:root{
  --void:#07090c; --panel:#0e1116; --panel-raised:#12161c;
  --line:#1e252b; --line-bright:#313a42;

  --signal:#ff4d2e; --phosphor:#ff4d2e; --amber:#ffb020;
  --text:#d7dbde; --text-dim:#7d8891; --text-faint:#4b545c;
  --mono:'IBM Plex Mono',ui-monospace,SFMono-Regular,Menlo,monospace;
  --sans:'IBM Plex Sans',-apple-system,BlinkMacSystemFont,sans-serif;
}

*{box-sizing:border-box}

body{
  font-family:var(--sans);
  background-color:var(--void);
  background-image:radial-gradient(ellipse at 50% -10%,rgba(255,77,46,.06),transparent 62%);
  background-attachment:fixed;
  color:var(--text);
  margin:0;
  line-height:1.6;
  min-height:100vh;
}

.bg-grid{
  position:fixed; inset:0; pointer-events:none; z-index:0; opacity:.45;
  background-image:
    linear-gradient(rgba(49,58,66,.16) 1px,transparent 1px),
    linear-gradient(90deg,rgba(49,58,66,.16) 1px,transparent 1px);
  background-size:64px 64px;
  -webkit-mask-image:radial-gradient(ellipse at 50% 26%,#000 30%,transparent 78%);
  mask-image:radial-gradient(ellipse at 50% 26%,#000 30%,transparent 78%);
}

a{color:inherit}

.topbar{
  display:flex; align-items:center; gap:14px;
  padding:14px 22px;
  background:rgba(7,9,12,.88);
  -webkit-backdrop-filter:blur(8px); backdrop-filter:blur(8px);
  border-bottom:1px solid var(--line);
}
.topbar .title{
  font-family:var(--mono); font-size:1rem; font-weight:600;
  letter-spacing:.16em; text-transform:uppercase; margin:0;
}
.topbar .title .sub{color:var(--text-faint); letter-spacing:.04em; font-weight:400; text-transform:none}
.topbar .spacer{margin-left:auto}

.home-button{
  display:inline-flex; align-items:center; gap:.4em;
  font-family:var(--mono); background:transparent;
  border:1px solid var(--line-bright); color:var(--text-dim);
  font-size:.76rem; font-weight:500; letter-spacing:.03em;
  padding:7px 13px; border-radius:2px; text-decoration:none;
  text-transform:uppercase; cursor:pointer;
  transition:background-color .15s ease,color .15s ease,border-color .15s ease;
}
.home-button:hover{border-color:var(--phosphor); color:var(--phosphor)}

.xp-live{
  display:inline-flex; align-items:center; gap:6px;
  font-family:var(--mono); font-size:.8rem; color:var(--text-dim);
}
.xp-live .chip-icon{color:var(--amber)}
.xp-live b{color:var(--text); font-weight:600}

.account-widget{display:flex; align-items:center; gap:10px; font-family:var(--mono); margin-left:auto}
.account-user{display:flex; align-items:center; gap:8px; font-size:.8rem; color:var(--text-dim)}
.account-user b{color:var(--phosphor)}

.admin-panel{position:fixed; inset:0; z-index:200; display:flex; align-items:center; justify-content:center; padding:20px}
.admin-panel[hidden]{display:none}
.admin-panel-scrim{position:absolute; inset:0; background:rgba(0,0,0,.72); -webkit-backdrop-filter:blur(3px); backdrop-filter:blur(3px)}

.admin-panel-card, .leaderboard-panel-card{
  position:relative; z-index:1; width:100%; max-width:480px;
  background:var(--panel-raised); border:1px solid var(--line-bright);
  border-top:3px solid var(--signal); border-radius:3px;
  padding:22px 24px; box-shadow:0 20px 60px rgba(0,0,0,.5);
  max-height:80vh; overflow-y:auto;
}
.leaderboard-panel-card{max-width:420px}
.admin-panel-head{display:flex; align-items:center; justify-content:space-between; margin-bottom:16px}
.admin-panel-head h2{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; font-size:1.05rem; margin:0; color:var(--text);
}

