
    --space:     clamp(16px, 4vw, 28px);

    --font: -apple-system, BlinkMacSystemFont, "PingFang SC", "Hiragino Sans GB",
            "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
}

* { box-sizing: border-box; }

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

body {
    margin: 0;
    font-family: var(--font);
    color: var(--text);
    background: var(--bg);
    line-height: 1.65;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    text-rendering: optimizeLegibility;
}

a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

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

.container {
    width: 100%;
    max-width: var(--container);
    margin: 0 auto;
    padding-left: var(--space);
    padding-right: var(--space);
}

/* ----------------------------- 顶栏 ----------------------------- */
.site-header {
    position: sticky;
    top: 0;
    z-index: 50;
    background: rgba(255, 255, 255, .82);
    backdrop-filter: saturate(180%) blur(18px);
    -webkit-backdrop-filter: saturate(180%) blur(18px);
    border-bottom: 1px solid var(--line-2);
}
.header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 54px;
}
.brand { display: inline-flex; align-items: center; gap: 9px; color: var(--text); }
.brand:hover { text-decoration: none; }
.brand-mark {
    display: inline-grid;
    place-items: center;
    width: 28px; height: 28px;
    border-radius: 8px;
    background: linear-gradient(160deg, #4094ff, #0b67ff);
    color: #fff;
    font-weight: 700;
    font-size: 13px;
    letter-spacing: .2px;
}
.brand-name { font-weight: 600; font-size: 17px; letter-spacing: .2px; }
.top-nav { display: flex; gap: 22px; }
.top-nav a { color: var(--text-2); font-size: 14.5px; }
.top-nav a:hover { color: var(--text); text-decoration: none; }

/* ----------------------------- Hero（首页）----------------------------- */
.hero {
    text-align: center;
    padding: clamp(40px, 8vw, 78px) 0 clamp(22px, 4vw, 34px);
}
.hero h1 {
    margin: 0 0 14px;
    font-size: clamp(28px, 5.4vw, 46px);
    line-height: 1.12;
    letter-spacing: -.02em;
    font-weight: 700;
}
.hero p {
    margin: 0 auto;
    max-width: 640px;
    color: var(--text-2);
    font-size: clamp(15px, 2.4vw, 19px);
}
.hero .accent { color: var(--accent); }

/* ----------------------- 卡片网格（首页入口）----------------------- */
.cards {
    display: grid;
    grid-template-columns: 1fr;
    gap: 16px;
    padding-bottom: 8px;
}
.card {
    position: relative;
    background: var(--surface);
    border: 1px solid var(--line-2);
    border-radius: var(--r);
    padding: 24px 22px;
    box-shadow: var(--shadow-sm);
    transition: transform .18s ease, box-shadow .18s ease, border-color .18s ease;
    display: flex;
    flex-direction: column;
}
.card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow);
    border-color: rgba(11, 103, 255, .25);
}
.card h2 { margin: 2px 0 8px; font-size: 19px; font-weight: 650; letter-spacing: -.01em; }
.card p { margin: 0 0 16px; color: var(--text-2); font-size: 14.5px; flex: 1; }
.card .kw {
    color: var(--accent);
    font-weight: 600;
    background: var(--accent-soft);
    padding: 1px 6px;
    border-radius: 6px;
    white-space: nowrap;
}
.card .go {
    align-self: flex-start;
    font-weight: 600;
    font-size: 15px;
    color: var(--accent);
}
.card-stretched-link::after {
    content: "";
    position: absolute; inset: 0;
    border-radius: inherit;
}

/* --------------------- 子页：应用头 + 步骤 --------------------- */
.app-head { text-align: center; padding: clamp(30px, 6vw, 52px) 0 8px; }
.app-icon {
    width: 88px; height: 88px;
    border-radius: 20px;
    margin: 0 auto 16px;
    box-shadow: var(--shadow);
}
.app-head h1 { margin: 0 0 6px; font-size: clamp(24px, 4.6vw, 34px); letter-spacing: -.02em; font-weight: 700; }
.app-head .sub { margin: 0 auto; max-width: 560px; color: var(--text-2); font-size: 15.5px; }

