/* AI Engineer Interview Prep — standalone static site, no build step */
:root {
  --bg: #0e131a;
  --bg2: #141b25;
  --card: #18202d;
  --card2: #1d2635;
  --border: #2b3648;
  --text: #e8edf4;
  --muted: #9dabbf;
  --faint: #6b7a90;
  --accent: #5aa2ff;
  --accent-dim: #2c5d9e;
  --green: #43c878;
  --amber: #e8b13f;
  --red: #e0685f;
  --radius: 12px;
  --maxw: 980px;
  --font: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue",
          Arial, "Noto Sans", sans-serif;
  --mono: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}
[data-theme="light"] {
  --bg: #f4f6fa;
  --bg2: #ffffff;
  --card: #ffffff;
  --card2: #f0f3f8;
  --border: #dde4ee;
  --text: #1a2330;
  --muted: #55637a;
  --faint: #8a97ab;
  --accent: #1f6feb;
  --accent-dim: #bcd7ff;
  --green: #1e8e4e;
  --amber: #a86e00;
  --red: #c2402f;
}
* { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.65;
  font-size: 16px;
}
a { color: var(--accent); text-decoration: none; }
a:hover { text-decoration: underline; }

/* Top bar */
.topbar {
  position: sticky; top: 0; z-index: 50;
  display: flex; align-items: center; gap: 12px;
  padding: 12px 18px;
  background: var(--bg2);
  border-bottom: 1px solid var(--border);
}
.topbar .brand { font-weight: 700; font-size: 17px; letter-spacing: .2px; }
.topbar .brand small { color: var(--muted); font-weight: 400; }
.topbar .spacer { flex: 1; }
.icon-btn {
  background: var(--card); color: var(--text);
  border: 1px solid var(--border); border-radius: 8px;
  padding: 7px 12px; font-size: 14px; cursor: pointer;
}
.icon-btn:hover { border-color: var(--accent); }
#menuBtn { display: none; }

.layout { display: flex; align-items: flex-start; }

/* Sidebar */
.sidebar {
  position: sticky; top: 57px;
  width: 260px; flex-shrink: 0;
  height: calc(100vh - 57px);
  overflow-y: auto;
  background: var(--bg2);
  border-right: 1px solid var(--border);
  padding: 16px 12px 40px;
}
.nav-group { margin-bottom: 18px; }
.nav-group > .nav-title {
  font-size: 11px; text-transform: uppercase; letter-spacing: 1.2px;
  color: var(--faint); padding: 0 10px 6px;
}
.nav-link {
  display: block; padding: 8px 10px; border-radius: 8px;
  color: var(--muted); font-size: 14.5px;
}
.nav-link:hover { background: var(--card); color: var(--text); text-decoration: none; }
.nav-link.active { background: var(--card2); color: var(--text); font-weight: 600; }

/* Main */
main { flex: 1; min-width: 0; padding: 28px 24px 80px; }
.wrap { max-width: var(--maxw); margin: 0 auto; }
.page { display: none; }
.page.active { display: block; animation: fade .18s ease-in; }
@keyframes fade { from { opacity: 0; } to { opacity: 1; } }

h1 { font-size: 30px; margin: 0 0 6px; letter-spacing: -.3px; }
h2 { font-size: 22px; margin: 34px 0 10px; padding-top: 8px;
     border-top: 1px solid var(--border); }
h3 { font-size: 17px; margin: 22px 0 8px; }
p.lede { color: var(--muted); font-size: 17px; margin-top: 0; }
ul, ol { padding-left: 22px; }
li { margin-bottom: 6px; }
code { font-family: var(--mono); font-size: .88em; background: var(--card2);
       padding: 2px 6px; border-radius: 6px; }

.card {
  background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px; margin: 14px 0;
}
.card h3 { margin-top: 0; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 700px) { .grid2 { grid-template-columns: 1fr; } }

/* Badges */
.badge {
  display: inline-block; font-size: 11.5px; font-weight: 700;
  text-transform: uppercase; letter-spacing: .6px;
  padding: 2px 9px; border-radius: 20px; vertical-align: middle;
  margin-left: 8px; white-space: nowrap;
}
.badge.reported { background: rgba(232,177,63,.14); color: var(--amber);
  border: 1px solid var(--amber); }
.badge.official { background: rgba(67,200,120,.12); color: var(--green);
  border: 1px solid var(--green); }

.disclaimer {
  background: var(--card2); border-left: 4px solid var(--amber);
  padding: 12px 16px; border-radius: 0 10px 10px 0;
  color: var(--muted); font-size: 14.5px; margin: 16px 0;
}
.legend { font-size: 13.5px; color: var(--muted); }

