/* ============================================================
   7-Zip-zstd 全局样式系统
   配色：基于 logo 黑白色系，主黑 + 强调蓝
   ============================================================ */

/* ---------- CSS 变量 ---------- */
:root{
    --color-bg:        #FFFFFF;
    --color-bg-soft:   #F8FAFC;
    --color-bg-mute:   #F1F5F9;
    --color-border:    #E2E8F0;
    --color-border-soft:#EEF2F7;
    --color-text:      #0F172A;
    --color-text-soft: #475569;
    --color-text-mute: #94A3B8;

    --color-black:     #0A0A0A;
    --color-accent:    #3B82F6;
    --color-accent-dark:#1D4ED8;
    --color-accent-soft:#EFF6FF;
    --color-success:   #10B981;
    --color-warning:   #F59E0B;

    --radius-sm:  6px;
    --radius:     10px;
    --radius-lg:  16px;
    --radius-xl:  20px;

    --shadow-sm:  0 1px 2px rgba(15,23,42,0.04);
    --shadow:     0 4px 12px rgba(15,23,42,0.06);
    --shadow-lg:  0 10px 30px rgba(15,23,42,0.08);
    --shadow-xl:  0 20px 50px rgba(15,23,42,0.10);

    --container:  1200px;
    --header-h:   68px;

    --transition: 200ms cubic-bezier(.4,.0,.2,1);
    --font-sans:  -apple-system, BlinkMacSystemFont, "Segoe UI", "PingFang SC",
                  "Hiragino Sans GB", "Microsoft YaHei", "Helvetica Neue", Helvetica, Arial, sans-serif;
    --font-mono:  "JetBrains Mono", "Fira Code", "SF Mono", Consolas, Monaco, monospace;
}

/* ---------- 重置 ---------- */
*, *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body{
    margin:0;
    font-family: var(--font-sans);
    color: var(--color-text);
    background: var(--color-bg);
    line-height: 1.65;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}
img, svg { max-width: 100%; display: block; }
a { color: var(--color-accent); text-decoration: none; transition: color var(--transition); }
a:hover { color: var(--color-accent-dark); }
button { font-family: inherit; cursor: pointer; border: 0; background: none; padding: 0; }
ul, ol { margin: 0; padding: 0; list-style: none; }
h1, h2, h3, h4, h5, h6 { margin: 0; font-weight: 700; line-height: 1.3; color: var(--color-text); letter-spacing: -0.01em; }
p { margin: 0 0 1em; }
code, pre { font-family: var(--font-mono); font-size: 0.9em; }

/* ---------- 布局 ---------- */
.container{ max-width: var(--container); margin: 0 auto; padding: 0 24px; }
.section{ padding: 80px 0; }
.section-sm{ padding: 56px 0; }
.section-lg{ padding: 120px 0; }
@media (max-width: 768px){
    .section, .section-lg{ padding: 56px 0; }
    .section-sm{ padding: 40px 0; }
    .container{ padding: 0 16px; }
}

/* ---------- 通用 ---------- */
.text-mute{ color: var(--color-text-mute); }
.text-soft{ color: var(--color-text-soft); }
.text-center{ text-align: center; }
.text-mono{ font-family: var(--font-mono); }
.flex-center{ display:flex; align-items:center; justify-content:center; }

/* ---------- 按钮 ---------- */
.btn{
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 13px 28px;
    border-radius: var(--radius);
    font-size: 15px;
    font-weight: 600;
    text-decoration: none;
    transition: all var(--transition);
    border: 1px solid transparent;
    cursor: pointer;
    white-space: nowrap;
    line-height: 1.2;
}
.btn-primary{
    background: var(--color-black);
    color: #fff;
    box-shadow: 0 2px 6px rgba(10,10,10,0.18);
}
.btn-primary:hover{
    background: #1f1f1f;
    color: #fff;
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(10,10,10,0.24);
}
.btn-accent{
    background: var(--color-accent);
    color: #fff;
    box-shadow: 0 2px 6px rgba(59,130,246,0.24);
}
.btn-accent:hover{
    background: var(--color-accent-dark);
    color: #fff;
    transform: translateY(-1px);
    box-shadow: 0 6px 16px rgba(59,130,246,0.32);
}
.btn-outline{
    background: #fff;
    color: var(--color-text);
    border-color: var(--color-border);
}
.btn-outline:hover{
    border-color: var(--color-text);
    color: var(--color-text);
    background: var(--color-bg-soft);
}
.btn-ghost{
    background: transparent;
    color: var(--color-text);
}
.btn-ghost:hover{ background: var(--color-bg-mute); }
.btn-lg{ padding: 16px 36px; font-size: 16px; }
.btn-sm{ padding: 9px 18px; font-size: 13px; }
.btn-block{ display: flex; width: 100%; }

