/* ── DSA Prep — terminal theme ───────────────────────────────────────────── */
:root {
  --bg: #0a0e0a; --bg2: #0d120d; --bg3: #131a13; --line: #1f2a1f; --line2: #2c3a2c;
  --fg: #b8f5b8; --fg-dim: #5f8a5f; --fg-mute: #3f5c3f;
  --accent: #39ff6a; --accent-dim: #1f8f3f;
  --amber: #ffb454; --cyan: #56e0e0; --magenta: #e06ad0;
  --bad: #ff5f5f; --good: #39ff6a; --warn: #ffb454;
  --mono: ui-monospace, "SF Mono", SFMono-Regular, Menlo, Consolas, "DejaVu Sans Mono", "Liberation Mono", monospace;
  --glow: 0 0 2px rgba(57,255,106,.35);
}
body.light {
  --bg: #f3f3ec; --bg2: #eaeae0; --bg3: #e0e0d4; --line: #cdcdbf; --line2: #b9b9a9;
  --fg: #1c2b1c; --fg-dim: #4a5d4a; --fg-mute: #7a8a7a;
  --accent: #0a7a2a; --accent-dim: #0a7a2a;
  --amber: #9a5b00; --cyan: #0a6a6a; --magenta: #8a2a7a;
  --bad: #b30000; --good: #0a7a2a; --warn: #9a5b00;
  --glow: none;
}
* { box-sizing: border-box; }
html, body { height: 100%; margin: 0; }
body {
  background: var(--bg); color: var(--fg);
  font: 15px/1.55 var(--mono);
  -webkit-font-smoothing: antialiased;
}
body:not(.light)::after {     /* faint scanlines */
  content: ""; position: fixed; inset: 0; pointer-events: none; z-index: 9999;
  background: repeating-linear-gradient(0deg, rgba(0,0,0,.16) 0, rgba(0,0,0,.16) 1px, transparent 1px, transparent 3px);
  opacity: .35; mix-blend-mode: multiply;
}
::selection { background: var(--accent); color: #000; }
::-webkit-scrollbar { width: 9px; height: 9px; }
::-webkit-scrollbar-thumb { background: var(--line2); }
::-webkit-scrollbar-track { background: transparent; }
a { color: var(--cyan); text-decoration: none; }
a:hover { text-decoration: underline; }

.admin-gate {
  position: fixed; inset: 0; z-index: 10000; display: grid; place-items: center;
  background: rgba(10, 14, 10, .92); padding: 18px;
}
.admin-gate[hidden] { display: none; }
.admin-card {
  width: min(360px, 100%); border: 1px solid var(--line2); background: var(--bg2);
  padding: 16px; box-shadow: 0 0 0 1px var(--bg), var(--glow);
}
.admin-title { color: var(--accent); font-weight: 700; margin-bottom: 12px; }
.admin-card label { display: block; color: var(--fg-dim); font-size: 12.5px; margin: 10px 0 3px; text-transform: uppercase; }
.admin-card input {
  width: 100%; background: var(--bg); color: var(--fg); border: 1px solid var(--line2);
  padding: 7px 8px; font: inherit; outline: none;
}
.admin-card input:focus { border-color: var(--accent-dim); box-shadow: var(--glow); }
.admin-card button {
  width: 100%; margin-top: 14px; background: var(--bg3); color: var(--accent);
  border: 1px solid var(--accent-dim); padding: 7px 8px; font: inherit; cursor: pointer;
}
.admin-card button:hover { background: var(--accent); color: #000; }
.admin-error { min-height: 18px; margin-top: 9px; color: var(--bad); font-size: 12.5px; }

#app { display: flex; height: 100vh; overflow: hidden; }

/* ── sidebar ─────────────────────────────────────────────────────────────── */
#sidebar { width: 360px; min-width: 240px; max-width: 540px; background: var(--bg2); border-right: 1px solid var(--line2); display: flex; flex-direction: column; resize: horizontal; overflow: hidden; }
.sb-head { padding: 10px 12px; border-bottom: 1px solid var(--line2); }
.sb-head .title { font-weight: 700; color: var(--accent); text-shadow: var(--glow); letter-spacing: .02em; }
.sb-head .title::before { content: "┌─ "; color: var(--fg-mute); }
.sb-head .title::after { content: " ─┐"; color: var(--fg-mute); }
.sb-head .sub { color: var(--fg-dim); font-size: 12.5px; margin: 3px 0 8px; }
.sb-head .sub::before { content: "# "; color: var(--fg-mute); }
#search { width: 100%; padding: 6px 8px; background: var(--bg); border: 1px solid var(--line2); color: var(--fg); font: inherit; outline: none; }
#search:focus { border-color: var(--accent-dim); box-shadow: var(--glow); }
#search::placeholder { color: var(--fg-mute); }

