:root{--bg:#f5f7fb;--surface:#fff;--surface2:#eef2f8;--text:#111827;--muted:#64748b;--line:#dce3ee;--accent:#ff6b35;--accent2:#2563eb;--dark:#0b1220;--good:#10b981;--shadow:0 18px 50px rgba(15,23,42,.08);--radius:22px}*{box-sizing:border-box}html{scroll-behavior:smooth}body{margin:0;background:var(--bg);color:var(--text);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,"Segoe UI",sans-serif;line-height:1.6}body.dark{--bg:#070b14;--surface:#0e1626;--surface2:#131e31;--text:#edf3ff;--muted:#9aa9bd;--line:#23324a;--shadow:0 22px 60px rgba(0,0,0,.3)}a{color:inherit;text-decoration:none}.site-header{position:sticky;top:0;z-index:50;background:color-mix(in srgb,var(--bg) 86%,transparent);backdrop-filter:blur(18px);border-bottom:1px solid var(--line)}.nav-shell{max-width:1240px;margin:auto;height:74px;display:flex;align-items:center;gap:24px;padding:0 24px}.brand{display:flex;align-items:center;gap:11px;min-width:205px}.brand-mark{width:38px;height:38px;border-radius:12px;display:grid;place-items:center;font-weight:900;background:linear-gradient(135deg,var(--accent),#ffad57);color:#fff;box-shadow:0 8px 24px rgba(255,107,53,.28)}.brand strong,.brand small{display:block;line-height:1.05}.brand small{color:var(--muted);font-size:11px;letter-spacing:.16em;text-transform:uppercase;margin-top:5px}.nav{display:flex;align-items:center;gap:4px;flex:1}.nav-link{padding:9px 11px;border-radius:10px;color:var(--muted);font-size:14px;font-weight:650}.nav-link:hover,.nav-link.active{background:var(--surface);color:var(--text);box-shadow:0 5px 16px rgba(15,23,42,.06)}.nav-actions{display:flex;gap:8px;align-items:center}select,.icon-btn,.menu-btn{border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:11px;padding:9px 10px}.icon-btn,.menu-btn{cursor:pointer}.menu-btn{display:none;font-size:20px}.shell{max-width:1240px;margin:auto;padding:0 24px}.hero{min-height:650px;display:grid;grid-template-columns:1.08fr .92fr;align-items:center;gap:54px;padding:72px 24px 90px;max-width:1240px;margin:auto}.eyebrow{display:inline-flex;align-items:center;gap:8px;padding:7px 10px;border:1px solid var(--line);background:var(--surface);border-radius:999px;color:var(--muted);font-weight:700;font-size:13px}.eyebrow i{width:8px;height:8px;background:var(--good);border-radius:50%;box-shadow:0 0 0 5px color-mix(in srgb,var(--good) 16%,transparent)}h1{font-size:clamp(42px,6vw,78px);line-height:.98;letter-spacing:-.045em;margin:22px 0 24px}.gradient-text{background:linear-gradient(90deg,var(--accent),#ff9a3d 38%,var(--accent2));-webkit-background-clip:text;color:transparent}.lead{font-size:20px;color:var(--muted);max-width:720px}.hero-actions{display:flex;gap:12px;flex-wrap:wrap;margin:32px 0}.btn{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:13px 18px;border-radius:13px;font-weight:800;border:1px solid var(--line);background:var(--surface)}.btn.primary{background:var(--text);color:var(--bg);border-color:var(--text)}.btn.accent{background:var(--accent);border-color:var(--accent);color:white}.stats{display:flex;gap:12px;flex-wrap:wrap}.stat{padding:12px 15px;border:1px solid var(--line);border-radius:14px;background:var(--surface);min-width:125px}.stat strong{font-size:22px;display:block}.stat span{font-size:12px;color:var(--muted);text-transform:uppercase;letter-spacing:.08em}.robot-card{position:relative;background:linear-gradient(155deg,#101827,#17243a);border-radius:34px;min-height:480px;overflow:hidden;box-shadow:0 30px 80px rgba(15,23,42,.28);color:#fff}.robot-grid{position:absolute;inset:0;background-image:linear-gradient(rgba(255,255,255,.05) 1px,transparent 1px),linear-gradient(90deg,rgba(255,255,255,.05) 1px,transparent 1px);background-size:34px 34px;mask-image:linear-gradient(to bottom,black,transparent 92%)}.orb{position:absolute;border-radius:50%;filter:blur(2px)}.orb.one{width:210px;height:210px;right:-60px;top:-50px;background:rgba(37,99,235,.32)}.orb.two{width:180px;height:180px;left:-70px;bottom:-40px;background:rgba(255,107,53,.27)}.robot-svg{position:absolute;inset:60px 