@import url('https://fonts.googleapis.com/css2?family=Chakra+Petch:wght@500;600;700&family=Noto+Sans+TC:wght@400;500;600;700;900&display=swap');
:root{--bg:#06110f;--panel:#0e241e;--panel2:#102b24;--line:rgba(112,255,197,.14);--text:#effff8;--muted:#9cb8ad;--mint:#59f2b3;--cyan:#50dfff;--gold:#efc965;--top:70px;--side:310px;--shadow:0 20px 58px rgba(0,0,0,.34)}
*{box-sizing:border-box}html,body{margin:0;min-height:100%;background:var(--bg);color:var(--text);font-family:"Noto Sans TC",sans-serif}button,input{font:inherit}button{color:inherit}a{color:inherit;text-decoration:none}
.topbar{position:fixed;z-index:100;top:0;left:0;right:0;height:var(--top);display:grid;grid-template-columns:var(--side) 1fr auto;align-items:center;gap:16px;padding:0 18px;border-bottom:1px solid var(--line);background:rgba(5,17,14,.93);backdrop-filter:blur(16px)}
.brand-wrap,.brand{display:flex;align-items:center;gap:10px}.brand-mark{display:grid;width:43px;height:43px;place-items:center;border-radius:11px;background:linear-gradient(135deg,var(--mint),var(--cyan));color:#04120e;font:800 15px "Chakra Petch",sans-serif;box-shadow:0 0 24px rgba(89,242,179,.25)}.brand strong,.brand small{display:block}.brand strong{font-size:15px}.brand small{color:var(--muted);font-size:11px;letter-spacing:.12em}
.topnav{display:flex;justify-content:center;gap:4px;overflow:auto}.topnav-btn{padding:9px 12px;border:0;border-radius:9px;background:transparent;color:#bad1c7;cursor:pointer;white-space:nowrap}.topnav-btn:hover,.topnav-btn.active{color:var(--mint);background:rgba(89,242,179,.08)}
.ghost-btn,.icon-btn,.primary-btn,.secondary-btn,.nav-btn{border:0;cursor:pointer}.ghost-btn{padding:9px 13px;border:1px solid rgba(255,255,255,.1);border-radius:9px;background:rgba(255,255,255,.03);color:#c1d5cd}.icon-btn{display:grid;width:40px;height:40px;place-items:center;border:1px solid rgba(255,255,255,.1);border-radius:9px;background:rgba(255,255,255,.03)}.mobile-only{display:none}
.app-shell{display:grid;grid-template-columns:var(--side) 1fr;min-height:100vh;padding-top:var(--top)}
.sidebar{position:fixed;z-index:80;top:var(--top);bottom:0;left:0;width:var(--side);display:flex;flex-direction:column;border-right:1px solid var(--line);background:linear-gradient(rgba(7,24,19,.95),rgba(7,24,19,.98)),url('images/pcb-background.png') center/cover no-repeat}.sidebar-title{display:flex;align-items:center;justify-content:space-between;padding:18px 18px 12px;font-weight:700}.search-box{padding:0 14px 14px}.search-box input{width:100%;padding:11px 12px;border:1px solid rgba(255,255,255,.1);border-radius:10px;outline:none;background:rgba(0,0,0,.18);color:white}.search-box input:focus{border-color:rgba(89,242,179,.42);box-shadow:0 0 0 3px rgba(89,242,179,.08)}
.accordion{flex:1;overflow:auto;padding:0 10px 18px}.group{margin:5px 0;border:1px solid transparent;border-radius:12px;overflow:hidden}.group.open{border-color:rgba(89,242,179,.12);background:rgba(255,255,255,.025)}.group-title{width:100%;display:grid;grid-template-columns:30px 1fr 20px;align-items:center;gap:8px;padding:11px 10px;border:0;background:transparent;color:#c9dfd6;text-align:left;cursor:pointer}.group-title:hover{color:white}.group-no{color:var(--gold);font:700 12px "Chakra Petch",sans-serif}.chev{color:var(--muted);transition:.2s}.group.open .chev{transform:rotate(90deg)}.group-items{display:grid;max-height:0;overflow:hidden;transition:max-height .25s ease}.group.open .group-items{max-height:800px}.topic-link{width:100%;padding:8px 12px 8px 48px;border:0;background:transparent;color:#91afa3;text-align:left;cursor:pointer}.topic-link:hover,.topic-link.active{color:var(--mint);background:linear-gradient(90deg,rgba(89,242,179,.08),transparent)}.sidebar-foot{display:flex;align-items:center;gap:8px;padding:15px 18px;border-top:1px solid var(--line);color:#8da89d;font-size:12px}.sidebar-foot i{width:8px;height:8px;border-radius:50%;background:var(--mint);box-shadow:0 0 12px rgba(89,242,179,.6)}.overlay{display:none}