.admin-panel-close{
  font-family:var(--mono); font-size:.7rem; letter-spacing:.04em; text-transform:uppercase;
  background:transparent; color:var(--text-dim); border:1px solid var(--line-bright); border-radius:2px;
  padding:6px 12px; cursor:pointer; flex-shrink:0;
  transition:background-color .15s ease,color .15s ease,border-color .15s ease;
}
.admin-panel-close:hover{border-color:var(--phosphor); color:var(--phosphor)}
.admin-list{display:flex; flex-direction:column; gap:10px}
.admin-row{
  display:flex; align-items:center; justify-content:space-between; gap:12px;
  border:1px solid var(--line); border-radius:2px; padding:10px 12px;
  background:var(--panel);
}
.admin-row-info{display:flex; flex-direction:column; gap:3px; min-width:0}
.admin-row-name{display:flex; align-items:center; gap:8px; font-size:.9rem; color:var(--text)}
.admin-row-meta{font-size:.72rem; color:var(--text-faint)}
.admin-badge{
  font-family:var(--mono); font-size:.62rem; letter-spacing:.08em; text-transform:uppercase;
  color:var(--amber); border:1px solid var(--amber); border-radius:2px; padding:1px 6px;
}
.admin-row-delete{
  font-family:var(--mono); font-size:.7rem; letter-spacing:.04em; text-transform:uppercase;
  background:transparent; color:#ffb3a5; border:1px solid #ffb3a5; border-radius:2px;
  padding:6px 12px; cursor:pointer; flex-shrink:0;
  transition:background-color .15s ease,color .15s ease;
}
.admin-row-delete:hover:not(:disabled){background:#ffb3a5; color:var(--void)}
.admin-row-delete:disabled{opacity:.5; cursor:not-allowed}
.admin-empty{color:var(--text-dim); font-size:.86rem; margin:0}
.admin-row-error{color:#ffb3a5}
.admin-row-actions{display:flex; align-items:center; gap:6px; flex-shrink:0}
.admin-xp-input{
  width:62px; font-family:var(--mono); font-size:.78rem;
  background:var(--void); color:var(--text);
  border:1px solid var(--line-bright); border-radius:2px;
  padding:5px 7px;
}
.admin-xp-input:focus{outline:none; border-color:var(--phosphor)}
.admin-row-give{
  font-family:var(--mono); font-size:.7rem; letter-spacing:.04em; text-transform:uppercase;
  background:transparent; color:var(--amber); border:1px solid var(--amber); border-radius:2px;
  padding:6px 12px; cursor:pointer; flex-shrink:0;
  transition:background-color .15s ease,color .15s ease;
}
.admin-row-give:hover:not(:disabled){background:var(--amber); color:var(--void)}
.admin-row-give:disabled{opacity:.5; cursor:not-allowed}

@media (max-width:520px){
  .admin-row{flex-wrap:wrap}
  .admin-row-actions{width:100%; justify-content:flex-end}
}

.quit-confirm-card{max-width:380px}
.quit-confirm-card h2{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; font-size:1.05rem; margin:0 0 10px; color:var(--text);
}
.quit-confirm-card p{color:var(--text-dim); line-height:1.5; margin:0 0 20px}
.quit-confirm-actions{display:flex; gap:10px}
.quit-confirm-actions .btn{flex:1; text-align:center}

.login-page{display:flex; justify-content:center; padding-top:60px}
.login-card{
  width:100%; max-width:420px;
  background:var(--panel-raised); border:1px solid var(--line-bright);
  border-top:3px solid var(--signal); border-radius:3px;
  padding:32px 30px;
}
.login-card h1{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.08em; font-size:1.6rem; margin:8px 0 14px; color:var(--text);
}
.login-card .tagline{color:var(--text-dim); line-height:1.55; margin:0 0 24px}
.login-tabs{display:flex; gap:8px; margin-bottom:18px}
.login-tab{
  flex:1; font-family:var(--mono); font-size:.82rem; letter-spacing:.06em;
  text-transform:uppercase; padding:10px; cursor:pointer;
  background:var(--panel); color:var(--text-dim);
  border:1px solid var(--line-bright); border-radius:2px;
  transition:border-color .15s ease,color .15s ease;
}
.login-tab.active{color:var(--signal); border-color:var(--signal)}
.login-tab:hover{color:var(--text)}
#login-form-slot form{display:flex; flex-direction:column; gap:12px}
#login-form-slot input{
  font-family:var(--mono); font-size:.92rem;
  background:var(--void); color:var(--text);
  border:1px solid var(--line-bright); border-radius:2px;
  padding:11px 14px;
}
#login-form-slot input:focus{outline:none; border-color:var(--signal)}
#login-form-slot .btn.primary{width:100%; margin-left:0; margin-top:4px}
.login-skip{
  display:block; text-align:center; margin-top:22px;
  font-family:var(--mono); font-size:.78rem; color:var(--text-faint);
  text-decoration:none;
}
.login-skip:hover{color:var(--text-dim)}
.login-privacy{
  display:block; text-align:center; margin-top:10px;
  font-family:var(--mono); font-size:.7rem; color:var(--text-faint);
  line-height:1.5;
}