44px 80px;width:calc(100% - 88px);height:calc(100% - 140px)}.robot-label{position:absolute;left:28px;right:28px;bottom:28px;display:flex;justify-content:space-between;align-items:end}.robot-label small{color:#9fb0c9}.robot-label strong{font-size:18px}.section{padding:90px 0}.section.alt{background:var(--surface)}.section-head{display:flex;justify-content:space-between;gap:30px;align-items:end;margin-bottom:34px}.section-head h2,.page-hero h1{font-size:clamp(34px,4.4vw,56px);line-height:1.04;letter-spacing:-.035em;margin:10px 0}.section-head p,.page-hero p{max-width:700px;color:var(--muted);font-size:18px}.cards{display:grid;grid-template-columns:repeat(3,1fr);gap:18px}.card{background:var(--surface);border:1px solid var(--line);border-radius:var(--radius);padding:26px;box-shadow:var(--shadow)}.card .icon{font-size:28px;margin-bottom:18px}.card h3{margin:0 0 9px;font-size:21px}.card p{margin:0;color:var(--muted)}.card .more{display:inline-block;margin-top:18px;font-weight:800;color:var(--accent2)}.phase-strip{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}.phase-mini{background:var(--surface2);border-radius:16px;padding:16px;border:1px solid var(--line)}.phase-mini b{display:block;font-size:14px}.phase-mini span{font-size:12px;color:var(--muted)}.page-hero{padding:70px 0 45px}.kicker{font-weight:800;color:var(--accent);text-transform:uppercase;letter-spacing:.14em;font-size:12px}.two-col{display:grid;grid-template-columns:1.15fr .85fr;gap:24px}.stack{display:grid;gap:18px}.checklist{list-style:none;margin:0;padding:0}.checklist li{padding:12px 0;border-bottom:1px solid var(--line);display:flex;gap:10px}.checklist li:before{content:'✓';color:var(--good);font-weight:900}.timeline{display:grid;gap:10px}.timeline-row{display:grid;grid-template-columns:90px 1fr;gap:16px;padding:15px 0;border-bottom:1px solid var(--line)}.timeline-row strong{color:var(--accent2)}.codebox{background:#08111f;color:#d8e7ff;border-radius:18px;padding:20px;overflow:auto;font:13px/1.7 ui-monospace,SFMono-Regular,Menlo,monospace}.toolbar{display:flex;gap:10px;flex-wrap:wrap;margin:22px 0}.search{flex:1;min-width:220px;border:1px solid var(--line);background:var(--surface);color:var(--text);border-radius:13px;padding:13px 15px;font-size:15px}.filter{border:1px solid var(--line);background:var(--surface);color:var(--muted);border-radius:999px;padding:10px 13px;font-weight:750;cursor:pointer}.filter.active{background:var(--text);color:var(--bg)}.module-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.module-card{background:var(--surface);border:1px solid var(--line);border-radius:18px;padding:19px;transition:.18s transform,.18s box-shadow}.module-card:hover{transform:translateY(-3px);box-shadow:var(--shadow)}.module-code{font-size:12px;color:var(--accent);font-weight:900;letter-spacing:.08em}.module-card h3{font-size:17px;line-height:1.3;margin:7px 0 10px}.module-card p{font-size:13px;color:var(--muted);margin:0}.module-meta{margin-top:14px;font-size:12px;color:var(--accent2);font-weight:800}.resource-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}.resource{display:flex;justify-content:space-between;gap:20px;align-items:center;background:var(--surface);border:1px solid var(--line);border-radius:17px;padding:18px}.resource small{display:block;color:var(--muted)}.tag{display:inline-flex;padding:4px 8px;border-radius:999px;background:var(--surface2);font-size:11px;font-weight:800;color:var(--muted)}.notice{border:1px solid color-mix(in srgb,var(--accent) 40%,var(--line));background:color-mix(in srgb,var(--accent) 8%,var(--surface));border-radius:18px;padding:18px}.module-page{padding:55px 0 80px}.crumbs{color:var(--muted);font-size:13px;margin-bottom:16px}.article{background:var(--surface);border:1px solid var(--line);border-radius:24px;padding:30px;box-shadow:var(--shadow)}.article h1{font-size:40px;margin:0 0 18px}.article h2{margin-top:30px}.article pre{background:#08111f;color:#d8e7ff;padding:18px;border-radius:14px;overflow:auto}.article