:root{
  --bg:#ffffff; --fg:#0d0d0d; --muted:#6b6b6b; --line:#e7e7e9;
  --side:#f7f7f8; --accent:#0d0d0d; --hover:#ececee; --ok:#18a058; --radius:12px;
  font-family:-apple-system,BlinkMacSystemFont,"Segoe UI",Inter,Roboto,Helvetica,Arial,sans-serif;
}
*{box-sizing:border-box;margin:0;padding:0}
html,body{height:100%}
body{background:var(--bg);color:var(--fg);font-size:15px;line-height:1.6;-webkit-font-smoothing:antialiased}
.hidden{display:none !important}

/* GATE */
.gate{position:fixed;inset:0;background:var(--bg);display:flex;align-items:center;justify-content:center;z-index:50}
.gate-card{text-align:center;width:min(360px,90vw)}
.logo{font-size:26px;font-weight:700;letter-spacing:-.5px}
.logo span{color:var(--muted);font-weight:400;margin-left:6px}
.logo.small{font-size:17px}
.gate-sub{color:var(--muted);margin:14px 0 26px}
#pin{width:100%;padding:13px 16px;font-size:18px;text-align:center;letter-spacing:8px;border:1px solid var(--line);border-radius:var(--radius);outline:none;background:#fafafa}
#pin:focus{border-color:#bbb;background:#fff}
#pinBtn{margin-top:14px;width:100%;padding:12px;border:0;border-radius:var(--radius);background:var(--accent);color:#fff;font-size:15px;font-weight:600;cursor:pointer}
#pinBtn:hover{opacity:.85}
.pin-err{color:#d03050;font-size:13px;margin-top:10px;visibility:hidden}
.pin-err.show{visibility:visible}
.gate-note{color:var(--muted);font-size:12.5px;margin-top:16px;line-height:1.5}

/* LAYOUT */
.app{display:flex;height:100vh;overflow:hidden}
.sidebar{width:288px;min-width:288px;background:var(--side);border-right:1px solid var(--line);display:flex;flex-direction:column;transition:margin .2s}
.sidebar.closed{margin-left:-288px}
.brand{display:flex;align-items:center;justify-content:space-between;padding:18px 18px 12px}
.collapse,.menu-toggle{background:none;border:0;font-size:18px;cursor:pointer;color:var(--muted);padding:4px 8px;border-radius:8px}
.collapse:hover,.menu-toggle:hover{background:var(--hover)}
.menu{flex:1;overflow-y:auto;padding:6px 10px 14px}
.pillar{font-size:11px;font-weight:700;text-transform:uppercase;letter-spacing:.8px;color:var(--muted);padding:16px 10px 6px}
.item{display:flex;gap:9px;align-items:flex-start;padding:8px 10px;border-radius:9px;cursor:pointer;color:var(--fg);text-decoration:none;font-size:13.5px;line-height:1.45}
.item:hover{background:var(--hover)}
.item.active{background:#e6e6e9;font-weight:600}
.item .tick{flex:0 0 16px;height:16px;border:1.5px solid #c9c9cd;border-radius:50%;margin-top:2px;position:relative;min-width:16px}
.item.done .tick{background:var(--ok);border-color:var(--ok)}
.item.done .tick::after{content:"";position:absolute;left:4.6px;top:2.2px;width:4px;height:8px;border:solid #fff;border-width:0 2px 2px 0;transform:rotate(45deg)}
.item .t{flex:1}
.item.no-video .tick{border-style:dashed}
.side-foot{padding:14px 18px;border-top:1px solid var(--line);font-size:12px;color:var(--muted)}
.progress-bar{height:5px;background:#e3e3e6;border-radius:99px;margin-top:7px;overflow:hidden}
#progressFill{height:100%;width:0;background:var(--ok);border-radius:99px;transition:width .3s}

.main{flex:1;display:flex;flex-direction:column;overflow:hidden}
.topbar{display:flex;align-items:center;gap:10px;padding:12px 26px;border-bottom:1px solid var(--line);background:rgba(255,255,255,.9);backdrop-filter:blur(6px)}
.crumb{font-size:13px;color:var(--muted)}
.content{flex:1;overflow-y:auto;padding:34px 40px 60px;max-width:980px;width:100%;margin:0 auto}
.content h1{font-size:26px;letter-spacing:-.6px;margin-bottom:6px}
.kicker{font-size:12px;text-transform:uppercase;letter-spacing:1px;color:var(--muted);margin-bottom:14px}
.video{position:relative;width:100%;aspect-ratio:16/9;border-radius:var(--radius);overflow:hidden;background:#000;margin:18px 0 26px;border:1px solid var(--line)}
.video iframe{position:absolute;inset:0;width:100%;height:100%;border:0}
.video .novid{position:absolute;inset:0;display:flex;flex-direction:column;gap:6px;align-items:center;justify-content:center;color:#bbb;background:repeating-linear-gradient(45deg,#111,#111 14px,#161616 14px,#161616 28px)}
.video .novid b{color:#eee;font-size:15px}
.about{font-size:15.5px;color:#242424}
.about p{margin:0 0 15px;line-height:1.7}
.about p:last-child{margin-bottom:0}
.about ul,.about ol{margin:0 0 15px;padding-left:22px}
.about li{margin:0 0 8px;line-height:1.65}
.about ul li{list-style:disc}
.about ol li{list-style:decimal}
.about strong,.about b{font-weight:650;color:#0d0d0d}
.about h2,.about h3,.about h4{margin:22px 0 10px;font-size:17px;letter-spacing:-.2px}
.about blockquote{margin:0 0 15px;padding:10px 16px;border-left:3px solid var(--line);color:var(--muted);background:#fafafa;border-radius:0 8px 8px 0}
.about a{color:#0d6bd6;text-decoration:underline;text-underline-offset:2px;word-break:break-word}
.about img{border-radius:10px;margin:10px 0}
.about code{background:#f2f2f4;padding:1px 6px;border-radius:5px;font-size:13.5px}