/* ---------- 导航栏 ---------- */
.site-header{
    position: sticky; top: 0; z-index: 100;
    background: rgba(255,255,255,0.85);
    backdrop-filter: saturate(180%) blur(14px);
    -webkit-backdrop-filter: saturate(180%) blur(14px);
    border-bottom: 1px solid var(--color-border-soft);
    height: var(--header-h);
}
.header-inner{
    display: flex; align-items: center; justify-content: space-between;
    height: 100%;
}
.brand{
    display: flex; align-items: center; gap: 12px;
    text-decoration: none;
    color: var(--color-text);
}
.brand-logo{
    width: 36px; height: 28px;
    background: var(--color-black);
    border-radius: 6px;
    display: flex; align-items: center; justify-content: center;
    color: #fff;
    font-weight: 900;
    font-size: 14px;
    letter-spacing: -0.5px;
    font-family: var(--font-mono);
}
.brand-text{ font-weight: 800; font-size: 17px; letter-spacing: -0.02em; }
.brand-text sub{ font-size: 10px; color: var(--color-text-mute); font-weight: 500; margin-left: 4px; }
.nav{ display: flex; align-items: center; gap: 4px; }
.nav a{
    padding: 8px 14px;
    color: var(--color-text-soft);
    font-size: 14px;
    font-weight: 500;
    border-radius: 8px;
    text-decoration: none;
    transition: all var(--transition);
}
.nav a:hover{ color: var(--color-text); background: var(--color-bg-mute); }
.nav a.active{ color: var(--color-text); background: var(--color-bg-mute); }
.nav-cta{ margin-left: 12px; }
.menu-toggle{ display: none; }
@media (max-width: 880px){
    .nav{ display: none; }
    .menu-toggle{
        display: flex; align-items: center; justify-content: center;
        width: 40px; height: 40px;
        border-radius: 8px;
        color: var(--color-text);
    }
    .menu-toggle:hover{ background: var(--color-bg-mute); }
    .nav.open{
        display: flex;
        position: absolute;
        top: var(--header-h); left: 0; right: 0;
        flex-direction: column;
        background: #fff;
        padding: 12px;
        gap: 4px;
        border-bottom: 1px solid var(--color-border);
        box-shadow: var(--shadow);
    }
    .nav.open a{ width: 100%; padding: 12px 14px; }
}

/* ---------- Hero ---------- */
.hero{
    padding: 80px 0 60px;
    background:
        radial-gradient(ellipse 80% 50% at 50% 0%, rgba(59,130,246,0.08), transparent 60%),
        linear-gradient(180deg, var(--color-bg) 0%, var(--color-bg-soft) 100%);
    position: relative;
    overflow: hidden;
}
.hero::before{
    content: "";
    position: absolute;
    inset: 0;
    background-image:
        linear-gradient(rgba(15,23,42,0.04) 1px, transparent 1px),
        linear-gradient(90deg, rgba(15,23,42,0.04) 1px, transparent 1px);
    background-size: 32px 32px;
    mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, transparent 80%);
    -webkit-mask-image: linear-gradient(180deg, rgba(0,0,0,1) 0%, transparent 80%);
    pointer-events: none;
}
.hero-grid{
    position: relative;
    display: grid;
    grid-template-columns: 1.1fr 1fr;
    gap: 60px;
    align-items: center;
}
@media (max-width: 980px){
    .hero-grid{ grid-template-columns: 1fr; gap: 40px; }
}
.hero-eyebrow{
    display: inline-flex; align-items: center; gap: 8px;
    padding: 6px 12px;
    background: rgba(59,130,246,0.10);
    color: var(--color-accent-dark);
    border-radius: 999px;
    font-size: 13px;
    font-weight: 600;
    margin-bottom: 22px;
}
.hero-eyebrow .dot{
    width: 6px; height: 6px; border-radius: 50%;
    background: var(--color-accent);
    box-shadow: 0 0 0 4px rgba(59,130,246,0.18);
}
.hero h1{
    font-size: clamp(34px, 5vw, 52px);
    line-height: 1.1;
    letter-spacing: -0.025em;
    margin-bottom: 22px;
}
.hero h1 .accent{
    background: linear-gradient(120deg, var(--color-accent) 0%, var(--color-accent-dark) 100%);
    -webkit-background-clip: text; background-clip: text;
    color: transparent;
}
.hero-sub{
    font-size: 18px;
    color: var(--color-text-soft);
    max-width: 540px;
    margin-bottom: 32px;
}
.hero-cta{ display: flex; gap: 14px; flex-wrap: wrap; }
.hero-meta{
    display: flex; gap: 28px; flex-wrap: wrap;
    margin-top: 36px;
    padding-top: 28px;
    border-top: 1px solid var(--color-border);
    font-size: 13px;
    color: var(--color-text-mute);
}
.hero-meta b{ color: var(--color-text); font-weight: 700; }