@media (max-width:500px){
  .login-page{padding-top:20px}
  .login-card{padding:24px 20px}
}

.welcome-banner{
  display:flex; flex-wrap:wrap; align-items:center; gap:24px;
  justify-content:space-between;
  border:1px solid var(--line-bright); border-left:3px solid var(--phosphor);
  background:linear-gradient(135deg, var(--panel-raised) 0%, var(--panel) 100%);
  border-radius:3px; padding:24px 28px; margin:0 0 26px;
}
.welcome-banner[hidden]{display:none}
.welcome-copy{flex:1; min-width:260px}
.welcome-copy .eyebrow{margin-bottom:8px}
.welcome-copy h2{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; font-size:1.3rem; margin:0 0 10px; color:var(--text);
}
.welcome-copy p{color:var(--text-dim); margin:0; max-width:52ch; line-height:1.55}
.welcome-actions{display:flex; flex-direction:column; gap:10px; min-width:200px}
.welcome-actions .btn{width:100%; text-align:center}

.auth-error{color:#ffb3a5; font-size:.8rem; margin:6px 0 0}

.leaderboard-panel{position:fixed; inset:0; z-index:200; display:flex; align-items:center; justify-content:center; padding:20px}
.leaderboard-panel[hidden]{display:none}
.leaderboard-panel-scrim{position:absolute; inset:0; background:rgba(0,0,0,.72); -webkit-backdrop-filter:blur(3px); backdrop-filter:blur(3px)}
#leaderboard-body ol{list-style:none; margin:0; padding:0; display:flex; flex-direction:column; gap:6px}
#leaderboard-body li{
  display:flex; align-items:center; gap:10px;
  font-family:var(--mono); font-size:.86rem;
  padding:6px 4px; border-bottom:1px solid var(--line);
}
#leaderboard-body li:last-child{border-bottom:none}
#leaderboard-body .lb-rank{color:var(--text-faint); width:2ch; text-align:right}
#leaderboard-body .lb-name{flex:1; color:var(--text); text-decoration:none}
#leaderboard-body a.lb-name:hover{color:var(--phosphor); text-decoration:underline}
#leaderboard-body .lb-name.me{color:var(--phosphor)}
#leaderboard-body .lb-xp{color:var(--amber); font-weight:600}
#leaderboard-body .lb-empty{color:var(--text-faint); font-size:.84rem}

.admin-section-head{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; font-size:.9rem; margin:22px 0 12px; color:var(--text);
  padding-top:16px; border-top:1px solid var(--line);
}
.admin-row-message{
  margin:2px 0; color:var(--text-dim); font-size:.8rem; line-height:1.5;
  white-space:pre-wrap; word-break:break-word;
}

.badge-grid{display:grid; grid-template-columns:repeat(auto-fill,minmax(210px,1fr)); gap:10px}
.badge-card{
  display:flex; align-items:center; gap:12px;
  border:1px solid var(--line); border-radius:2px; padding:12px 14px;
  background:var(--panel);
}
.badge-card.locked{opacity:.38}
.badge-icon{font-size:1.4rem; flex-shrink:0; line-height:1}
.badge-copy{display:flex; flex-direction:column; gap:2px; min-width:0}
.badge-copy b{font-size:.84rem; color:var(--text)}
.badge-copy span{font-size:.72rem; color:var(--text-faint)}

.profile-stats{margin-bottom:28px}
.profile-badges-title{
  font-family:var(--mono); font-weight:700; text-transform:uppercase;
  letter-spacing:.06em; font-size:1rem; margin:0 0 14px; color:var(--text);
}

.wrap{position:relative; z-index:1; max-width:860px; margin:0 auto; padding:40px 22px 90px}

.hero{margin-bottom:30px}
.eyebrow{
  font-family:var(--mono); font-size:.7rem; letter-spacing:.32em;
  text-transform:uppercase; color:var(--text-faint); margin:0 0 12px;
}
.eyebrow::before{content:"// "; color:var(--phosphor)}
.hero h1{
  font-family:var(--mono); font-weight:700;
  font-size:clamp(2rem,7vw,3.2rem); line-height:1;
  letter-spacing:.1em; text-transform:uppercase; margin:0 0 10px;
}
.hero .tagline{color:var(--text-dim); margin:0; max-width:56ch}