/* logo */
.gate-logo{width:min(300px,72vw);height:auto;display:block;margin:0 auto 6px}
.brand-logo{height:34px;width:auto;display:block}

/* top-right nav */
.topnav{margin-left:auto;display:flex;align-items:center;gap:8px}
.topnav-link{font-size:13px;color:var(--muted);text-decoration:none;padding:8px 13px;border-radius:9px;white-space:nowrap}
.topnav-link:hover{background:var(--hover);color:var(--fg)}
.topnav-btn{font-size:13px;border:0;cursor:pointer;padding:8px 15px;border-radius:9px;background:var(--hover);color:var(--fg);font-weight:600;white-space:nowrap}
.topnav-btn.primary{background:var(--accent);color:#fff}
.topnav-btn:hover{opacity:.88}

/* tally CTA */
.tally-wrap{margin:22px 0 4px}
.tally-btn{display:inline-flex;align-items:center;gap:9px;background:var(--accent);color:#fff;border:0;border-radius:12px;padding:15px 26px;font-size:15.5px;font-weight:650;cursor:pointer;box-shadow:0 2px 10px rgba(0,0,0,.12)}
.tally-btn:hover{opacity:.88;transform:translateY(-1px)}
@media (max-width:760px){
  .topnav-link{padding:8px 8px}
  .topnav-btn{padding:8px 10px}
  .crumb{display:none}
}
/* theme toggle */
.gate-top{display:flex;justify-content:flex-end;margin-bottom:2px}
.theme-toggle{border:1px solid var(--line);background:var(--hover);cursor:pointer;font-size:15px;line-height:1;padding:7px 11px;border-radius:99px;color:var(--fg);user-select:none}
.theme-toggle:hover{opacity:.85}

/* dark skin */
body.dark{
  --bg:#212121; --fg:#ececec; --muted:#9b9b9f; --line:#3a3a3c;
  --side:#181818; --hover:#2f2f32; --accent:#ececec;
}
body.dark .topbar{background:rgba(33,33,33,.92)}
body.dark #pin{background:#2a2a2c;color:var(--fg)}
body.dark #pin:focus{background:#2f2f32;border-color:#555}
body.dark #pinBtn{background:var(--accent);color:#141414}
body.dark .topnav-btn.primary,body.dark .tally-btn,body.dark .mark{color:#141414}
body.dark .topnav-btn{color:var(--fg)}
body.dark .item.active{background:#3a3a3c}
body.dark .progress-bar{background:#3a3a3c}
body.dark .about{color:#d6d6d8}
body.dark .about strong,body.dark .about b{color:#f2f2f4}
body.dark .about a{color:#7cb6f5}
body.dark .about blockquote{background:#2a2a2c;color:#b9b9bd}
body.dark .about code{background:#2f2f32}
body.dark .video .novid{background:repeating-linear-gradient(45deg,#161616,#161616 14px,#1c1c1c 14px,#1c1c1c 28px)}
body.dark .video .novid b{color:#d6d6d8}
body.dark .lesson-nav a{color:var(--fg)}
body.dark .pill{background:#2a2a2c;color:#b9b9bd}
body.dark .gate-logo{filter:none}

.pill{display:inline-block;font-size:11.5px;background:var(--side);border:1px solid var(--line);color:var(--muted);border-radius:99px;padding:2px 10px;margin-left:8px;vertical-align:2px}
.mark{margin-top:26px;display:inline-flex;gap:8px;align-items:center;background:var(--accent);color:#fff;border:0;border-radius:10px;padding:10px 18px;font-size:14px;font-weight:600;cursor:pointer}
.mark.done{background:var(--ok)}
.mark:hover{opacity:.88}
.lesson-nav{display:flex;justify-content:space-between;gap:12px;padding:14px 40px;border-top:1px solid var(--line)}
.lesson-nav a{font-size:13.5px;color:var(--fg);text-decoration:none;padding:9px 14px;border:1px solid var(--line);border-radius:10px;max-width:48%}
.lesson-nav a:hover{background:var(--hover)}
.lesson-nav .spacer{flex:1}

.menu-toggle{display:none}
body.sb-closed .menu-toggle{display:block}
@media (max-width:860px){
  .sidebar{position:fixed;z-index:40;height:100%;box-shadow:2px 0 24px rgba(0,0,0,.08)}
  .sidebar.closed{transform:translateX(-100%);margin-left:0}
  .menu-toggle{display:block}
  .content{padding:22px 18px 50px}
  .lesson-nav{padding:12px 18px}
}