.steps { max-width: 620px; margin: 26px auto 0; }
.step {
    background: var(--surface);
    border: 1px solid var(--line-2);
    border-radius: var(--r);
    padding: 26px 22px 28px;
    margin-bottom: 16px;
    box-shadow: var(--shadow-sm);
    text-align: center;
}
.step-label {
    display: inline-block;
    border-left: 4px solid var(--accent);
    padding: 0 0 0 10px;
    margin: 0 auto 18px;
    font-weight: 700;
    font-size: 15px;
    color: var(--text);
    letter-spacing: .02em;
    align-self: flex-start;
}
.step-label.is-green { border-left-color: var(--green); }
.step-lead { font-size: 17px; font-weight: 600; margin: 0 0 6px; }
.step-lead.warn { color: var(--warn); }
.step-fig { border-radius: var(--r-sm); border: 1px solid var(--line-2); margin: 4px auto 18px; }

/* 准备物料清单（盒子页） */
.prep-list { list-style: none; margin: 6px 0 4px; padding: 0; text-align: left; max-width: 460px; margin-inline: auto; }
.prep-list li {
    position: relative;
    padding: 9px 0 9px 30px;
    border-bottom: 1px solid var(--line-2);
    color: var(--text);
    font-size: 15px;
}
.prep-list li:last-child { border-bottom: 0; }
.prep-list li::before {
    content: "";
    position: absolute; left: 6px; top: 17px;
    width: 7px; height: 7px; border-radius: 50%;
    background: var(--accent);
}

/* ------------------------- 安装按钮 ------------------------- */
.install-btn {
    appearance: none;
    border: 0;
    cursor: pointer;
    font-family: inherit;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 9px;
    min-width: 220px;
    padding: 14px 30px;
    font-size: 17px;
    font-weight: 600;
    color: #fff;
    background: var(--accent);
    border-radius: var(--pill);
    box-shadow: 0 8px 22px rgba(11, 103, 255, .28);
    transition: transform .15s ease, box-shadow .15s ease, background .15s ease;
    letter-spacing: .02em;
}
.install-btn:hover { background: #1b73ff; transform: translateY(-1px); text-decoration: none; }
.install-btn:active { transform: translateY(0); box-shadow: 0 4px 12px rgba(11, 103, 255, .26); }
.install-btn.is-green { background: var(--green); box-shadow: 0 8px 22px rgba(26, 160, 109, .28); }
.install-btn.is-green:hover { background: #1cae77; }
.install-btn .ico { width: 22px; height: 22px; border-radius: 6px; }

.note-muted { color: var(--text-3); font-size: 13px; margin: 14px 0 0; }
.note-warn  { color: var(--warn);   font-size: 13px; margin: 14px 0 0; }

/* ------------------------- 密码弹窗 ------------------------- */
.modal-mask {
    position: fixed; inset: 0;
    background: rgba(0, 0, 0, .42);
    display: flex; align-items: center; justify-content: center;
    padding: 20px;
    z-index: 100;
    opacity: 0;
    transition: opacity .2s ease;
}
.modal-mask.open { opacity: 1; }
.modal {
    width: 100%; max-width: 360px;
    background: var(--surface);
    border-radius: 18px;
    padding: 26px 24px 22px;
    box-shadow: var(--shadow-lg);
    transform: translateY(10px) scale(.98);
    transition: transform .2s ease;
}
.modal-mask.open .modal { transform: translateY(0) scale(1); }
.modal h3 { margin: 0 0 6px; font-size: 19px; text-align: center; }
.modal .modal-tip { margin: 0 0 18px; text-align: center; color: var(--text-2); font-size: 13.5px; }
.modal label { display: block; font-size: 13px; color: var(--text-2); margin-bottom: 7px; }
.modal input {
    width: 100%;
    padding: 13px 14px;
    font-size: 16px;
    border: 1px solid var(--line);
    border-radius: var(--r-sm);
    background: var(--surface-2);
    color: var(--text);
    outline: none;
    transition: border-color .15s ease, box-shadow .15s ease;
}
.modal input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px var(--accent-soft); background: #fff; }
.modal .err { color: var(--warn); font-size: 13px; min-height: 18px; margin: 8px 2px 0; }
.modal-actions { display: flex; gap: 10px; margin-top: 12px; }
.btn {
    flex: 1;
    appearance: none; border: 0; cursor: pointer; font-family: inherit;
    padding: 13px 16px; font-size: 16px; font-weight: 600;
    border-radius: var(--r-sm);
    transition: background .15s ease, opacity .15s ease;
}
.btn-primary { background: var(--accent); color: #fff; }
.btn-primary:hover { background: #1b73ff; }
.btn-primary:disabled { opacity: .6; cursor: default; }
.btn-ghost { background: var(--surface-2); color: var(--text-2); border: 1px solid var(--line); }
.btn-ghost:hover { background: #f0f0f3; }
.get-pwd { display: block; text-align: center; margin-top: 16px; font-size: 14px; font-weight: 600; }