.stats{
  display:flex; flex-wrap:wrap; gap:12px; align-items:center;
  margin:26px 0 22px;
}
.stat-chip{
  display:flex; align-items:baseline; gap:8px;
  font-family:var(--mono);
  border:1px solid var(--line); background:var(--panel);
  border-radius:2px; padding:10px 14px;
}
.stat-chip b{font-size:1.25rem; font-weight:600; color:var(--text)}
.stat-chip .chip-icon{font-size:.9rem; color:var(--text-faint)}
.stat-chip .chip-label{
  font-size:.64rem; letter-spacing:.16em; text-transform:uppercase; color:var(--text-faint);
}
.stat-chip.streak.alight .chip-icon{color:var(--signal)}
.stat-chip.streak.alight b{color:var(--signal)}
.stat-chip.xp .chip-icon{color:var(--amber)}

.goal{display:flex; align-items:center; gap:10px; margin-left:auto}
.goal-ring{width:48px; height:48px; transform:rotate(-90deg)}
.ring-track{fill:none; stroke:var(--line); stroke-width:5}
.ring-fill{
  fill:none; stroke:var(--phosphor); stroke-width:5; stroke-linecap:round;
  transition:stroke-dashoffset .5s ease;
}
.goal-text{font-family:var(--mono); line-height:1.3}
.goal-text b{display:block; font-size:.9rem; font-weight:600}
.goal-text span{font-size:.62rem; letter-spacing:.14em; text-transform:uppercase; color:var(--text-faint)}
.goal-edit-btn{font-size:.62rem; letter-spacing:.14em; text-transform:uppercase; margin-left:4px}
.goal-edit-form{display:flex; align-items:center; gap:8px}
.goal-edit-form input{
  width:64px; font-family:var(--mono); font-size:.86rem;
  background:var(--void); color:var(--text);
  border:1px solid var(--line-bright); border-radius:2px;
  padding:4px 6px;
}
.goal-edit-form input:focus{outline:none; border-color:var(--phosphor)}
.goal-edit-form .linkish{font-size:.68rem}

.courses{display:flex; flex-wrap:wrap; gap:8px; margin:26px 0 10px}
.course-tab{
  display:inline-flex; align-items:center; gap:9px;
  border:1px solid var(--line); background:var(--panel);
  border-radius:2px; padding:9px 14px; text-decoration:none; color:var(--text-dim);
  transition:border-color .16s ease,color .16s ease,background-color .16s ease;
}
.course-tab:hover{border-color:var(--line-bright); color:var(--text); background:var(--panel-raised)}
.course-tab .course-badge{
  font-family:var(--mono); font-size:.66rem; font-weight:600;
  letter-spacing:.08em; text-transform:uppercase; color:var(--text-faint);
  border:1px solid var(--line-bright); border-radius:2px;
  padding:2px 6px; min-width:32px; text-align:center;
}
.course-tab .course-name{font-family:var(--mono); font-size:.84rem; letter-spacing:.04em}
.course-tab.active{border-color:var(--phosphor); color:var(--text); background:var(--panel-raised)}
.course-tab.active .course-badge{border-color:var(--phosphor); color:var(--phosphor)}

.course-blurb{
  color:var(--text-dim); font-size:.9rem; margin:0 0 18px; max-width:62ch;
}

.practice-card{
  display:flex; align-items:center; gap:14px;
  border:1px solid var(--line); background:var(--panel);
  border-radius:2px; padding:16px 18px; margin-bottom:34px;
  text-decoration:none; transition:border-color .18s ease,background-color .18s ease;
}
.practice-card:hover{border-color:var(--line-bright); background:var(--panel-raised)}
.practice-card.due{border-color:rgba(255,176,32,.5)}
.practice-card.due .practice-icon{color:var(--amber)}
.practice-icon{font-size:1.3rem; color:var(--text-faint)}
.practice-copy{display:flex; flex-direction:column; line-height:1.35}
.practice-copy b{font-family:var(--mono); letter-spacing:.06em; text-transform:uppercase; font-size:.86rem}
.practice-copy span{font-size:.86rem; color:var(--text-dim)}
.practice-go{
  margin-left:auto; font-family:var(--mono); font-size:.72rem;
  letter-spacing:.14em; text-transform:uppercase; color:var(--phosphor);
}

