:root{
  color-scheme:light;
  --ink:#16201c; --ink-2:#3d4a44; --muted:#66736d; --line:#e3e6df;
  --paper:#fbfaf6; --card:#ffffff; --lemon:#f5d02e; --lemon-soft:#fdf4c4;
  --leaf:#2f5d4a; --leaf-soft:#e7efe9;
  --on-lemon:#16201c; --on-lemon-2:#3d4a44;
  --btn-bg:#16201c; --btn-fg:#ffffff; --btn-hover:#000000;
  --nav-bg:rgba(251,250,246,.92); --thead:#f6f5ef; --shadow:rgba(22,32,28,.06);
  --leak-bg:#fde8e4; --leak-fg:#9b2f1d;
  --band:#16201c; --band-card:#1f2b26; --band-line:#2e3c35; --band-text:#c9d3cd; --band-head:#ffffff;
  --radius:14px; --max:1120px;
}
@media (prefers-color-scheme:dark){
  :root{
    color-scheme:dark;
    --ink:#eaf0ec; --ink-2:#bcc7c1; --muted:#8d9a93; --line:#2a3530;
    --paper:#111714; --card:#18201c; --lemon:#f5d02e; --lemon-soft:#3a3412;
    --leaf:#8fcaa9; --leaf-soft:#1d3329;
    --btn-bg:#f5d02e; --btn-fg:#16201c; --btn-hover:#ffe066;
    --nav-bg:rgba(17,23,20,.9); --thead:#1d2622; --shadow:rgba(0,0,0,.35);
    --leak-bg:#3d1f1a; --leak-fg:#f3a596;
    --band:#0b100e; --band-card:#161e1a; --band-line:#26312c; --band-text:#bcc7c1; --band-head:#ffffff;
  }
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--paper);color:var(--ink);font:16px/1.6 Inter,system-ui,-apple-system,Segoe UI,Roboto,sans-serif;-webkit-font-smoothing:antialiased}
a{color:var(--leaf)}
.wrap{max-width:var(--max);margin:0 auto;padding:0 20px}
h1,h2,h3{line-height:1.2;margin:0 0 .5em}
h1,h2{font-family:Fraunces,Georgia,serif;font-weight:700;letter-spacing:-.01em}
h1{font-size:clamp(2.1rem,4.6vw,3.4rem)}
h2{font-size:clamp(1.6rem,3vw,2.3rem)}
h3{font-size:1.1rem;font-weight:600}
p{margin:0 0 1em}
.eyebrow{display:inline-block;font-size:.8rem;font-weight:600;letter-spacing:.08em;text-transform:uppercase;color:var(--leaf);margin-bottom:.8rem}
.lead{font-size:1.15rem;color:var(--ink-2);max-width:40em}
section{padding:84px 0;border-top:1px solid var(--line)}
section:first-of-type{border-top:0}

/* nav */
header.nav{position:sticky;top:0;z-index:10;background:var(--nav-bg);backdrop-filter:blur(8px);border-bottom:1px solid var(--line)}
.nav .wrap{display:flex;align-items:center;justify-content:space-between;height:64px;gap:16px}
.brand{display:flex;align-items:center;gap:10px;text-decoration:none;color:var(--ink);font-weight:700;letter-spacing:-.01em}
.brand img{display:block;height:46px;width:auto}
.nav ul{display:flex;gap:26px;list-style:none;margin:0;padding:0;font-size:.95rem}
.nav ul a{color:var(--ink-2);text-decoration:none}
.nav ul a:hover{color:var(--ink)}
.btn{display:inline-block;padding:12px 20px;border-radius:999px;background:var(--btn-bg);color:var(--btn-fg);text-decoration:none;font-weight:600;font-size:.95rem;border:1px solid var(--btn-bg)}
.btn:hover{background:var(--btn-hover);border-color:var(--btn-hover)}
.btn.ghost{background:transparent;color:var(--ink);border-color:var(--ink)}
.btn.ghost:hover{background:var(--card)}
.brand,.btn{white-space:nowrap}
@media (max-width:820px){.nav ul{display:none}}
@media (max-width:420px){.nav .btn{padding:9px 14px;font-size:.85rem}.brand{font-size:.95rem}}