/* ------------------------- guide 内容区（置于安装区下方）------------------------- */
.guide {
    max-width: 760px;
    margin: clamp(34px, 7vw, 64px) auto 0;
    padding-top: clamp(26px, 5vw, 40px);
    border-top: 1px solid var(--line-2);
}
.guide h2 {
    font-size: clamp(20px, 3.4vw, 26px);
    margin: 34px 0 12px;
    letter-spacing: -.01em;
    font-weight: 700;
}
.guide h2:first-child { margin-top: 0; }
.guide h3 { font-size: 17px; margin: 22px 0 6px; font-weight: 650; }
.guide p { color: var(--text-2); margin: 0 0 14px; }
.guide a { font-weight: 600; }
.guide strong { color: var(--text); }

.compare {
    width: 100%;
    border-collapse: collapse;
    margin: 8px 0 18px;
    font-size: 14.5px;
    background: var(--surface);
    border: 1px solid var(--line-2);
    border-radius: var(--r-sm);
    overflow: hidden;
}
.compare th, .compare td { padding: 12px 14px; text-align: left; border-bottom: 1px solid var(--line-2); }
.compare th { background: var(--surface-2); font-weight: 650; color: var(--text); }
.compare tr:last-child td { border-bottom: 0; }
.compare td:first-child { color: var(--text); font-weight: 600; width: 28%; }

.faq h3 { position: relative; padding-left: 22px; }
.faq h3::before { content: "Q"; position: absolute; left: 0; top: 0; color: var(--accent); font-weight: 800; }

/* ----------------------------- 页脚 ----------------------------- */
.site-footer {
    margin-top: clamp(46px, 9vw, 88px);
    padding: 30px 0 38px;
    border-top: 1px solid var(--line-2);
    background: var(--surface);
    text-align: center;
}
.foot-links {
    display: flex; flex-wrap: wrap; gap: 8px 18px;
    justify-content: center;
    margin-bottom: 16px;
}
.foot-links a { color: var(--text-2); font-size: 13.5px; }
.foot-links a:hover { color: var(--accent); text-decoration: none; }
.foot-meta { color: var(--text-3); font-size: 12.5px; max-width: 640px; margin: 0 auto 10px; }
.foot-meta strong { color: var(--text-2); }
.foot-copy { color: var(--text-3); font-size: 12.5px; margin: 0; }
.foot-copy a { color: var(--text-3); }

/* ----------------------------- 入场动画 ----------------------------- */
@media (prefers-reduced-motion: no-preference) {
    .reveal { opacity: 0; transform: translateY(14px); animation: rise .6s cubic-bezier(.2,.7,.2,1) forwards; }
    .reveal.d1 { animation-delay: .05s; }
    .reveal.d2 { animation-delay: .12s; }
    .reveal.d3 { animation-delay: .19s; }
    .reveal.d4 { animation-delay: .26s; }
    .reveal.d5 { animation-delay: .33s; }
    @keyframes rise { to { opacity: 1; transform: none; } }
}

/* ----------------------------- 响应式 ----------------------------- */
/* 平板：双列卡片 */
@media (min-width: 600px) {
    .cards { grid-template-columns: repeat(2, 1fr); gap: 18px; }
}
/* 桌面：三列卡片，顶栏导航始终可见 */
@media (min-width: 900px) {
    .cards { grid-template-columns: repeat(3, 1fr); }
}
/* 超大屏：限制最大宽度，避免内容过度拉伸 */
@media (min-width: 1400px) {
    :root { --container: 1140px; }
}
/* 手机：精简顶栏导航 */
@media (max-width: 560px) {
    .top-nav { gap: 14px; }
    .top-nav a { font-size: 13px; }
    .install-btn { width: 100%; min-width: 0; }
    .modal-actions { flex-direction: column-reverse; }
}
@media (max-width: 380px) {
    .top-nav { display: none; }   /* 极窄屏隐藏导航，靠页脚内链与卡片导航 */
}