.unit{margin-bottom:44px}
.unit-head{margin-bottom:22px; padding-bottom:14px; border-bottom:1px solid var(--line)}
.unit-index{
  font-family:var(--mono); font-size:.66rem; letter-spacing:.22em;
  text-transform:uppercase; color:var(--phosphor);
}
.unit-head h2{
  font-family:var(--mono); font-size:1.15rem; font-weight:600;
  letter-spacing:.05em; margin:6px 0 6px;
}
.unit-head p{margin:0; color:var(--text-dim); font-size:.92rem; max-width:60ch}
.unit.upcoming{opacity:.5}
.upcoming-note{
  font-family:var(--mono); font-size:.74rem; letter-spacing:.14em;
  text-transform:uppercase; color:var(--text-faint); margin:0;
}

.track{display:flex; flex-direction:column; gap:14px}

.node{
  --lean:0;
  display:flex; align-items:center; gap:16px;
  border:1px solid var(--line); background:var(--panel);
  border-radius:2px; padding:16px 18px;
  text-decoration:none; color:inherit;
  transform:translateX(calc(var(--lean) * 22px));
  transition:border-color .18s ease,transform .18s ease,background-color .18s ease;
}
.node.available{border-color:var(--line-bright)}
.node.available:hover,.node.complete:hover,.node.due:hover{
  border-color:var(--phosphor); background:var(--panel-raised);
  transform:translateX(calc(var(--lean) * 22px)) translateY(-1px);
}
.node.locked{opacity:.42; cursor:not-allowed}
.node.complete{border-color:rgba(53,214,124,.34)}
.node.due{border-color:rgba(255,176,32,.44)}

.node-badge{
  flex:none; width:38px; height:38px; border-radius:50%;
  display:grid; place-items:center;
  border:1px solid var(--line-bright); background:var(--void);
  font-size:.9rem;
}
.node.available .node-badge{border-color:var(--phosphor); color:var(--phosphor)}
.node.complete .node-badge{border-color:var(--phosphor); color:var(--phosphor); background:rgba(53,214,124,.1)}
.node.due .node-badge{border-color:var(--amber); color:var(--amber)}

.node-body{display:flex; flex-direction:column; gap:3px; min-width:0}
.node-body b{font-family:var(--mono); font-size:.95rem; letter-spacing:.03em; font-weight:600}
.node-blurb{font-size:.85rem; color:var(--text-dim)}

.pips{display:flex; gap:4px; margin-top:6px}
.pip{width:14px; height:3px; background:var(--line-bright); border-radius:1px; display:block}
.pip.on{background:var(--phosphor)}

.load-error{border:1px solid var(--signal); padding:20px; border-radius:2px; background:var(--panel)}
.load-error h2{font-family:var(--mono); margin:0 0 8px; font-size:1rem}
.load-error p{margin:0; color:var(--text-dim)}

.page-foot{
  margin-top:50px; padding-top:18px; border-top:1px solid var(--line);
  display:flex; align-items:center; gap:14px;
  font-family:var(--mono); font-size:.72rem; color:var(--text-faint);
}
.page-foot span{flex:1 1 auto; min-width:0}
.page-foot .note-error{color:var(--signal)}
.linkish{
  background:none; border:none; color:var(--text-faint); cursor:pointer;
  font-family:var(--mono); font-size:.72rem; text-decoration:underline;
  text-underline-offset:3px; padding:0; flex:none;
}
.linkish:hover{color:var(--phosphor)}
.linkish.danger:hover{color:var(--signal)}

.field-label{
  display:block; font-family:var(--mono); font-size:.64rem;
  letter-spacing:.18em; text-transform:uppercase;
  color:var(--text-faint); margin:0 0 8px;
}
.field-label[hidden]{display:none}
.run-status{
  font-family:var(--mono); font-size:.7rem; letter-spacing:.12em;
  text-transform:uppercase; color:var(--text-faint); align-self:center;
}
.wrap textarea.editor{margin-bottom:16px}
.playground-head{margin-bottom:18px}
.picker{
  font-family:var(--mono); font-size:.86rem;
  background:var(--panel); color:var(--text);
  border:1px solid var(--line-bright); border-radius:2px;
  padding:9px 12px; min-width:190px;
}
.picker:focus{outline:none; border-color:var(--phosphor)}
.wrap .preview-frame{height:340px; margin-bottom:16px}
.wrap .output{min-height:80px}

.preview{margin:0 0 16px}
.preview-label{
  font-family:var(--mono); font-size:.64rem; letter-spacing:.18em;
  text-transform:uppercase; color:var(--text-faint); margin-bottom:8px;
}
.preview-frame{
  width:100%; height:260px; border:1px solid var(--line-bright);
  border-left:2px solid var(--amber); border-radius:2px;
  background:#fff; display:block;
}
.preview-frame[hidden]{display:none}
.hint.scaffold pre.code{margin:12px 0 0}