/* hero */
.hero{padding:88px 0 72px}
.hero-grid{display:grid;grid-template-columns:1.25fr .9fr;gap:56px;align-items:center}
.hero .ctas{display:flex;gap:12px;flex-wrap:wrap;margin-top:28px}
.hero h1 mark{background:linear-gradient(transparent 60%,var(--lemon) 60%);color:inherit;padding:0 .08em}
.stack-card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:22px;box-shadow:0 10px 30px var(--shadow)}
.stack-card .row{display:flex;align-items:center;gap:12px;padding:12px 0;border-bottom:1px dashed var(--line);font-size:.95rem}
.stack-card .row:last-child{border-bottom:0}
.dot{width:10px;height:10px;border-radius:50%;flex:none}
.tag{margin-left:auto;font-size:.75rem;font-weight:600;padding:3px 9px;border-radius:999px;white-space:nowrap}
.tag.leak{background:var(--leak-bg);color:var(--leak-fg)}
.tag.fix{background:var(--leaf-soft);color:var(--leaf)}
.stack-card .cap{font-size:.8rem;color:var(--muted);margin:0 0 6px}
@media (max-width:900px){.hero-grid{grid-template-columns:1fr}}

/* grids */
.grid{display:grid;gap:20px}
.g3{grid-template-columns:repeat(3,1fr)}
.g4{grid-template-columns:repeat(4,1fr)}
.g2{grid-template-columns:repeat(2,1fr)}
@media (max-width:900px){.g3,.g4{grid-template-columns:1fr 1fr}}
@media (max-width:620px){.g2,.g3,.g4{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--line);border-radius:var(--radius);padding:24px}
.card p{color:var(--ink-2);margin:0}
.card ul{margin:.6em 0 0;padding-left:1.1em;color:var(--ink-2)}
.card li{margin:.25em 0}
.icon{width:40px;height:40px;border-radius:10px;background:var(--lemon-soft);display:grid;place-items:center;margin-bottom:14px}
.icon svg{width:22px;height:22px;stroke:var(--ink);fill:none;stroke-width:1.8;stroke-linecap:round;stroke-linejoin:round}
.sec-head{max-width:46em;margin-bottom:36px}

/* pains */
.pains .card{border-left:4px solid var(--lemon)}
.pains .card p{font-size:1rem}

/* steps */
.steps{counter-reset:s}
.step{position:relative;padding-top:54px}
.step::before{counter-increment:s;content:counter(s);position:absolute;top:20px;left:24px;font-family:Fraunces,Georgia,serif;font-weight:700;font-size:1.3rem;width:36px;height:36px;border-radius:50%;background:var(--btn-bg);color:var(--btn-fg);display:grid;place-items:center;line-height:1}
.step .out{display:block;margin-top:12px;font-size:.85rem;color:var(--leaf);font-weight:600}

/* principles */
.dark{background:var(--band);color:var(--band-text);border-top:0}
.dark h2,.dark h3{color:var(--band-head)}
.dark .eyebrow{color:var(--lemon)}
.dark .lead{color:var(--band-text)}
.dark .card{background:var(--band-card);border-color:var(--band-line)}
.dark .card p{color:var(--band-text)}
.dark .icon{background:var(--band-line)}
.dark .icon svg{stroke:var(--lemon)}

/* compare */
.table-wrap{overflow-x:auto;border:1px solid var(--line);border-radius:var(--radius);background:var(--card)}
table{border-collapse:collapse;width:100%;min-width:680px;font-size:.95rem}
th,td{text-align:left;padding:14px 18px;border-bottom:1px solid var(--line);vertical-align:top}
thead th{font-size:.85rem;color:var(--muted);font-weight:600;background:var(--thead)}
tbody tr:last-child td{border-bottom:0}
td:first-child{font-weight:600}
th.us,td.us{background:var(--lemon-soft)}