/* Hero 可视化卡片 */
.hero-visual{
    position: relative;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
}
.hero-visual-head{
    padding: 14px 18px;
    border-bottom: 1px solid var(--color-border);
    background: var(--color-bg-soft);
    display: flex; align-items: center; gap: 12px;
}
.hero-visual-dots{ display: flex; gap: 6px; }
.hero-visual-dots span{ width: 10px; height: 10px; border-radius: 50%; background: var(--color-border); }
.hero-visual-title{ font-size: 12px; color: var(--color-text-mute); font-family: var(--font-mono); }
.hero-visual-body{ padding: 24px; }
.compact-stat{
    display: flex; justify-content: space-between; align-items: center;
    padding: 12px 16px;
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    margin-bottom: 10px;
    background: var(--color-bg);
}
.compact-stat:last-child{ margin-bottom: 0; }
.compact-stat .label{ font-size: 13px; color: var(--color-text-soft); font-weight: 500; }
.compact-stat .value{
    font-family: var(--font-mono);
    font-size: 13px; font-weight: 700;
    color: var(--color-text);
    background: var(--color-bg-mute);
    padding: 4px 10px;
    border-radius: 6px;
}

/* 章节标题 */
.section-head{
    max-width: 720px;
    margin: 0 auto 56px;
    text-align: center;
}
.section-eyebrow{
    display: inline-block;
    padding: 4px 12px;
    background: var(--color-bg-mute);
    color: var(--color-text-soft);
    border-radius: 999px;
    font-size: 12px;
    font-weight: 600;
    letter-spacing: 0.04em;
    margin-bottom: 14px;
    text-transform: uppercase;
}
.section-head h2{
    font-size: clamp(28px, 4vw, 40px);
    letter-spacing: -0.02em;
    margin-bottom: 14px;
}
.section-head p{
    font-size: 17px;
    color: var(--color-text-soft);
}

/* ---------- 卡片 ---------- */
.card{
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 28px;
    transition: all var(--transition);
}
.card:hover{
    border-color: var(--color-text-mute);
    box-shadow: var(--shadow);
}
.card-icon{
    width: 48px; height: 48px;
    border-radius: 12px;
    background: var(--color-bg-mute);
    color: var(--color-text);
    display: flex; align-items: center; justify-content: center;
    margin-bottom: 18px;
}
.card-icon.accent{ background: var(--color-accent-soft); color: var(--color-accent-dark); }
.card h3{
    font-size: 18px;
    margin-bottom: 10px;
    letter-spacing: -0.01em;
}
.card p{
    font-size: 14.5px;
    color: var(--color-text-soft);
    line-height: 1.6;
    margin: 0;
}

/* 网格 */
.grid{
    display: grid;
    gap: 24px;
}
.grid-3{ grid-template-columns: repeat(3, 1fr); }
.grid-4{ grid-template-columns: repeat(4, 1fr); }
.grid-2{ grid-template-columns: repeat(2, 1fr); }
@media (max-width: 880px){
    .grid-3, .grid-4 { grid-template-columns: repeat(2, 1fr); }
}
@media (max-width: 580px){
    .grid-3, .grid-4, .grid-2 { grid-template-columns: 1fr; }
}