.tok-var{color:#c792ea}

.hint.solution{border-color:var(--line-bright)}
.hint.solution summary{color:var(--amber)}
.hint.solution pre.code{margin:12px 0 0}

.progress-rail{height:3px; background:var(--line); position:sticky; top:59px; z-index:5}
.progress-fill{height:100%; width:0; background:var(--phosphor); transition:width .35s ease}

.lesson-wrap{max-width:760px; margin:0 auto; padding:34px 22px 150px; position:relative; z-index:1}

.ex-title{
  font-family:var(--mono); font-size:1.3rem; letter-spacing:.04em;
  margin:0 0 14px; font-weight:600;
}
.prompt{font-size:1.06rem; margin:0 0 18px; color:var(--text)}
.teach-body p{color:var(--text-dim); margin:0 0 14px}
.teach-body code,.prompt code{
  font-family:var(--mono); font-size:.88em;
  background:var(--panel-raised); border:1px solid var(--line);
  padding:1px 5px; border-radius:2px; color:var(--phosphor);
}

pre.code{
  font-family:var(--mono); font-size:.9rem; line-height:1.65;
  background:var(--panel); border:1px solid var(--line);
  border-left:2px solid var(--line-bright);
  border-radius:2px; padding:14px 16px; margin:0 0 16px;
  overflow-x:auto; white-space:pre; tab-size:4;
}
.tok-key{color:var(--signal)}
.tok-string{color:var(--phosphor)}
.tok-comment{color:var(--text-faint); font-style:italic}
.tok-builtin{color:var(--amber)}
.tok-num{color:#79c0ff}

.code-demo{margin-bottom:8px}
.editor-actions{display:flex; gap:10px; margin-bottom:14px}

.output{
  font-family:var(--mono); font-size:.86rem; line-height:1.6;
  background:var(--void); border:1px solid var(--line);
  border-left:2px solid var(--phosphor);
  padding:12px 14px; margin:0 0 16px; border-radius:2px;
  white-space:pre-wrap; word-break:break-word; color:var(--text-dim);
}
.output.busy{border-left-color:var(--amber); color:var(--text-faint)}
.output.error{border-left-color:var(--signal); color:#ffb3a5}

.choices{display:flex; flex-direction:column; gap:10px}
.choice{
  display:flex; align-items:center; gap:14px; text-align:left;
  background:var(--panel); border:1px solid var(--line); color:var(--text);
  border-radius:2px; padding:14px 16px; cursor:pointer;
  font-family:var(--sans); font-size:.98rem; line-height:1.5;
  transition:border-color .15s ease,background-color .15s ease;
}
.choice:hover:not(:disabled){border-color:var(--line-bright); background:var(--panel-raised)}
.choice:disabled{cursor:default}
.choice-key{
  flex:none; width:26px; height:26px; border-radius:2px;
  display:grid; place-items:center;
  font-family:var(--mono); font-size:.76rem;
  border:1px solid var(--line-bright); color:var(--text-faint);
}
.choice-text{white-space:pre-wrap; font-family:var(--mono); font-size:.9rem}
.choice.picked{border-color:var(--text-dim)}
.choice.right{border-color:var(--phosphor); background:rgba(53,214,124,.08)}
.choice.right .choice-key{border-color:var(--phosphor); color:var(--phosphor)}
.choice.wrong{border-color:var(--signal); background:rgba(255,77,46,.07)}
.choice.wrong .choice-key{border-color:var(--signal); color:var(--signal)}

pre.code.fill{white-space:pre-wrap}
input.blank{
  font-family:var(--mono); font-size:.88rem;
  background:var(--void); color:var(--amber);
  border:none; border-bottom:2px solid var(--amber);
  padding:1px 6px; margin:0 2px; min-width:5ch;
}
input.blank:focus{outline:none; background:rgba(255,176,32,.08)}
input.blank.right{color:var(--phosphor); border-bottom-color:var(--phosphor)}
input.blank.wrong{color:var(--signal); border-bottom-color:var(--signal)}