code{font-family:ui-monospace,SFMono-Regular,Menlo,monospace}.article blockquote{border-left:4px solid var(--accent);margin-left:0;padding-left:16px;color:var(--muted)}.module-nav{display:flex;justify-content:space-between;margin-top:18px;gap:12px}.footer{max-width:1240px;margin:50px auto 0;border-top:1px solid var(--line);padding:34px 24px 45px;display:grid;grid-template-columns:1fr auto auto;gap:30px;color:var(--muted)}.footer p{margin:5px 0}.footer-links{display:flex;gap:18px}.footer-meta{font-size:12px}.empty{padding:30px;text-align:center;color:var(--muted);display:none}@media(max-width:980px){.nav{display:none;position:absolute;top:74px;left:16px;right:16px;background:var(--surface);padding:12px;border:1px solid var(--line);border-radius:16px;box-shadow:var(--shadow);flex-direction:column;align-items:stretch}.nav.open{display:flex}.menu-btn{display:block;margin-left:auto}.nav-actions{margin-left:0}.brand{min-width:auto}.hero{grid-template-columns:1fr;min-height:auto}.robot-card{min-height:390px}.cards,.module-grid{grid-template-columns:repeat(2,1fr)}.phase-strip{grid-template-columns:repeat(2,1fr)}.two-col{grid-template-columns:1fr}}@media(max-width:650px){.nav-shell{padding:0 14px}.brand span:last-child{display:none}.hero{padding:48px 18px 70px}.shell{padding:0 18px}.cards,.module-grid,.resource-grid{grid-template-columns:1fr}.phase-strip{grid-template-columns:1fr}.section{padding:65px 0}.section-head{display:block}.footer{grid-template-columns:1fr}.footer-links{flex-wrap:wrap}.timeline-row{grid-template-columns:70px 1fr}.robot-card{min-height:330px}.robot-svg{inset:45px 25px 75px;width:calc(100% - 50px);height:calc(100% - 120px)}}

/* WEB v2 FULL library */
.library-toolbar{align-items:center}.library-select{flex:0 0 210px;min-width:180px}.folder-filters{display:flex;gap:8px;flex-wrap:wrap;margin:0 0 20px}.filter span{opacity:.65;font-size:11px}.library-grid{display:grid;gap:8px}.library-row{display:grid;grid-template-columns:86px minmax(0,1fr) 90px 78px;gap:14px;align-items:center;background:var(--surface);border:1px solid var(--line);border-radius:14px;padding:13px 15px;transition:.15s transform,.15s box-shadow}.library-row:hover{transform:translateY(-1px);box-shadow:var(--shadow)}.file-badge{font-size:11px;font-weight:900;text-align:center;padding:6px 8px;border-radius:9px;background:var(--surface2);color:var(--accent2)}.file-main{min-width:0}.file-main b,.file-main small{display:block;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}.file-main b{font-size:14px}.file-main small{font-size:11px;color:var(--muted);margin-top:2px}.file-size{font-size:12px;color:var(--muted);text-align:right}.file-open{font-size:12px;font-weight:800;color:var(--accent2);text-align:right}@media(max-width:720px){.library-row{grid-template-columns:70px minmax(0,1fr);gap:9px}.file-size,.file-open{display:none}.library-select{flex:1 1 180px}}

/* WEB v3 — 19-level engineering roadmap */
.roadmap-hero{padding-bottom:56px}.roadmap-legend{display:flex;gap:16px;flex-wrap:wrap;margin-top:24px;color:var(--muted);font-size:12px;font-weight:800;text-transform:uppercase;letter-spacing:.06em}.roadmap-legend span{display:flex;align-items:center;gap:7px}.dot{width:9px;height:9px;border-radius:50%;display:inline-block}.dot.foundation,.level-tier.foundation{background:#10b981}.dot.advanced,.level-tier.advanced{background:#2563eb}.dot.research,.level-tier.research{background:#7c3aed}.dot.product,.level-tier.product{background:#f97316}.dot.enterprise,.level-tier.enterprise{background:#0f172a}.dark .dot.enterprise,.dark .level-tier.enterprise{background:#94a3b8;color:#0b1220}.level-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:18px}.level-card{background:var(--surface);border:1px solid var(--line);border-radius:24px;padding:24px;box-shadow:var(--shadow);display:flex;flex-direction:column;gap:17px;position:relative;overflow:hidden}.level-card:before{content:"";position:absolute;left:0;top:0;bottom:0;width:4px;background:linear-gradient(var(--accent),var(--accent2))}.level-top{display:flex;align-items:center;justify-content:space-between;gap:16px}.level-no{font-weight:950;font-size:12px;letter-spacing:.1em;margin-right:8px}.level-tier{display:inline-flex;padding:5px 