#tree { overflow-y: auto; flex: 1; padding: 6px 2px 30px; }
#tree details { margin: 0; }
#tree summary { cursor: pointer; padding: 3px 8px; list-style: none; user-select: none; white-space: nowrap; overflow: hidden; text-overflow: ellipsis; }
#tree summary::-webkit-details-marker { display: none; }
#tree summary::before { color: var(--fg-mute); }
#tree details > summary::before { content: "[+] "; }
#tree details[open] > summary::before { content: "[-] "; }
#tree summary:hover { background: var(--bg3); color: var(--accent); }
#tree .section > summary { color: var(--amber); font-weight: 700; }
#tree .path > summary { color: var(--fg); padding-left: 18px; }
#tree .module > summary { color: var(--fg-dim); padding-left: 34px; font-size: 14px; }
#tree .module > summary::before { content: "├ "; }
#tree details[open] > .module > summary::before { content: "├ "; }
#tree .count { color: var(--fg-mute); font-weight: 400; font-size: 12.5px; }
#tree .count::before { content: "("; } #tree .count::after { content: ")"; }
#tree a.prob { display: block; padding: 2px 8px 2px 32px; color: var(--fg-dim); white-space: nowrap; overflow: hidden; text-overflow: ellipsis; font-size: 14px; }
#tree a.prob .st { display: inline-block; width: 2em; margin-right: 3px; color: var(--fg-mute); cursor: pointer; text-align: left; }
#tree a.prob.st-none .st::before { content: "[ ]"; }
#tree a.prob.st-attempted .st::before { content: "[~]"; }
#tree a.prob.st-solved .st::before { content: "[x]"; }
#tree a.prob.st-attempted { color: var(--fg-dim); }
#tree a.prob.st-attempted .st { color: var(--amber); }
#tree a.prob.st-solved { color: var(--fg); }
#tree a.prob.st-solved .st { color: var(--good); }
#tree a.prob .st:hover { color: var(--accent); text-shadow: var(--glow); }
#tree a.prob:hover { background: var(--bg3); color: var(--fg); text-decoration: none; }
#tree a.prob.active { background: var(--accent); color: #000; font-weight: 700; }
#tree a.prob.active .st, #tree a.prob.active .diff { color: #000; }
#tree a.prob.lesson { color: var(--fg-mute); }
#tree a.prob.lesson.st-none { color: var(--fg-mute); }
#tree a.prob.lesson::after { content: " ~mcq"; font-size: 11.5px; opacity: .7; }
#tree a.prob .diff { float: right; color: var(--magenta); font-size: 12.5px; }
.sb-foot .reset-prog { background: transparent; border: 1px solid var(--line2); color: var(--fg-dim); font: 12.5px var(--mono); padding: 1px 6px; margin-left: 8px; cursor: pointer; }
.sb-foot .reset-prog::before { content: "["; color: var(--fg-mute); } .sb-foot .reset-prog::after { content: "]"; color: var(--fg-mute); }
.sb-foot .reset-prog:hover { color: var(--bad); border-color: var(--bad); }
#tree .hit { background: rgba(57,255,106,.08); }
.sb-foot { padding: 5px 12px; border-top: 1px solid var(--line); font-size: 12.5px; color: var(--fg-mute); letter-spacing: .01em; }
.sb-foot span { color: var(--accent-dim); }
.sb-foot a { color: var(--fg-dim); text-decoration: none; }
.sb-foot a:hover { color: var(--accent); text-decoration: underline; }
.sb-foot .build { color: var(--fg-mute); font-size: 11px; margin-left: 10px; letter-spacing: .02em; }