.parsons{display:flex; flex-direction:column; gap:16px}
.parsons-label{
  font-family:var(--mono); font-size:.64rem; letter-spacing:.18em;
  text-transform:uppercase; color:var(--text-faint); margin-bottom:8px;
}
.parsons-solution{
  list-style:none; margin:0; padding:12px; min-height:72px;
  border:1px dashed var(--line-bright); border-radius:2px; background:var(--panel);
  display:flex; flex-direction:column; gap:6px;
}
.parsons-empty{color:var(--text-faint); font-size:.86rem; font-style:italic}
.parsons-line{
  display:flex; align-items:center; gap:10px;
  background:var(--panel-raised); border:1px solid var(--line);
  border-radius:2px; padding:8px 10px;
}
.parsons-line code{font-family:var(--mono); font-size:.88rem; white-space:pre; flex:1; overflow-x:auto}
.parsons-line.right{border-color:rgba(53,214,124,.5)}
.parsons-line.wrong{border-color:rgba(255,77,46,.5)}
.parsons-controls{display:flex; gap:4px; flex:none}
.micro{
  width:24px; height:24px; display:grid; place-items:center;
  background:var(--void); border:1px solid var(--line-bright);
  color:var(--text-dim); border-radius:2px; cursor:pointer; font-size:.8rem;
}
.micro:hover:not(:disabled){color:var(--phosphor); border-color:var(--phosphor)}
.micro:disabled{opacity:.3; cursor:default}
.parsons-bank{display:flex; flex-direction:column; gap:6px}
.parsons-option{
  text-align:left; background:var(--panel); border:1px solid var(--line);
  border-radius:2px; padding:8px 10px; cursor:pointer; color:var(--text);
}
.parsons-option:hover:not(:disabled){border-color:var(--phosphor)}
.parsons-option code{font-family:var(--mono); font-size:.88rem; white-space:pre}
.answer-label{
  font-family:var(--mono); font-size:.66rem; letter-spacing:.18em;
  text-transform:uppercase; color:var(--text-faint); margin:16px 0 8px;
}

textarea.editor{
  width:100%; font-family:var(--mono); font-size:.9rem; line-height:1.65;
  background:var(--panel); color:var(--text);
  border:1px solid var(--line-bright); border-left:2px solid var(--phosphor);
  border-radius:2px; padding:14px 16px; margin-bottom:12px;
  resize:vertical; tab-size:4;
}
textarea.editor:focus{outline:none; border-color:var(--phosphor)}

.term-shell{
  font-family:var(--mono); font-size:.86rem; line-height:1.6;
  background:var(--void); color:var(--text-dim);
  border:1px solid var(--line-bright); border-left:2px solid var(--phosphor);
  border-radius:2px; padding:12px 14px; margin-bottom:12px; cursor:text;
}
.term-modes{display:flex; gap:6px; margin-bottom:10px}
.term-mode{
  font-family:var(--mono); font-size:.66rem; letter-spacing:.06em;
  background:transparent; color:var(--text-faint);
  border:1px solid var(--line); border-radius:2px;
  padding:4px 9px; cursor:pointer; transition:border-color .15s ease,color .15s ease;
}
.term-mode:hover{color:var(--text-dim); border-color:var(--line-bright)}
.term-mode.active{color:var(--phosphor); border-color:var(--phosphor)}
.term-history{white-space:pre-wrap; word-break:break-word; max-height:280px; overflow-y:auto}
.term-history:not(:empty){margin-bottom:8px}
.term-cmd{color:var(--text)}
.term-print{color:var(--text-dim)}
.term-err{color:#ffb3a5}
.term-input-row{display:flex; align-items:center; gap:8px}
.term-prompt{color:var(--phosphor); font-weight:600}
.term-input{
  flex:1; font-family:var(--mono); font-size:.86rem;
  background:transparent; color:var(--text); border:none; outline:none;
}

.hint{
  border:1px solid var(--line); background:var(--panel);
  border-radius:2px; padding:10px 14px; margin-bottom:14px;
}
.hint summary{
  cursor:pointer; font-family:var(--mono); font-size:.76rem;
  letter-spacing:.08em; color:var(--text-dim);
}
.hint p{margin:10px 0 0; color:var(--text-dim); font-size:.9rem}

.test-list{list-style:none; margin:0 0 10px; padding:0; display:flex; flex-direction:column; gap:6px}
.test-list[hidden]{display:none}
.test{
  display:flex; align-items:flex-start; gap:10px;
  font-family:var(--mono); font-size:.84rem;
  border:1px solid var(--line); border-radius:2px; padding:8px 12px;
  background:var(--panel);
}
.test-mark{flex:none}
.test.pass{border-color:rgba(53,214,124,.35)}
.test.pass .test-mark{color:var(--phosphor)}
.test.fail{border-color:rgba(255,77,46,.35)}
.test.fail .test-mark{color:var(--signal)}