/* ---------- 算法对比表 ---------- */
.algo-table{
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}
.algo-table table{ width: 100%; border-collapse: collapse; }
.algo-table th, .algo-table td{
    padding: 16px 20px;
    text-align: left;
    border-bottom: 1px solid var(--color-border-soft);
    font-size: 14.5px;
}
.algo-table th{
    background: var(--color-bg-soft);
    font-weight: 600;
    color: var(--color-text-soft);
    font-size: 12px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.algo-table tbody tr:hover{ background: var(--color-bg-soft); }
.algo-table tbody tr:last-child td{ border-bottom: 0; }
.algo-name{ font-weight: 700; }
.algo-pill{
    display: inline-block;
    padding: 3px 10px;
    background: var(--color-bg-mute);
    border-radius: 999px;
    font-size: 12px;
    font-weight: 600;
    color: var(--color-text-soft);
    font-family: var(--font-mono);
}
@media (max-width: 720px){
    .algo-table{ overflow-x: auto; }
    .algo-table table{ min-width: 600px; }
}

/* ---------- 用户评价 ---------- */
.testimonial{
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 30px;
    position: relative;
}
.testimonial blockquote{
    margin: 0 0 22px 0;
    padding: 0;
    font-size: 15.5px;
    line-height: 1.7;
    color: var(--color-text);
}
.testimonial-author{
    display: flex; align-items: center; gap: 12px;
    padding-top: 16px;
    border-top: 1px solid var(--color-border-soft);
}
.avatar{
    width: 40px; height: 40px; border-radius: 50%;
    background: var(--color-bg-mute);
    color: var(--color-text-soft);
    display: flex; align-items: center; justify-content: center;
    font-weight: 700;
    font-size: 14px;
}
.testimonial-author .name{ font-weight: 600; font-size: 14.5px; }
.testimonial-author .role{ font-size: 12px; color: var(--color-text-mute); }
.stars{ display: inline-flex; gap: 2px; color: var(--color-warning); margin-bottom: 14px; }

/* ---------- 使用场景 ---------- */
.scenarios{
    background: var(--color-bg-soft);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-xl);
    padding: 36px;
}
.scenarios h3{ font-size: 22px; margin-bottom: 22px; }

/* ---------- 步骤条 ---------- */
.steps{
    counter-reset: step;
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 28px;
}
@media (max-width: 760px){ .steps{ grid-template-columns: 1fr; } }
.step{
    counter-increment: step;
    padding: 28px;
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    position: relative;
}
.step::before{
    content: counter(step, decimal-leading-zero);
    display: block;
    font-family: var(--font-mono);
    font-size: 32px;
    font-weight: 800;
    color: var(--color-accent);
    line-height: 1;
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}
.step h4{ font-size: 17px; margin-bottom: 10px; }
.step p{ margin: 0; font-size: 14.5px; color: var(--color-text-soft); }

/* ---------- Code block ---------- */
.code-block{
    background: #0F172A;
    color: #E2E8F0;
    border-radius: var(--radius);
    padding: 20px 22px;
    font-family: var(--font-mono);
    font-size: 14px;
    line-height: 1.7;
    overflow-x: auto;
    margin: 18px 0;
}
.code-block .c-prompt{ color: #94A3B8; user-select: none; }
.code-block .c-comment{ color: #64748B; font-style: italic; }
.code-block .c-flag{ color: #93C5FD; }
.code-block .c-str{ color: #86EFAC; }

/* ---------- Download list ---------- */
.dl-list{
    background: #fff;
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    overflow: hidden;
}
.dl-row{
    display: grid;
    grid-template-columns: 1.6fr 1fr auto;
    align-items: center;
    padding: 18px 22px;
    border-bottom: 1px solid var(--color-border-soft);
    gap: 16px;
    transition: background var(--transition);
}
.dl-row:hover{ background: var(--color-bg-soft); }
.dl-row:last-child{ border-bottom: 0; }
.dl-row .dl-name{ font-weight: 600; font-size: 15px; }
.dl-row .dl-meta{ font-size: 12px; color: var(--color-text-mute); font-family: var(--font-mono); margin-top: 4px; }
.dl-row .dl-tag{
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    padding: 3px 8px;
    border-radius: 4px;
    background: var(--color-bg-mute);
    color: var(--color-text-soft);
    margin-right: 6px;
    text-transform: uppercase;
    letter-spacing: 0.04em;
}
.dl-row .dl-tag.recommend{ background: var(--color-accent-soft); color: var(--color-accent-dark); }
@media (max-width: 720px){
    .dl-row{ grid-template-columns: 1fr; gap: 8px; }
    .dl-row .btn{ width: 100%; }
}