.main{grid-column:2;min-width:0;padding:28px;background:radial-gradient(circle at 90% 0%,rgba(49,151,118,.08),transparent 32%),var(--bg)}.view{display:none}.view.active{display:block}
.hero{min-height:520px;display:grid;grid-template-columns:1fr 250px;align-items:end;gap:30px;padding:clamp(34px,6vw,72px);border:1px solid var(--line);border-radius:24px;overflow:hidden;background:linear-gradient(90deg,rgba(3,15,12,.95),rgba(3,15,12,.68) 55%,rgba(3,15,12,.25)),linear-gradient(0deg,rgba(3,15,12,.88),transparent),url('images/pcb-background.png') center/cover no-repeat;box-shadow:var(--shadow)}.eyebrow{margin:0 0 10px;color:var(--mint);font:700 12px "Chakra Petch",sans-serif;letter-spacing:.2em}.hero h1,.article-head h1{margin:0;line-height:1.02;letter-spacing:-.045em}.hero h1{font-size:clamp(46px,7vw,86px)}.hero h1 span{color:transparent;background:linear-gradient(90deg,#fff,#8df5cb 60%,#5ddfff);-webkit-background-clip:text;background-clip:text}.lead{max-width:760px;margin:24px 0 0;color:#bdd2ca;font-size:17px}.hero-actions{display:flex;flex-wrap:wrap;gap:12px;margin-top:30px}.primary-btn,.secondary-btn{min-height:46px;padding:0 18px;border-radius:10px;font-weight:700}.primary-btn{background:linear-gradient(135deg,var(--mint),#8affd0);color:#04120e}.secondary-btn{border:1px solid rgba(255,255,255,.13);background:rgba(255,255,255,.04)}.hero-stats{display:grid;gap:12px}.hero-stats div{padding:18px;border:1px solid rgba(255,255,255,.1);border-radius:14px;background:rgba(5,18,14,.58);backdrop-filter:blur(10px)}.hero-stats strong,.hero-stats span{display:block}.hero-stats strong{font:700 25px "Chakra Petch",sans-serif}.hero-stats span{color:var(--muted);font-size:12px}
.panel{margin-top:28px;padding:30px;border:1px solid var(--line);border-radius:20px;background:linear-gradient(145deg,rgba(14,36,30,.82),rgba(7,22,18,.88))}.section-head{display:grid;grid-template-columns:1fr minmax(260px,480px);gap:25px;align-items:end;margin-bottom:24px}.section-head h2,.panel>h2{margin:0;font-size:clamp(28px,4vw,45px);letter-spacing:-.035em}.section-head>p{margin:0;color:var(--muted)}.category-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.category-card{min-height:180px;padding:22px;border:1px solid rgba(255,255,255,.08);border-radius:15px;background:rgba(255,255,255,.025);cursor:pointer;transition:.18s}.category-card:hover{transform:translateY(-3px);border-color:rgba(89,242,179,.25);background:rgba(89,242,179,.04)}.category-card span{color:var(--gold);font:700 12px "Chakra Petch",sans-serif}.category-card h3{margin:22px 0 8px;font-size:20px}.category-card p{margin:0;color:var(--muted);font-size:13px}.workflow-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:1px;margin-top:24px;padding:1px;background:var(--line)}.workflow-grid div{min-height:150px;padding:20px;background:#0b211a}.workflow-grid span{color:var(--mint);font:700 24px "Chakra Petch",sans-serif}.workflow-grid strong,.workflow-grid small{display:block}.workflow-grid strong{margin-top:20px}.workflow-grid small{margin-top:5px;color:var(--muted)}