/* Rounds timeline */
.round {
  border: 1px solid var(--border); border-radius: var(--radius);
  padding: 14px 18px; margin: 10px 0; background: var(--card);
}
.round .r-head { display: flex; align-items: baseline; gap: 10px; flex-wrap: wrap; }
.round .r-num {
  font-family: var(--mono); font-size: 12px; color: var(--faint);
  border: 1px solid var(--border); border-radius: 6px; padding: 1px 8px;
}
.round .r-name { font-weight: 700; font-size: 16px; }
.round p { margin: 8px 0 0; color: var(--muted); font-size: 14.5px; }

.sources { font-size: 13.5px; color: var(--faint); }
.sources li { margin-bottom: 3px; word-break: break-all; }

/* Tracker */
.tracker-head { display: flex; gap: 16px; align-items: center; flex-wrap: wrap;
  margin: 18px 0; }
.progress-wrap { flex: 1; min-width: 220px; }
.progress-label { font-size: 13px; color: var(--muted); margin-bottom: 6px; }
.progress { height: 12px; background: var(--card2); border-radius: 8px;
  overflow: hidden; border: 1px solid var(--border); }
.progress > div { height: 100%; width: 0%;
  background: linear-gradient(90deg, var(--accent), var(--green));
  transition: width .25s ease; }
.week { border: 1px solid var(--border); border-radius: var(--radius);
  margin: 12px 0; background: var(--card); overflow: hidden; }
.week-head {
  display: flex; align-items: center; gap: 12px; padding: 12px 16px;
  cursor: pointer; user-select: none;
}
.week-head:hover { background: var(--card2); }
.week-head .w-title { font-weight: 700; }
.week-head .w-sub { color: var(--muted); font-size: 13.5px; }
.week-head .w-count { margin-left: auto; font-family: var(--mono);
  font-size: 13px; color: var(--muted); white-space: nowrap; }
.week-head .chev { color: var(--faint); font-size: 13px; }
.week-days { display: none; padding: 4px 16px 14px; }
.week.open .week-days { display: block; }
.day { display: flex; gap: 12px; align-items: flex-start;
  padding: 9px 4px; border-top: 1px solid var(--border); font-size: 14.5px; }
.day input[type="checkbox"] { width: 18px; height: 18px; margin-top: 3px;
  accent-color: var(--accent); cursor: pointer; flex-shrink: 0; }
.day.done span { text-decoration: line-through; color: var(--faint); }
.day .d-label { font-family: var(--mono); font-size: 12px; color: var(--faint);
  margin-right: 4px; }

/* Workbench */
textarea {
  width: 100%; min-height: 170px; resize: vertical;
  background: var(--bg2); color: var(--text);
  border: 1px solid var(--border); border-radius: 10px;
  padding: 12px 14px; font-family: var(--font); font-size: 14px; line-height: 1.6;
}
textarea:focus { outline: 2px solid var(--accent); border-color: var(--accent); }
.saved-note { font-size: 13px; color: var(--green); min-height: 20px; }
.checklist { list-style: none; padding: 0; }
.checklist li { padding: 10px 4px 10px 34px; position: relative;
  border-bottom: 1px solid var(--border); }
.checklist li::before { content: "☐"; position: absolute; left: 6px;
  color: var(--accent); font-size: 17px; }

.stat-row { display: flex; gap: 14px; flex-wrap: wrap; margin: 16px 0; }
.stat { background: var(--card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 14px 20px; flex: 1; min-width: 150px; }
.stat .n { font-size: 26px; font-weight: 800; }
.stat .l { font-size: 13px; color: var(--muted); }

footer.site { margin-top: 60px; padding-top: 18px;
  border-top: 1px solid var(--border); color: var(--faint); font-size: 13px; }

/* Mobile */
@media (max-width: 900px) {
  #menuBtn { display: inline-block; }
  .sidebar {
    position: fixed; top: 0; left: 0; z-index: 100;
    height: 100vh; width: 280px; padding-top: 70px;
    transform: translateX(-105%); transition: transform .22s ease;
  }
  .sidebar.open { transform: none; box-shadow: 0 0 40px rgba(0,0,0,.5); }
  .scrim { position: fixed; inset: 0; z-index: 90; background: rgba(0,0,0,.5); }
  main { padding: 20px 16px 70px; }
  h1 { font-size: 25px; }
}
@media print { .sidebar, .topbar { display: none; } .page { display: block; } }