/* ---------- FAQ ---------- */
.faq-list{ max-width: 820px; margin: 0 auto; }
.faq-item{
    border-bottom: 1px solid var(--color-border-soft);
    padding: 22px 0;
}
.faq-item:first-child{ border-top: 1px solid var(--color-border-soft); }
.faq-q{
    display: flex; align-items: center; justify-content: space-between;
    cursor: pointer;
    font-weight: 600;
    font-size: 16px;
    color: var(--color-text);
    list-style: none;
    user-select: none;
}
.faq-q::-webkit-details-marker{ display: none; }
.faq-q::after{
    content: "";
    width: 14px; height: 14px;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%230F172A' stroke-width='2.5' stroke-linecap='round'><path d='M6 9l6 6 6-6'/></svg>");
    background-repeat: no-repeat;
    background-position: center;
    transition: transform var(--transition);
}
.faq-item[open] .faq-q::after{ transform: rotate(180deg); }
.faq-a{
    padding-top: 12px;
    color: var(--color-text-soft);
    font-size: 14.5px;
    line-height: 1.7;
}

/* ---------- 底部 CTA ---------- */
.cta-strip{
    background: var(--color-black);
    color: #fff;
    border-radius: var(--radius-xl);
    padding: 56px 48px;
    text-align: center;
    position: relative;
    overflow: hidden;
}
.cta-strip::before{
    content: "";
    position: absolute; inset: 0;
    background: radial-gradient(ellipse at center, rgba(59,130,246,0.18), transparent 60%);
    pointer-events: none;
}
.cta-strip > *{ position: relative; }
.cta-strip h2{ color: #fff; font-size: clamp(24px,3.5vw,32px); margin-bottom: 12px; }
.cta-strip p{ color: rgba(255,255,255,0.7); font-size: 16px; margin-bottom: 28px; }
.cta-strip .btn-primary{
    background: #fff; color: var(--color-black);
}
.cta-strip .btn-primary:hover{ background: #f1f5f9; }
.cta-strip .btn-outline{
    background: transparent; color: #fff; border-color: rgba(255,255,255,0.3);
}
.cta-strip .btn-outline:hover{ background: rgba(255,255,255,0.08); border-color: rgba(255,255,255,0.6); color: #fff; }

/* ---------- 页脚 ---------- */
.site-footer{
    background: var(--color-bg-soft);
    border-top: 1px solid var(--color-border);
    padding: 56px 0 24px;
    margin-top: 80px;
}
.footer-grid{
    display: grid;
    grid-template-columns: 1.4fr 1fr 1fr;
    gap: 40px;
    margin-bottom: 40px;
}
@media (max-width: 720px){ .footer-grid{ grid-template-columns: 1fr 1fr; } }
@media (max-width: 480px){ .footer-grid{ grid-template-columns: 1fr; } }
.footer-col h5{
    font-size: 13px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    color: var(--color-text);
    margin-bottom: 16px;
}
.footer-col a{
    display: block;
    color: var(--color-text-soft);
    font-size: 14px;
    padding: 6px 0;
    text-decoration: none;
}
.footer-col a:hover{ color: var(--color-accent); }
.footer-about{ font-size: 14px; color: var(--color-text-soft); margin-bottom: 18px; max-width: 340px; }
.footer-meta{
    padding-top: 24px;
    border-top: 1px solid var(--color-border);
    display: flex;
    justify-content: space-between;
    align-items: center;
    flex-wrap: wrap;
    gap: 16px;
    font-size: 13px;
    color: var(--color-text-mute);
}

