/* ── Reset & Base ── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  /* Notion-style warm palette */
  --c-text:#37352f;
  --c-text-2:#787774;
  --c-text-3:#9b9a97;
  --c-bg:#ffffff;
  --c-bg-soft:#f7f6f3;
  --c-bg-mute:#f1f1ef;
  --c-bg-hover:rgba(55,53,47,.04);
  --c-border:#e9e9e7;
  --c-divider:#e9e9e7;
  --c-link:#37352f;
  --c-code:#eb5757;
  --sidebar-w:clamp(180px, 18vw, 270px);
  --sidebar-content-w:180px;
  --header-h:52px;
  --content-max:780px;
  --font-sans:ui-sans-serif,-apple-system,BlinkMacSystemFont,"Segoe UI","Noto Sans TC","Noto Sans SC",Helvetica,"Apple Color Emoji",Arial,sans-serif;
  --font-mono:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,"Liberation Mono",monospace;
}
html{scroll-behavior:smooth;scroll-padding-top:calc(var(--header-h) + 24px)}
body{font-family:var(--font-sans);color:var(--c-text);background:var(--c-bg);line-height:1.5;-webkit-font-smoothing:antialiased;font-size:16px}
a{color:var(--c-link);text-decoration:none}
a:hover{text-decoration:underline}

/* ── Header ── */
.site-header{position:fixed;top:0;left:0;right:0;height:var(--header-h);background:#fff;border-bottom:1px solid var(--c-border);display:flex;align-items:center;padding:0 20px;z-index:100}
.site-header .logo{font-size:14px;font-weight:600;color:var(--c-text);display:flex;align-items:center;gap:6px}
.site-header .logo:hover{text-decoration:none}
.site-header nav{margin-left:auto;display:flex;align-items:center;gap:4px}
.site-header nav a{color:var(--c-text-2);font-size:14px;font-weight:500;padding:6px 12px;border-radius:6px;transition:background .12s}
.site-header nav a:hover{background:var(--c-bg-hover);text-decoration:none;color:var(--c-text)}
.menu-toggle{display:none;background:none;border:none;font-size:20px;cursor:pointer;color:var(--c-text);padding:4px 8px;border-radius:6px}
.menu-toggle:hover{background:var(--c-bg-hover)}
.lang-switch{background:none;border:1px solid var(--c-border);border-radius:6px;padding:4px 10px;font-size:12px;cursor:pointer;color:var(--c-text-2);transition:all .15s;margin-left:4px}
.lang-switch:hover{border-color:#ccc;color:var(--c-text)}

/* ── Layout ── */
.page-wrapper{display:flex;margin-top:var(--header-h);min-height:calc(100vh - var(--header-h))}

/* ── Sidebar ── */
.sidebar{position:fixed;top:var(--header-h);left:0;bottom:0;width:var(--sidebar-w);overflow-y:auto;padding:20px 4px 20px 16px;border-right:1px solid var(--c-border);background:#fff;z-index:50;transition:transform .25s ease}
.sidebar>*{margin-left:auto;width:140px;text-align:left}
.sidebar::-webkit-scrollbar{width:4px}
.sidebar::-webkit-scrollbar-thumb{background:var(--c-border);border-radius:4px}

/* Search */
.sidebar-search{position:relative;margin-bottom:12px}
.sidebar-search input{width:100%;padding:6px 10px 6px 30px;border:1px solid var(--c-border);border-radius:6px;font-size:13px;color:var(--c-text);background:var(--c-bg-soft);outline:none;transition:border-color .2s,background .2s}
.sidebar-search input:focus{border-color:#b4b4b0;background:#fff}
.sidebar-search input::placeholder{color:var(--c-text-3)}
.sidebar-search .search-icon{position:absolute;left:9px;top:50%;transform:translateY(-50%);color:var(--c-text-3);font-size:13px;pointer-events:none}

/* Nav groups */
.sidebar .group-title{font-size:13px;font-weight:700;color:var(--c-text);letter-spacing:.01em;padding:20px 0 6px;user-select:none;border-top:1px solid var(--c-border);margin-top:4px}
.sidebar .group-title:first-of-type{padding-top:4px;border-top:none;margin-top:0}
.sidebar a{display:block;padding:4px 0;border-radius:0;font-size:14px;color:var(--c-text-2);transition:color .12s;line-height:1.6}
.sidebar a:hover{color:var(--c-text);text-decoration:none;background:none}
.sidebar a.active{color:#2563eb;font-weight:500;background:none}
.sidebar a.hidden{display:none}

/* ── Main Content ── */
.main-content{margin-left:var(--sidebar-w);flex:1;padding:40px clamp(32px, 4vw, 64px) 80px clamp(40px, 4vw, 72px);max-width:calc(var(--content-max) + var(--sidebar-w) + 140px)}

