/* RelVectors AI 课程门户 · 共享样式
   主题：米黄 #f1eee6 + 文字 #111310 + 信号绿 #b8ef69
   与旧 1.1 主页配色一致，但布局按课程门户重新组织。
*/
:root{
  --bg:#f1eee6;
  --panel:#faf8f2;
  --ink:#111310;
  --muted:#656860;
  --line:#cac6bb;
  --dark:#121512;
  --soft:#e8e4da;
  --signal:#b8ef69;
  --signal2:#d9f5b0;
  --code-bg:#2a2620;
  --code-fg:#e8e4da;
}
*{box-sizing:border-box}
html{scroll-behavior:smooth}
body{margin:0;background:var(--bg);color:var(--ink);font-family:"Manrope","Noto Sans SC",ui-sans-serif,sans-serif;font-weight:400;line-height:1.65}
a{color:inherit;text-decoration:none}
button{font:inherit}
.wrap{width:min(1180px,calc(100% - 40px));margin:0 auto}
.mono{font-family:"IBM Plex Mono","JetBrains Mono",monospace}
.kicker{font:500 11px/1.2 "IBM Plex Mono",monospace;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}
code{font-family:"IBM Plex Mono",monospace;font-size:.92em;background:rgba(17,19,16,.05);padding:1px 5px;border-radius:4px}

/* ===== nav ===== */
nav{position:sticky;top:0;z-index:30;background:rgba(241,238,230,.94);backdrop-filter:blur(14px);border-bottom:1px solid rgba(17,19,16,.12)}
.nav-inner{height:66px;display:flex;align-items:center;justify-content:space-between;gap:24px}
.brand{display:inline-flex;align-items:center;gap:10px;font-size:20px;font-weight:600;letter-spacing:-.025em}
.brand-logo{height:32px;width:32px;border-radius:7px;display:block}
.links{display:flex;gap:22px;font-size:14px;font-weight:500;color:#33362f}
.links a:hover{color:var(--ink)}
.links a.active{color:var(--ink);border-bottom:1.5px solid var(--signal);padding-bottom:2px}
.actions{display:flex;gap:9px;align-items:center}
.btn,.btn2{display:inline-flex;align-items:center;justify-content:center;border-radius:9px;padding:11px 15px;font-weight:500;font-size:14px;border:1px solid var(--ink);transition:.15s}
.btn{background:var(--ink);color:#fff}
.btn:hover{background:#000}
.btn2{background:transparent}
.btn2:hover{background:var(--soft)}
.lang{border:1px solid var(--line);border-radius:999px;background:transparent;padding:7px 10px;cursor:pointer}

/* ===== hero (course portal) ===== */
.hero{padding:84px 0 56px;border-bottom:1px solid rgba(17,19,16,.1)}
.hero h1{font-size:46px;font-weight:600;letter-spacing:-.025em;line-height:1.15;margin:18px 0 18px}
.hero h1 em{font-style:normal;color:var(--ink);background:linear-gradient(transparent 60%,var(--signal) 60%);padding:0 4px}
.hero p.lead{font-size:18px;color:#33362f;max-width:760px;margin:0 0 28px}
.hero-actions{display:flex;gap:12px;flex-wrap:wrap}
.eyebrow{font:500 11px/1.2 "IBM Plex Mono",monospace;letter-spacing:.14em;text-transform:uppercase;color:var(--muted);margin-bottom:6px}

/* ===== section ===== */
.section{padding:80px 0;border-bottom:1px solid rgba(17,19,16,.08)}
.section h2{font-size:30px;font-weight:600;letter-spacing:-.02em;margin:0 0 8px}
.section .lead{font-size:17px;color:#33362f;max-width:780px;margin:0 0 36px}
.section-head{margin-bottom:40px}

/* ===== grid: paper cards ===== */
.papers{display:grid;grid-template-columns:1fr 1fr;gap:22px;margin-top:18px}
@media (max-width:720px){.papers{grid-template-columns:1fr}}
.paper-card{background:var(--panel);border:1px solid var(--line);border-radius:14px;padding:26px;display:flex;flex-direction:column;gap:14px;transition:.18s}
.paper-card:hover{border-color:var(--ink);transform:translateY(-2px)}
.paper-card .tag{font:500 10px/1 "IBM Plex Mono",monospace;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);background:var(--soft);padding:4px 8px;border-radius:4px;display:inline-block;width:fit-content}
.paper-card h3{font-size:21px;font-weight:600;margin:6px 0 4px;line-height:1.3}
.paper-card .meta{font-size:12px;color:var(--muted)}
.paper-card p{font-size:14.5px;color:#33362f;margin:0;line-height:1.6}
.paper-card .more{margin-top:auto;font-weight:500;font-size:14px;color:var(--ink);display:inline-flex;align-items:center;gap:4px}
.paper-card .more::after{content:"\2192";transition:transform .15s}
.paper-card:hover .more::after{transform:translateX(3px)}