.action-bar{
  position:fixed; left:0; right:0; bottom:0; z-index:7;
  background:rgba(7,9,12,.94);
  -webkit-backdrop-filter:blur(10px); backdrop-filter:blur(10px);
  border-top:1px solid var(--line);
}
.action-inner{
  max-width:760px; margin:0 auto; padding:14px 22px;
  display:flex; align-items:center; gap:16px;
}

.feedback{
  max-width:760px; margin:0 auto; padding:14px 22px 0;
  border-top:2px solid transparent;
}
.feedback strong{font-family:var(--mono); font-size:.94rem; letter-spacing:.03em; display:block}
.feedback p{margin:6px 0 0; font-size:.9rem; color:var(--text-dim)}
.feedback.good strong{color:var(--phosphor)}
.feedback.bad strong{color:var(--signal)}

.btn{
  font-family:var(--mono); font-size:.8rem; font-weight:600;
  letter-spacing:.12em; text-transform:uppercase;
  padding:12px 26px; border-radius:2px; cursor:pointer;
  text-decoration:none; display:inline-block; text-align:center;
  border:1px solid var(--phosphor); background:transparent; color:var(--phosphor);
  transition:background-color .15s ease,color .15s ease,opacity .15s ease;
}
.btn:hover:not(:disabled){background:var(--phosphor); color:var(--void)}
.btn:disabled{opacity:.32; cursor:not-allowed}
.btn[hidden]{display:none}
.btn.primary{margin-left:auto; min-width:170px}
.btn.ghost{
  border-color:var(--line-bright); color:var(--text-dim);
  padding:8px 16px; letter-spacing:.08em;
}
.btn.ghost:hover:not(:disabled){background:transparent; border-color:var(--phosphor); color:var(--phosphor)}

.summary{text-align:center; padding:40px 0 20px}
.summary-mark{font-size:3rem; color:var(--phosphor); line-height:1}
.summary h2{font-family:var(--mono); letter-spacing:.06em; margin:14px 0 26px; font-size:1.4rem}
.summary-stats{
  display:flex; justify-content:center; flex-wrap:wrap;
  border:1px solid var(--line); border-radius:2px;
  background:var(--panel); max-width:460px; margin:0 auto 22px; font-family:var(--mono);
}
.sstat{flex:1 1 0; min-width:110px; padding:14px 10px}
.sstat + .sstat{border-left:1px solid var(--line)}
.sstat b{display:block; font-size:1.4rem; font-weight:600; color:var(--phosphor)}
.sstat span{
  display:block; font-size:.62rem; letter-spacing:.16em;
  text-transform:uppercase; color:var(--text-faint); margin-top:4px;
}
.summary-note{color:var(--text-dim); max-width:48ch; margin:0 auto 28px}
.summary-actions{display:flex; justify-content:center; gap:12px}
.summary-actions .btn.primary{margin-left:0}

@media (max-width:620px){
  .node{transform:none}
  .node.available:hover,.node.complete:hover,.node.due:hover{transform:translateY(-1px)}
  .goal{margin-left:0}
  .action-inner{padding:12px 16px}
  .btn.primary{min-width:130px}

  .wrap{padding:24px 16px 80px}
  .topbar{flex-wrap:wrap; padding:12px 16px; gap:10px}
  .topbar .title{font-size:.86rem; letter-spacing:.1em}
  .account-user{flex-wrap:wrap; justify-content:flex-end}
  .account-user span{display:none}

  .hero{margin-bottom:22px}
  .hero .tagline{font-size:.92rem}

  .welcome-banner{flex-direction:column; align-items:stretch; padding:18px 18px 20px; gap:16px}
  .welcome-actions{min-width:0}

  .courses{gap:6px}
  .course-tab{padding:9px 12px; font-size:.8rem}

  .stats{gap:8px}
  .stat-chip{padding:8px 11px}
  .goal{width:100%; margin-left:0; justify-content:flex-start}

  .leaderboard-panel-card{padding:16px}
  #leaderboard-body li{font-size:.8rem; gap:8px; flex-wrap:wrap}

  textarea.editor{font-size:.82rem; padding:12px 14px}
  .term-shell{font-size:.8rem; padding:10px 12px}
  .term-history{max-height:200px}
  .term-modes{flex-wrap:wrap}

  .choices{gap:8px}
  .choice{padding:12px 14px; font-size:.92rem}

  .editor-actions{flex-wrap:wrap; gap:8px}
  .action-inner .btn.primary{width:100%; margin-left:0}
}

@media (max-width:400px){
  .topbar .title .sub{display:none}
  .hero h1{font-size:1.7rem}
  .summary-actions{flex-direction:column}
  .summary-actions .btn{width:100%}
}