8px;border-radius:999px;color:#fff;font-size:10px;font-weight:900;letter-spacing:.07em}.level-range{font-size:14px;color:var(--accent2)}.level-card h3{font-size:24px;line-height:1.15;margin:0;letter-spacing:-.02em}.level-block{background:var(--surface2);border-radius:16px;padding:16px}.level-block>b,.level-modules>b{font-size:12px;text-transform:uppercase;letter-spacing:.08em}.level-block ul{margin:8px 0 0;padding-left:19px;color:var(--muted);font-size:14px}.level-facts{display:grid;gap:10px}.level-facts>div{border-left:2px solid var(--line);padding-left:12px}.level-facts>div.gate{border-left-color:var(--accent)}.level-facts span{font-size:11px;font-weight:900;text-transform:uppercase;letter-spacing:.07em;color:var(--muted)}.level-facts p{font-size:14px;margin:3px 0 0}.level-modules{margin-top:auto}.module-chips{display:flex;flex-wrap:wrap;gap:6px;margin-top:9px}.module-chips a{font-size:11px;font-weight:850;padding:5px 8px;border:1px solid var(--line);border-radius:8px;background:var(--surface2);color:var(--accent2)}.module-chips a:hover{border-color:var(--accent2);background:var(--surface)}.level-open{width:100%;cursor:pointer}.btn.small{padding:10px 14px}.level-banner{margin:0 0 18px;padding:13px 16px;border:1px solid color-mix(in srgb,var(--accent2) 35%,var(--line));background:color-mix(in srgb,var(--accent2) 7%,var(--surface));border-radius:14px}.level-banner b,.level-banner span{display:block}.level-banner b{color:var(--accent2);font-size:13px}.level-banner span{color:var(--muted);font-size:13px;margin-top:2px}@media(max-width:850px){.level-grid{grid-template-columns:1fr}}@media(max-width:650px){.level-card{padding:19px}.level-card h3{font-size:21px}.level-top{align-items:flex-start}.roadmap-legend{gap:10px}}

/* WEB v3.1 — learning module prototype */
.module-learning .lead{font-size:1.08rem;line-height:1.75;max-width:920px;color:var(--muted)}
.module-meta-grid{display:grid;grid-template-columns:repeat(4,minmax(0,1fr));gap:12px;margin:24px 0 30px}
.module-meta-grid>div{border:1px solid var(--line);border-radius:16px;padding:14px 16px;background:var(--card,#fff);display:flex;flex-direction:column;gap:4px}
.module-meta-grid span{color:var(--muted);font-size:.92rem}
.learning-block{margin:22px 0 26px}
.lesson-accordion{border:1px solid var(--line);border-radius:18px;background:var(--card,#fff);margin:14px 0;overflow:hidden}
.lesson-accordion summary{list-style:none;cursor:pointer;display:flex;align-items:center;gap:14px;padding:18px 20px;font-size:1.05rem;user-select:none}
.lesson-accordion summary::-webkit-details-marker{display:none}
.lesson-accordion summary>span{font-size:1.45rem}
.lesson-accordion summary>div{display:flex;flex-direction:column;gap:2px;flex:1}
.lesson-accordion summary small{font-weight:400;color:var(--muted)}
.lesson-accordion summary:after{content:'＋';font-size:1.4rem;color:var(--muted)}
.lesson-accordion[open] summary:after{content:'−'}
.lesson-accordion[open] summary{border-bottom:1px solid var(--line)}
.lesson-content{padding:20px 24px 24px;line-height:1.7}
.lesson-content h3{margin:20px 0 8px}
.lesson-content h3:first-child{margin-top:0}
.warning-box{margin-top:18px;border:1px solid #f0ad95;border-radius:14px;padding:14px 16px;background:#fff3ef}
[data-theme="dark"] .warning-box{background:rgba(255,99,51,.08)}
.theory-table-wrap{overflow-x:auto;margin:14px 0}
.theory-table{width:100%;border-collapse:collapse;min-width:620px}
.theory-table th,.theory-table td{padding:11px 12px;border:1px solid var(--line);text-align:left;vertical-align:top}
.theory-table th{background:rgba(99,116,150,.08)}
.procedure-list li,.acceptance-list li{margin:7px 0}
@media(max-width:800px){.module-meta-grid{grid-template-columns:repeat(2,minmax(0,1fr))}}
@media(max-width:520px){.module-meta-grid{grid-template-columns:1fr}.lesson-accordion summary{padding:15px}.lesson-content{padding:16px}}