/* ===== grid: course structure ===== */
.course-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-top:18px}
@media (max-width:920px){.course-grid{grid-template-columns:repeat(2,1fr)}}
@media (max-width:600px){.course-grid{grid-template-columns:1fr}}
.part-card{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:22px;display:flex;flex-direction:column;gap:10px}
.part-card .num{font:500 11px/1 "IBM Plex Mono",monospace;letter-spacing:.12em;text-transform:uppercase;color:var(--muted)}
.part-card h4{font-size:18px;font-weight:600;margin:0}
.part-card p{font-size:14px;color:#33362f;margin:0;line-height:1.6}
.part-card ul{margin:8px 0 0;padding:0;list-style:none;font-size:13.5px;color:#33362f;line-height:1.8}
.part-card ul li::before{content:"\B7";color:var(--muted);margin-right:6px}

/* ===== lab card (embed v2.0.5) ===== */
.lab-card{background:linear-gradient(180deg,var(--panel),var(--bg));border:1px solid var(--line);border-radius:18px;padding:32px;margin-top:18px;display:grid;grid-template-columns:1.3fr 1fr;gap:30px;align-items:center}
@media (max-width:820px){.lab-card{grid-template-columns:1fr}}
.lab-card h3{font-size:24px;font-weight:600;margin:6px 0 10px}
.lab-card p{font-size:15px;color:#33362f;margin:0 0 18px;line-height:1.6}
.lab-card .meta{font-size:12px;color:var(--muted);margin-bottom:6px}
.lab-card .preview{background:var(--code-bg);color:var(--code-fg);border-radius:10px;padding:14px 18px;font-family:"IBM Plex Mono",monospace;font-size:12.5px;line-height:1.7;white-space:pre-wrap;overflow:hidden}

/* ===== footer ===== */
footer{padding:48px 0 32px;color:var(--muted);font-size:13px}
footer .row{display:flex;justify-content:space-between;align-items:center;gap:16px;flex-wrap:wrap}
footer a{color:var(--muted);text-decoration:underline;text-decoration-color:rgba(101,104,96,.3)}
footer a:hover{color:var(--ink)}

/* ===== doc page (sub-pages) ===== */
.doc-page{padding:64px 0 96px}
.doc-page .eyebrow{margin-bottom:14px}
.doc-page h1{font-size:42px;font-weight:600;letter-spacing:-.025em;margin:0 0 14px;line-height:1.15}
.doc-page .subtitle{font-size:18px;color:#33362f;max-width:820px;margin:0 0 28px;line-height:1.55}
.doc-page .meta-bar{display:flex;gap:24px;flex-wrap:wrap;font-size:13px;color:var(--muted);padding:14px 18px;background:var(--panel);border:1px solid var(--line);border-radius:10px;margin-bottom:32px}
.doc-page h2{font-size:26px;font-weight:600;margin:40px 0 14px;letter-spacing:-.015em}
.doc-page h3{font-size:19px;font-weight:600;margin:28px 0 10px}
.doc-page p{font-size:16px;line-height:1.75;margin:0 0 14px;color:#1a1c18}
.doc-page ul,.doc-page ol{margin:0 0 16px;padding-left:22px;font-size:15.5px;line-height:1.75}
.doc-page li{margin-bottom:6px}
.doc-page strong{font-weight:600}
.doc-page blockquote{border-left:3px solid var(--signal);background:var(--panel);padding:12px 18px;margin:18px 0;border-radius:0 8px 8px 0;color:#33362f;font-size:15px}
.doc-page .back{font-size:13.5px;color:var(--muted);margin-bottom:20px;display:inline-block}
.doc-page .back:hover{color:var(--ink)}
.doc-page .formula{font-family:"IBM Plex Mono",monospace;font-size:15.5px;background:var(--panel);padding:14px 18px;border-radius:8px;border:1px solid var(--line);margin:14px 0;display:block;overflow-x:auto}

/* ===== highlight: signal ===== */
.signal{background:linear-gradient(transparent 60%,var(--signal) 60%);padding:0 3px}

/* ===== doc page (sub-pages) extensions ===== */
.back{font-size:13.5px;color:var(--muted);margin-bottom:20px;display:inline-block}
.back:hover{color:var(--ink)}
.meta-bar{display:flex;gap:24px;flex-wrap:wrap;font-size:13px;color:var(--muted);padding:14px 18px;background:var(--panel);border:1px solid var(--line);border-radius:10px;margin-bottom:32px}
.doc-page .subtitle{font-size:18px;color:#33362f;max-width:820px;margin:0 0 28px;line-height:1.55}
.doc-page pre{background:var(--code-bg);color:var(--code-fg);padding:16px 20px;border-radius:10px;overflow-x:auto;font-size:13.5px;line-height:1.7;margin:14px 0 22px;font-family:"IBM Plex Mono",monospace}
.doc-page pre code{background:transparent;padding:0;color:inherit}
.doc-page table{width:100%;border-collapse:collapse;margin:14px 0 24px;font-size:14.5px}
.doc-page th,.doc-page td{padding:10px 14px;text-align:left;border-bottom:1px solid var(--line);vertical-align:top}
.doc-page th{font:500 11px/1.2 "IBM Plex Mono",monospace;letter-spacing:.08em;text-transform:uppercase;color:var(--accent);background:var(--panel);border-bottom:1px solid var(--ink)}
.doc-page em{font-style:normal;background:linear-gradient(transparent 60%,var(--signal2) 60%);padding:0 3px}
.paper-nav{display:flex;justify-content:space-between;flex-wrap:wrap;gap:12px;margin-top:40px;padding-top:24px;border-top:1px solid var(--line);font-size:14.5px}
.paper-nav a{font-weight:500}