/* faq */
details{background:var(--card);border:1px solid var(--line);border-radius:12px;padding:18px 22px;margin-bottom:12px}
summary{cursor:pointer;font-weight:600;list-style:none;display:flex;justify-content:space-between;gap:16px}
summary::-webkit-details-marker{display:none}
summary::after{content:"+";font-size:1.3rem;line-height:1;color:var(--muted)}
details[open] summary::after{content:"–"}
details p{margin:12px 0 0;color:var(--ink-2)}

/* cta */
.cta-box{background:var(--lemon);border-radius:22px;padding:56px 40px;display:grid;grid-template-columns:1.4fr 1fr;gap:32px;align-items:center}
.cta-box,.cta-box h2{color:var(--on-lemon)}
.cta-box p{color:var(--on-lemon-2)}
.mail{font-family:Fraunces,Georgia,serif;font-size:clamp(1.3rem,2.6vw,1.9rem);font-weight:700;color:var(--on-lemon);text-decoration:none;word-break:break-all}
.mail:hover{text-decoration:underline}
@media (max-width:820px){.cta-box{grid-template-columns:1fr;padding:40px 24px}}

footer{padding:40px 0 56px;color:var(--muted);font-size:.9rem}
footer .wrap{display:flex;justify-content:space-between;gap:20px;flex-wrap:wrap}

/* i18n */
html[lang^="zh"] body{font-family:Inter,"PingFang SC","PingFang TC","Hiragino Sans GB","Microsoft YaHei","Noto Sans CJK SC",system-ui,sans-serif;line-height:1.75}
html[lang="zh-Hant"] body{font-family:Inter,"PingFang TC","PingFang HK","Microsoft JhengHei","Noto Sans CJK TC",system-ui,sans-serif}
html[lang^="zh"] h1,html[lang^="zh"] h2{font-family:Fraunces,"Songti SC","Songti TC","Noto Serif CJK SC",Georgia,serif;letter-spacing:0}
html[lang^="zh"] .eyebrow{letter-spacing:.12em}
.nav-right{display:flex;align-items:center;gap:14px}
.lang{display:flex;gap:2px;border:1px solid var(--line);border-radius:999px;padding:3px;background:var(--card)}
.lang a{padding:4px 10px;border-radius:999px;font-size:.8rem;text-decoration:none;color:var(--ink-2);white-space:nowrap}
.lang a[aria-current="true"]{background:var(--btn-bg);color:var(--btn-fg)}
@media (max-width:520px){.nav .btn{display:none}.brand span{display:none}}

.cta-box .btn{background:#16201c;color:#fff;border-color:#16201c}
.cta-box .btn:hover{background:#000;border-color:#000}

/* pain -> fix, kicker, hero examples */
.pf h3{font-weight:600;color:var(--muted);text-decoration:line-through;text-decoration-color:var(--lemon);text-decoration-thickness:2px}
.pf .fix{color:var(--ink);font-weight:600;font-size:1.02rem}
.pf .fix::before{content:"→ ";color:var(--leaf)}
.kicker{display:inline-block;font-size:.72rem;font-weight:700;letter-spacing:.06em;text-transform:uppercase;color:var(--leaf);background:var(--leaf-soft);padding:2px 8px;border-radius:6px;margin-bottom:8px}
.examples{list-style:none;padding:0;margin:4px 0 0;display:grid;gap:8px}
.examples li{position:relative;padding-left:26px;color:var(--ink)}
.examples li::before{content:"";position:absolute;left:0;top:.5em;width:14px;height:8px;border-left:2.5px solid var(--leaf);border-bottom:2.5px solid var(--leaf);transform:rotate(-45deg)}

@media (prefers-color-scheme:dark){.hero h1 mark{background:none;color:var(--lemon)}}