.topic-view{max-width:1100px;margin:auto}.topic-toolbar{display:flex;align-items:center;justify-content:space-between;gap:20px;margin-bottom:14px}.breadcrumb{color:var(--muted);font-size:13px}.article{border:1px solid var(--line);border-radius:20px;overflow:hidden;background:linear-gradient(145deg,rgba(15,40,33,.94),rgba(7,23,19,.96));box-shadow:var(--shadow)}.article-head{padding:42px 44px 30px;border-bottom:1px solid var(--line);background:linear-gradient(90deg,rgba(7,28,22,.96),rgba(7,28,22,.72)),url('images/pcb-background.png') center/cover no-repeat}.article-head h1{font-size:clamp(34px,5vw,58px)}.topic-lead{max-width:780px;margin:18px 0 0;color:#bdd3ca;font-size:17px}.article-body{padding:38px 44px 48px}.article-body h2{margin:34px 0 12px;font-size:25px}.article-body h2:first-child{margin-top:0}.article-body p,.article-body li{color:#c5d9d1}.article-body code{padding:2px 6px;border:1px solid rgba(89,242,179,.13);border-radius:6px;background:rgba(89,242,179,.06);color:#a0f8d1}.info,.warn{margin:22px 0;padding:18px 20px}.info{border-left:3px solid var(--mint);background:rgba(89,242,179,.055)}.warn{border-left:3px solid var(--gold);background:rgba(239,201,101,.06)}.article-nav{display:flex;justify-content:space-between;gap:12px;padding:20px 44px 30px}.nav-btn{min-width:130px;padding:11px 14px;border:1px solid rgba(255,255,255,.1);border-radius:10px;background:rgba(255,255,255,.03)}.nav-btn:disabled{opacity:.35;cursor:not-allowed}.hidden{display:none!important}
@media(max-width:1100px){.topbar{grid-template-columns:auto 1fr auto}.category-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:860px){:root{--top:112px}.mobile-only{display:grid}.desktop-only{display:none}.topbar{grid-template-columns:1fr auto}.topnav{grid-column:1/-1;order:3;height:42px;margin:0 -18px;padding:0 12px;border-top:1px solid var(--line);justify-content:flex-start}.app-shell{grid-template-columns:1fr}.sidebar{transform:translateX(-103%);transition:.24s;box-shadow:var(--shadow)}.sidebar.open{transform:translateX(0)}.overlay.open{display:block;position:fixed;z-index:70;inset:var(--top) 0 0;background:rgba(0,0,0,.5)}.main{grid-column:1;padding:18px}.hero{grid-template-columns:1fr}.hero-stats{grid-template-columns:repeat(3,1fr)}.section-head{grid-template-columns:1fr}.workflow-grid{grid-template-columns:repeat(2,1fr)}}
@media(max-width:620px){.brand small{display:none}.hero,.panel{padding:22px}.hero{min-height:auto}.hero h1{font-size:46px}.hero-stats,.category-grid,.workflow-grid{grid-template-columns:1fr}.article-head,.article-body,.article-nav{padding-left:24px;padding-right:24px}.topic-toolbar{align-items:flex-start;flex-direction:column}}

/* lesson content */
.lesson-figure{margin:24px 0 30px;padding:14px;border:1px solid var(--line);border-radius:14px;background:rgba(255,255,255,.025)}
.lesson-figure img{display:block;width:100%;height:auto;border-radius:8px}
.lesson-figure figcaption{margin-top:10px;color:var(--muted);font-size:13px;text-align:center}
.interface-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:14px;margin:20px 0}
.interface-card{padding:18px;border:1px solid rgba(255,255,255,.08);border-radius:12px;background:rgba(255,255,255,.025)}
.interface-card strong{display:block;margin-bottom:7px;color:var(--mint)}
.shortcut-table{width:100%;border-collapse:collapse;margin:18px 0}
.shortcut-table th,.shortcut-table td{padding:10px 12px;border-bottom:1px solid var(--line);text-align:left}
.shortcut-table th{color:var(--mint);background:rgba(89,242,179,.04)}
@media(max-width:700px){.interface-grid{grid-template-columns:1fr}}

/* circuit simulation / tutorial links */
.circuit-resource-box{margin:8px 6px 14px;padding:12px;border:1px solid rgba(80,223,255,.16);border-radius:11px;background:linear-gradient(135deg,rgba(80,223,255,.055),rgba(89,242,179,.025))}
.circuit-resource-box strong{display:block;margin-bottom:7px;color:#d9fff0;font-size:13px;letter-spacing:.04em}
.circuit-resource-box a{display:flex;align-items:center;justify-content:space-between;gap:10px;padding:7px 8px;border-radius:8px;color:#9fc7ba;font-size:12px;transition:.18s}
.circuit-resource-box a:hover{color:var(--mint);background:rgba(89,242,179,.07)}
.circuit-resource-box a span{color:var(--cyan);font-size:12px}