/* ===== hero h1 multi-line ===== */
.hero h1{white-space:pre-line}

/* ===== lab page ===== */
.lab-page{padding:56px 0 96px}
.lab-header{display:flex;justify-content:space-between;align-items:flex-end;gap:32px;flex-wrap:wrap;margin-bottom:36px}
.lab-header h1{font-size:46px;font-weight:600;letter-spacing:-.025em;margin:8px 0 14px;line-height:1.15}
.lab-header .subtitle{font-size:18px;color:#33362f;max-width:600px;margin:0}
.lab-actions{display:flex;gap:10px;flex-shrink:0}
.lab-steps{display:grid;grid-template-columns:repeat(3,1fr);gap:18px;margin-bottom:32px}
@media (max-width:900px){.lab-steps{grid-template-columns:1fr}}
.step{background:var(--panel);border:1px solid var(--line);border-radius:12px;padding:22px;display:flex;gap:14px}
.step .num{font:600 22px/1 "IBM Plex Mono",monospace;color:var(--accent);flex-shrink:0}
.step-body h3{font-size:16px;font-weight:600;margin:0 0 8px}
.step-body p{font-size:14px;color:#33362f;margin:0 0 8px;line-height:1.6}
.step-body .prompt{font:400 12.5px/1.6 "IBM Plex Mono",monospace;background:var(--soft);padding:8px 10px;border-radius:6px;color:var(--ink);display:block}
.lab-frame-wrap{border:1px solid var(--line);border-radius:14px;overflow:hidden;background:var(--code-bg);margin-bottom:48px}
.lab-frame-toolbar{display:flex;align-items:center;gap:8px;padding:10px 14px;background:#1a2535;color:rgba(255,255,255,.6);font:400 12px/1 "IBM Plex Mono",monospace}
.lab-frame-toolbar .dot{width:11px;height:11px;border-radius:50%;display:inline-block}
.lab-frame-toolbar .red{background:#ff5f57}
.lab-frame-toolbar .yellow{background:#febc2e}
.lab-frame-toolbar .green{background:#28c840}
.lab-frame-toolbar .url{margin-left:12px;flex:1;text-align:center;letter-spacing:.05em}
.lab-frame{display:block;width:100%;height:760px;border:0;background:var(--panel)}
.kv-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:18px;margin-bottom:32px}
@media (max-width:900px){.kv-grid{grid-template-columns:1fr}}
.kv{padding:20px;border:1px solid var(--line);border-radius:10px;background:var(--panel)}
.kv-k{font:500 11px/1.2 "IBM Plex Mono",monospace;letter-spacing:.12em;text-transform:uppercase;color:var(--muted);margin-bottom:8px}
.kv-v{font-size:14px;color:var(--ink);margin:0;line-height:1.6}
.kv-v code{font-size:13px}
.lab-page h2{font-size:24px;font-weight:600;margin:48px 0 16px;letter-spacing:-.015em}

/* ===== skill cards (course.html) ===== */
.skill-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px;margin:18px 0 12px}
@media (max-width:780px){.skill-grid{grid-template-columns:1fr}}
.skill-card{display:flex;gap:18px;padding:20px;border:1px solid var(--line);border-radius:12px;background:var(--panel);transition:.18s}
.skill-card:hover{border-color:var(--ink);transform:translateY(-2px)}
.skill-num{font:600 22px/1 "IBM Plex Mono",monospace;color:var(--accent);flex-shrink:0;min-width:36px}
.skill-body{flex:1;min-width:0}
.skill-body h4{font-size:16px;font-weight:600;margin:0 0 6px;letter-spacing:-.01em}
.skill-body p{font-size:13.5px;color:#33362f;margin:0 0 10px;line-height:1.6}
.skill-dl{font:500 12.5px/1 "IBM Plex Mono",monospace;letter-spacing:.04em;color:var(--accent);text-decoration:underline;text-decoration-color:rgba(42,111,84,.4);text-underline-offset:3px;text-decoration-thickness:1.5px;display:inline-flex;align-items:center;gap:4px;padding:5px 0}
.skill-dl:hover{color:var(--ink);text-decoration-color:var(--signal);text-decoration-thickness:2px}