/* ── main ────────────────────────────────────────────────────────────────── */
#main { flex: 1; display: flex; flex-direction: column; min-width: 0; }
#statement-pane { flex: 1 1 45%; min-height: 80px; display: flex; flex-direction: column; overflow: hidden; }
#statement-toolbar { display: flex; gap: 2px; padding: 4px 8px; border-bottom: 1px solid var(--line2); background: var(--bg2); align-items: center; }
#statement-toolbar .tab { background: transparent; border: 1px solid transparent; color: var(--fg-dim); padding: 3px 9px; cursor: pointer; font: inherit; }
#statement-toolbar .tab::before { content: "["; color: var(--fg-mute); }
#statement-toolbar .tab::after { content: "]"; color: var(--fg-mute); }
#statement-toolbar .tab:hover { color: var(--accent); }
#statement-toolbar .tab.active { color: var(--accent); font-weight: 700; text-shadow: var(--glow); }
#statement-toolbar .tab.active::before { content: "[*"; } #statement-toolbar .tab.active::after { content: "*]"; }
.cc-link { margin-left: auto; color: var(--cyan); font-size: 13.5px; }

#statement-body { overflow-y: auto; padding: 14px 22px 60px; }
#statement-body .empty { color: var(--fg-mute); margin-top: 36px; text-align: center; }
#statement-body .empty::before { content: "// "; }
#statement-body h1 { font-size: 22px; color: var(--accent); text-shadow: var(--glow); margin: 0 0 2px; }
#statement-body h1::before { content: "## "; color: var(--fg-mute); }
#statement-body h2 { font-size: 18px; color: var(--amber); margin-top: 1.5em; border-bottom: 1px dashed var(--line2); padding-bottom: 2px; }
#statement-body h2::before { content: "=== "; color: var(--fg-mute); } #statement-body h2::after { content: " ==="; color: var(--fg-mute); }
#statement-body h3 { font-size: 16px; color: var(--cyan); margin-top: 1.2em; }
#statement-body h3::before { content: "--- "; color: var(--fg-mute); }
#statement-body p, #statement-body li { line-height: 1.6; }
#statement-body a { color: var(--cyan); }
#statement-body .meta-row { color: var(--fg-dim); font-size: 13.5px; margin: 4px 0 14px; display: flex; gap: 10px; flex-wrap: wrap; }
#statement-body .meta-row span::before { content: "["; color: var(--fg-mute); } #statement-body .meta-row span::after { content: "]"; color: var(--fg-mute); }
#statement-body pre { background: var(--bg2); border: 1px solid var(--line2); padding: 8px 10px; overflow-x: auto; position: relative; }
#statement-body pre::before { content: ""; }
#statement-body code { font-family: var(--mono); font-size: 14px; background: var(--bg3); padding: 0 3px; border: 1px solid var(--line); }
#statement-body pre code { background: transparent; padding: 0; border: 0; }
#statement-body table { border-collapse: collapse; }
#statement-body td, #statement-body th { border: 1px solid var(--line2); padding: 3px 8px; }
#statement-body th { background: var(--bg3); color: var(--amber); }
#statement-body img { max-width: 100%; filter: var(--img-filter, none); border: 1px solid var(--line2); }
body:not(.light) #statement-body img { filter: brightness(.9) contrast(1.05); }
#statement-body aside { background: var(--bg2) !important; border-left: 2px solid var(--amber); padding: 6px 12px; color: var(--fg-dim); font-size: 14px; }
#statement-body aside::before { content: "! "; color: var(--amber); font-weight: 700; }
#statement-body .sample-block { margin: 8px 0; border: 1px solid var(--line); padding: 6px 8px; }
#statement-body .sample-block .lbl { color: var(--fg-dim); font-size: 13.5px; }
#statement-body .sample-block .lbl::before { content: "$ "; color: var(--accent-dim); }
.hint-card { border: 1px solid var(--line2); margin: 6px 0; }
.hint-card > summary { padding: 6px 10px; cursor: pointer; color: var(--amber); list-style: none; }
.hint-card > summary::-webkit-details-marker { display: none; }
.hint-card > summary::before { content: "[+] "; color: var(--fg-mute); }
.hint-card[open] > summary::before { content: "[-] "; color: var(--fg-mute); }
.hint-card > div { padding: 0 10px 10px; border-top: 1px dashed var(--line2); margin-top: 2px; }

/* katex tint */
.katex { color: var(--fg); }

/* ── dragbar ─────────────────────────────────────────────────────────────── */
#dragbar { height: 5px; background: var(--bg2); border-top: 1px solid var(--line2); border-bottom: 1px solid var(--line2); cursor: ns-resize; }
#dragbar:hover { background: var(--accent-dim); }

