:root{--bg:#0b0f14;--fg:#e9edf1;--muted:#a3b0bb;--stroke:#293343;--od:#556b2f;--coyote:#8a6f3d;--blue:#3db2ff;--card:#101720;--card2:#0e141b;--shadow:0 10px 30px rgba(0,0,0,.4);--radius:18px;--maxw:1200px;--wm-opacity:.055;--link:var(--blue)}
:root.light{--bg:#f5f7f9;--fg:#0e1216;--muted:#5b6875;--stroke:#d4dde7;--card:#fff;--card2:#f7f9fb;--shadow:0 10px 24px rgba(0,0,0,.08);--wm-opacity:.08}
*{box-sizing:border-box}html,body{height:100%}body{margin:0;font-family:ui-sans-serif,system-ui,-apple-system,Segoe UI,Roboto,Ubuntu,Cantarell,Noto Sans,Helvetica Neue,Arial;background:var(--bg);color:var(--fg);line-height:1.65;-webkit-font-smoothing:antialiased;text-rendering:optimizeLegibility;position:relative}
body::before{content:"";position:fixed;inset:0;z-index:0;background-image:url('/assets/img/logo-watermark.png');background-position:center;background-repeat:no-repeat;background-size:min(80vmin,900px);opacity:var(--wm-opacity);pointer-events:none;filter:grayscale(100%)}
a{color:var(--link);text-underline-offset:2px}a:hover{opacity:.9}.wrap{max-width:var(--maxw);margin:0 auto;padding:0 20px;position:relative;z-index:1}
.site-header{position:sticky;top:0;z-index:10;background:color-mix(in hsl, var(--bg), transparent 15%);backdrop-filter:blur(8px);border-bottom:1px solid var(--stroke)}
.nav{height:64px;display:flex;align-items:center;justify-content:space-between}
.brand{display:flex;align-items:center;gap:12px;text-decoration:none;color:var(--fg);font-weight:800;letter-spacing:.3px;font-size:1.1rem}.brand img{width:34px;height:34px;border-radius:10px}
.nav-links a{margin-left:18px;color:var(--muted);text-decoration:none;font-weight:700}.nav-links a:hover{color:var(--fg)}
.theme-toggle{margin-left:14px;border:1px solid var(--stroke);background:var(--card);color:var(--fg);border-radius:999px;padding:8px 12px;cursor:pointer;font-weight:800}
.hero{padding:72px 0 36px}.grid{display:grid;gap:24px;grid-template-columns:1.2fr 1fr;align-items:center}@media (max-width:980px){.grid{grid-template-columns:1fr}}
h1{font-size:clamp(32px,3.6vw,56px);line-height:1.1;margin:0}.lead{font-size:clamp(16px,1.5vw,20px);color:var(--muted);margin:14px 0 24px}
.cta-row{display:flex;gap:12px;flex-wrap:wrap}.btn{display:inline-flex;align-items:center;gap:10px;padding:12px 18px;border-radius:14px;font-weight:800;text-decoration:none}
.btn svg{width:18px;height:18px}.btn.primary{background:linear-gradient(45deg,var(--od),var(--coyote));color:#fff;box-shadow:var(--shadow)}.btn.ghost{border:1px solid var(--stroke);color:var(--fg);background:var(--card)}
.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:22px}@media (max-width:1000px){.cards{grid-template-columns:1fr 1fr}}@media (max-width:700px){.cards{grid-template-columns:1fr}}
.card{background:var(--card);border:1px solid var(--stroke);border-radius:var(--radius);padding:18px;box-shadow:var(--shadow)}.card h3{margin-top:0}
.badge{display:inline-block;font-size:.75rem;letter-spacing:.5px;border:1px solid var(--stroke);background:var(--card2);padding:6px 10px;border-radius:999px;margin-right:8px}
.frame{border:1px solid var(--stroke);background:var(--card2);border-radius:16px;overflow:hidden;box-shadow:var(--shadow)}.frame img{width:100%;display:block}
.toc{background:var(--card);border:1px solid var(--stroke);border-radius:var(--radius);padding:16px}.help-section{margin:36px 0}.help-section h2{margin:0 0 8px}
.step{background:var(--card2);border:1px solid var(--stroke);border-radius:14px;padding:14px;margin:10px 0}figure{margin:14px 0}figcaption{color:var(--muted);font-size:.9rem;margin-top:6px}
.site-footer{margin-top:40px;padding:18px 0 40px;border-top:1px solid var(--stroke);color:var(--muted)}.small{font-size:.9rem;color:var(--muted)}.kicker{text-transform:uppercase;letter-spacing:.12em;font-weight:900;color:var(--coyote);font-size:.8rem}
.hr{height:1px;background:var(--stroke);margin:22px 0}.center{text-align:center}.anchor{scroll-margin-top:84px}
.hamburger{display:none;background:var(--card);border:1px solid var(--stroke);border-radius:12px;padding:8px 12px;color:var(--fg);font-weight:900}
@media (max-width:900px){.wrap{padding:0 14px}.nav{height:56px}.nav-links{display:none;position:absolute;right:14px;top:60px;background:var(--card);border:1px solid var(--stroke);border-radius:14px;padding:10px;box-shadow:var(--shadow)}.nav-links a,.nav .theme-toggle{display:block;margin:8px 0}.hamburger{display:inline-flex}.hero{padding:46px 0 18px}h1{font-size:clamp(26px,7vw,34px)}.lead{font-size:16px}.cta-row .btn{width:100%;justify-content:center;padding:12px 14px}.cards{grid-template-columns:1fr;gap:12px}.frame{border-radius:12px}body::before{background-size:110vmin;opacity:calc(var(--wm-opacity)*0.9)}}
.btn,.theme-toggle,.hamburger{min-height:44px}a,button{-webkit-tap-highlight-color:rgba(255,255,255,.1)}
ul.tight>li{margin:6px 0}