.main-content h1{font-size:40px;font-weight:700;margin-bottom:4px;letter-spacing:-.02em;line-height:1.2;color:var(--c-text)}
.main-content .page-desc{font-size:16px;color:var(--c-text-2);margin-bottom:28px}
.main-content h2{font-size:24px;font-weight:600;margin-top:40px;margin-bottom:12px;padding-bottom:0;border-bottom:none;color:var(--c-text);line-height:1.3}
.main-content h3{font-size:20px;font-weight:600;margin-top:28px;margin-bottom:8px;color:var(--c-text);line-height:1.3}
.main-content h4{font-size:16px;font-weight:600;margin-top:20px;margin-bottom:6px;color:var(--c-text)}
.main-content p{margin-bottom:12px;color:var(--c-text);line-height:1.7}
.main-content ul,.main-content ol{margin-bottom:12px;padding-left:24px;line-height:1.7}
.main-content li{margin-bottom:4px}
.main-content strong{font-weight:600}
.main-content code{background:rgba(135,131,120,.15);padding:2px 5px;border-radius:3px;font-family:var(--font-mono);font-size:85%;color:var(--c-code)}
.main-content pre{background:var(--c-bg-soft);border:1px solid var(--c-border);border-radius:6px;padding:16px;overflow-x:auto;margin-bottom:16px}
.main-content pre code{background:none;padding:0;font-size:14px;line-height:1.6;color:var(--c-text)}
.main-content table{width:100%;border-collapse:collapse;margin-bottom:16px;font-size:14px}
.main-content th{background:var(--c-bg-soft);font-weight:600;text-align:left;padding:8px 12px;border:1px solid var(--c-border);font-size:14px}
.main-content td{padding:8px 12px;border:1px solid var(--c-border);font-size:14px}
.main-content tr:hover td{background:var(--c-bg-hover)}
.main-content img{max-width:100%;border-radius:6px}
.main-content a{color:var(--c-text);text-decoration:underline;text-decoration-color:rgba(55,53,47,.25);text-underline-offset:3px;transition:text-decoration-color .15s}
.main-content a:hover{text-decoration-color:var(--c-text)}

/* ── Callout boxes (Notion style) ── */
.callout{padding:16px 16px 16px 16px;border-radius:6px;margin-bottom:16px;font-size:15px;line-height:1.6}
.callout strong{display:block;margin-bottom:4px;font-size:15px}
.callout.tip{background:rgba(0,135,107,.06);color:var(--c-text)}
.callout.warning{background:rgba(203,145,47,.1);color:var(--c-text)}
.callout.info{background:rgba(46,124,209,.07);color:var(--c-text)}

/* ── Hero (index page) ── */
.hero{padding:64px 24px 48px;max-width:720px;margin:0 auto}
.hero h1{font-size:40px;font-weight:700;letter-spacing:-.02em;margin-bottom:12px;color:var(--c-text);line-height:1.2}
.hero .tagline{font-size:16px;color:var(--c-text-2);margin-bottom:28px;line-height:1.7}
.hero .actions{display:flex;gap:10px;flex-wrap:wrap}
.hero .actions a{display:inline-flex;align-items:center;padding:8px 20px;border-radius:6px;font-weight:500;font-size:14px;transition:all .15s}
.hero .actions .primary{background:var(--c-text);color:#fff}
.hero .actions .primary:hover{background:#555;text-decoration:none}
.hero .actions .secondary{border:1px solid var(--c-border);color:var(--c-text)}
.hero .actions .secondary:hover{border-color:#ccc;text-decoration:none}

/* Feature cards (index) */
.features-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(240px,1fr));gap:16px;padding:16px 24px 60px;max-width:720px;margin:0 auto}
.feature-card{background:#fff;border:1px solid var(--c-border);border-radius:8px;padding:20px;transition:box-shadow .2s}
.feature-card:hover{box-shadow:0 2px 12px rgba(55,53,47,.08)}
.feature-card .icon{font-size:24px;margin-bottom:8px}
.feature-card h3{font-size:14px;font-weight:600;margin-bottom:4px;color:var(--c-text)}
.feature-card p{font-size:14px;color:var(--c-text-2);line-height:1.55}

/* ── Footer ── */
.site-footer{text-align:center;padding:20px;color:var(--c-text-3);font-size:12px;border-top:1px solid var(--c-divider)}

/* ── Page nav ── */
.page-nav{display:flex;justify-content:space-between;margin-top:44px;padding-top:20px;border-top:1px solid var(--c-divider)}
.page-nav a{display:flex;flex-direction:column;padding:10px 14px;border:1px solid var(--c-border);border-radius:6px;max-width:48%;transition:border-color .15s}
.page-nav a:hover{border-color:#ccc;text-decoration:none}
.page-nav a .label{font-size:12px;color:var(--c-text-3);margin-bottom:2px}
.page-nav a .title{font-size:14px;font-weight:600;color:var(--c-text)}

/* ── Responsive ── */
@media(max-width:959px){
  .sidebar{transform:translateX(-100%);box-shadow:2px 0 12px rgba(0,0,0,.08)}
  .sidebar.open{transform:translateX(0)}
  .main-content{margin-left:0;padding:32px 24px 60px;max-width:none}
  .menu-toggle{display:block}
  .site-header nav a.hide-mobile{display:none}
}
@media(max-width:640px){
  .main-content{padding:24px 16px 48px}
  .main-content h1{font-size:28px}
  .main-content h2{font-size:20px}
  .main-content h3{font-size:17px}
  .hero{padding:32px 16px 28px}
  .hero h1{font-size:28px}
  .features-grid{grid-template-columns:1fr;padding:12px 16px 40px}
}
.backdrop{display:none;position:fixed;inset:0;background:rgba(0,0,0,.15);z-index:40}
.backdrop.show{display:block}

/* ── kbd tag ── */
kbd{background:rgba(135,131,120,.15);border:1px solid var(--c-border);border-radius:3px;padding:1px 5px;font-family:var(--font-mono);font-size:12px;color:var(--c-text)}