/* ── editor ──────────────────────────────────────────────────────────────── */
#editor-pane { flex: 1 1 55%; min-height: 120px; display: flex; flex-direction: column; overflow: hidden; background: var(--bg); }
#editor-toolbar { display: flex; align-items: center; gap: 6px; padding: 4px 8px; background: var(--bg2); border-bottom: 1px solid var(--line2); }
.lang-pill { color: var(--accent); font-weight: 700; }
.lang-pill::before { content: "<"; color: var(--fg-mute); } .lang-pill::after { content: ">"; color: var(--fg-mute); }
#editor-toolbar button { background: var(--bg3); color: var(--fg); border: 1px solid var(--line2); padding: 3px 9px; cursor: pointer; font: inherit; }
#editor-toolbar button::before { content: "["; color: var(--fg-mute); } #editor-toolbar button::after { content: "]"; color: var(--fg-mute); }
#editor-toolbar button:hover:not(:disabled) { color: var(--accent); border-color: var(--accent-dim); }
#editor-toolbar button:disabled { opacity: .4; cursor: default; }
#run-btn { color: var(--accent) !important; border-color: var(--accent-dim) !important; font-weight: 700; }
#run-btn:hover:not(:disabled) { background: var(--accent) !important; color: #000 !important; }
.spacer { flex: 1; }
#run-status { font-size: 13.5px; color: var(--fg-dim); }
#run-status::before { content: "» "; color: var(--accent-dim); }
#run-status:empty::before { content: ""; }
#editor { flex: 1; min-height: 80px; border-bottom: 1px solid var(--line2); }
#io-panel { display: flex; gap: 1px; background: var(--line2); flex: 0 0 220px; min-height: 0; }
.io-col { background: var(--bg); flex: 1; display: flex; flex-direction: column; overflow: hidden; }
.io-col > label { font-size: 12.5px; color: var(--fg-dim); padding: 4px 10px 2px; text-transform: uppercase; letter-spacing: .06em; }
.io-col > label::before { content: "── "; color: var(--fg-mute); } .io-col > label::after { content: " ──"; color: var(--fg-mute); }
#custom-input { flex: 1; resize: none; border: 0; background: var(--bg); color: var(--fg); font: 14px/1.5 var(--mono); padding: 2px 10px 10px; outline: none; }
#custom-input::placeholder { color: var(--fg-mute); }
#results { flex: 1; min-height: 0; overflow-y: auto; padding: 2px 10px 12px; font-size: 14px; }
#results .muted { color: var(--fg-mute); }
#results .muted::before { content: "// "; }
.verdict { border: 1px solid var(--line2); margin: 5px 0; }
.verdict > summary { padding: 4px 8px; display: flex; gap: 8px; align-items: center; cursor: pointer; list-style: none; }
.verdict > summary::-webkit-details-marker { display: none; }
.verdict.ac > summary { border-left: 3px solid var(--good); } .verdict.wa > summary, .verdict.err > summary { border-left: 3px solid var(--bad); }
.verdict .tag { font-weight: 700; font-size: 12.5px; padding: 0 5px; border: 1px solid; }
.verdict.ac .tag { color: var(--good); border-color: var(--good); } .verdict.wa .tag, .verdict.err .tag { color: var(--bad); border-color: var(--bad); }
.verdict .io-grid { display: grid; grid-template-columns: 1fr 1fr 1fr; gap: 1px; background: var(--line2); border-top: 1px solid var(--line2); }
.verdict .io-grid > div { background: var(--bg); padding: 4px 8px; }
.verdict .io-grid .h { font-size: 11.5px; color: var(--fg-mute); text-transform: uppercase; }
.verdict .io-grid .h::before { content: "// "; }
.verdict pre { margin: 2px 0 0; font: 13px/1.45 var(--mono); white-space: pre-wrap; word-break: break-word; max-height: 160px; overflow: auto; color: var(--fg); }
.summary-line { font-weight: 700; margin: 4px 0 2px; padding: 2px 0; }
.summary-line.ac { color: var(--good); text-shadow: var(--glow); } .summary-line.wa { color: var(--bad); }

/* blinking block cursor accent on the main prompt */
@keyframes blink { 50% { opacity: 0; } }
.sb-head .title::after { animation: none; }

/* zen — editor only */
body.zen #sidebar, body.zen #statement-pane, body.zen #dragbar { display: none; }
body.zen #editor-pane { flex: 1; }
body.zen #app { height: 100vh; }

@media (max-width: 760px) {
  #sidebar { position: fixed; z-index: 20; height: 100%; transform: translateX(-100%); transition: transform .15s; }
  #sidebar.open { transform: none; }
}