/* ---------- 下载弹窗 ---------- */
.modal-backdrop{
    position: fixed; inset: 0; z-index: 1000;
    background: rgba(15,23,42,0.6);
    backdrop-filter: blur(4px);
    -webkit-backdrop-filter: blur(4px);
    display: none;
    align-items: center; justify-content: center;
    padding: 20px;
    animation: fadein 180ms ease-out;
}
.modal-backdrop.show{ display: flex;  left: 0;
  right: 0;
  top: 0;
  bottom: 0; }
  button { outline: none } 
@keyframes fadein{ from{ opacity:0 } to{ opacity:1 } }
.modal{
    background: #fff;
    border-radius: var(--radius-lg);
    width: 100%; max-width: 580px;
    overflow: hidden;
    box-shadow: var(--shadow-xl);
    animation: popup 220ms cubic-bezier(.4,0,.2,1);
}
@keyframes popup{ from{ transform:translateY(20px); opacity:0 } to{ transform:translateY(0); opacity:1 } }
.modal-head{
    padding: 22px 28px;
    border-bottom: 1px solid var(--color-border-soft);
    display: flex; align-items: center; justify-content: space-between;
}
.modal-title{ font-size: 18px; font-weight: 700; }
.modal-close{
    width: 32px; height: 32px;
    border-radius: 8px;
    display: flex; align-items: center; justify-content: center;
    color: var(--color-text-soft);
}
.modal-close:hover{ background: var(--color-bg-mute); color: var(--color-text); }
.modal-body{ padding: 28px; }
.modal-tip{
    margin: 0 0 22px 0;
    padding: 12px 14px;
    background: var(--color-accent-soft);
    color: var(--color-accent-dark);
    border-radius: var(--radius);
    font-size: 13px;
}
.qr-list{
    display: grid; grid-template-columns: 1fr 1fr; gap: 18px;
    margin-bottom: 22px;
}
.qr-card{
    border: 1px solid var(--color-border);
    border-radius: var(--radius);
    padding: 16px;
    text-align: center;
}
.qr-card .qr-img{
    width: 100%; aspect-ratio: 1;
    background: var(--color-bg-soft);
    border-radius: 8px;
    margin-bottom: 12px;
    display: flex; align-items: center; justify-content: center;
    overflow: hidden;
}
.qr-card .qr-img img,
.qr-card .qr-img svg{ width: 160px; height: 160px;}
.qr-card .qr-name{ font-size: 13px; font-weight: 600; }
.qr-card .qr-meta{ font-size: 11px; color: var(--color-text-mute); margin-top: 2px; }
.modal-actions{ display: flex; flex-direction: column; gap: 10px; }
.modal-foot{
    padding: 14px 28px 22px;
    text-align: center;
    font-size: 12px;
    color: var(--color-text-mute);
    border-top: 1px solid var(--color-border-soft);
}

/* ---------- Feature 单条 ---------- */
.feature-block{
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 56px;
    align-items: center;
    padding: 56px 0;
}
.feature-block.alt{ direction: rtl; }
.feature-block.alt > *{ direction: ltr; }
@media (max-width: 880px){
    .feature-block{ grid-template-columns: 1fr; gap: 32px; padding: 40px 0; }
}
.feature-block .f-eyebrow{
    display: inline-block;
    font-size: 12px;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--color-accent);
    margin-bottom: 12px;
}
.feature-block h3{
    font-size: clamp(24px,3vw,32px);
    margin-bottom: 16px;
    letter-spacing: -0.02em;
}
.feature-block p{
    color: var(--color-text-soft);
    font-size: 16px;
    margin-bottom: 20px;
}
.feature-bullets{ display: grid; gap: 12px; }
.feature-bullets li{
    display: flex; align-items: flex-start; gap: 10px;
    font-size: 14.5px;
    color: var(--color-text-soft);
}
.feature-bullets li::before{
    content: "";
    flex-shrink: 0;
    width: 18px; height: 18px;
    margin-top: 2px;
    background-image: url("data:image/svg+xml;utf8,<svg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 24 24' fill='none' stroke='%2310B981' stroke-width='2.5' stroke-linecap='round' stroke-linejoin='round'><polyline points='20 6 9 17 4 12'/></svg>");
    background-repeat: no-repeat;
    background-position: center;
}
.f-visual{
    background: var(--color-bg-soft);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    padding: 32px;
    min-height: 280px;
    display: flex; align-items: center; justify-content: center;
}

/* ---------- TOC / 锚点 ---------- */
.page-hero{
    padding: 64px 0 40px;
    background: var(--color-bg-soft);
    border-bottom: 1px solid var(--color-border);
}
.page-hero h1{
    font-size: clamp(32px,4.5vw,44px);
    letter-spacing: -0.02em;
    margin-bottom: 14px;
}
.page-hero p{
    font-size: 17px;
    color: var(--color-text-soft);
    max-width: 720px;
}
.page-hero .breadcrumb{
    font-size: 13px;
    color: var(--color-text-mute);
    margin-bottom: 14px;
}
.page-hero .breadcrumb a{ color: var(--color-text-soft); }
.page-hero .breadcrumb a:hover{ color: var(--color-accent); }
.page-hero .breadcrumb span{ margin: 0 8px; opacity: 0.6; }

/* 跳过链接 */
.skip-link{
    position: absolute;
    left: -9999px;
    top: 0;
    padding: 8px 12px;
    background: var(--color-black);
    color: #fff;
    z-index: 10000;
}
.skip-link:focus{ left: 12px; top: 12px; }