:root {
  --bg: #fbf1ec; --card: #fffdf8; --text: #2a1a16; --muted: #6f534b; --border: #e6d6cf;
  --primary: #b8301c; --primary-2: #b8301c; --accent: #d9a441;
  --ok: #2f7d4f; --ok-bg: #e4f2e8; --bad: #b8301c; --bad-bg: #fbe3de; --warn-bg: #fbeed2;
  --phy: #b8301c; --chem: #2f7d4f; --math: #7a4b8f;
  --radius: 14px; --shadow: 0 1px 2px rgba(42,26,22,.06);
  --font: "Anek Kannada", "Archivo", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --font-head: "Noto Serif Kannada", "Anek Kannada", Georgia, serif;
}
* { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; }
body { margin: 0; font-family: var(--font); background: var(--bg); color: var(--text); line-height: 1.5; padding-bottom: 70px; }
a { color: var(--primary); text-decoration: none; }
h1 { font-size: 1.7rem; margin: .5rem 0; font-family: var(--font-head); line-height: 1.25; } h2 { font-size: 1.2rem; margin: 1rem 0 .5rem; font-family: var(--font-head); } h3 { font-size: 1.05rem; margin: .75rem 0 .25rem; }
p { margin: .5rem 0; }
.hidden { display: none !important; }
.muted { color: var(--muted); font-size: .9rem; }
.container { max-width: 900px; margin: 0 auto; padding: 12px 16px 24px; }
.loading { text-align: center; padding: 3rem; color: var(--muted); }

.topbar { position: sticky; top: 0; z-index: 20; background: var(--bg); color: var(--text); display: flex; align-items: center; gap: 12px; padding: 10px 16px; border-bottom: 1px solid var(--border); }
.brand { color: var(--text); font-weight: 700; font-size: 1.05rem; display: flex; align-items: center; gap: 10px; line-height: 1.1; }
.brand small { display: block; font-size: .62rem; letter-spacing: .12em; color: var(--muted); font-weight: 600; }
.logo { background: var(--primary); color: #fff; width: 36px; height: 36px; border-radius: 8px; display: inline-grid; place-items: center; font-weight: 800; font-family: var(--font-head); font-size: 1.1rem; }
.topnav { display: none; gap: 16px; margin-left: auto; }
.topnav a { color: var(--text); font-weight: 600; }
.topnav a:hover { color: var(--primary); }
.topbar .btn { margin-left: 8px; }
.topbar .btn.ghost + .btn { margin-left: 8px; }
.topnav + .btn { margin-left: 12px; }

.bottomnav { position: fixed; bottom: 0; left: 0; right: 0; background: var(--card); border-top: 1px solid var(--border); display: flex; z-index: 20; padding-bottom: env(safe-area-inset-bottom); }
.bottomnav a { flex: 1; text-align: center; padding: 6px 2px 5px; font-size: .58rem; letter-spacing: .08em; color: var(--muted); display: flex; flex-direction: column; align-items: center; gap: 1px; text-transform: uppercase; font-weight: 600; }
.bottomnav a .kn { font-size: .8rem; letter-spacing: 0; text-transform: none; color: var(--text); }
.bottomnav a .ico { font-size: 1.25rem; }
.bottomnav a.active, .bottomnav a.active .kn { color: var(--primary); }
@media (min-width: 720px) { .topnav { display: flex; } .bottomnav { display: none; } body { padding-bottom: 0; } }

.card { background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 14px 16px; box-shadow: var(--shadow); margin: 10px 0; }
.card.link { display: block; color: inherit; cursor: pointer; transition: transform .1s; }
.card.link:active { transform: scale(.99); }
.grid { display: grid; gap: 10px; grid-template-columns: 1fr; }
.grid.three { grid-template-columns: repeat(3, 1fr); }
.grid.three .card { padding: 10px 6px; }
@media (min-width: 560px) { .grid.two { grid-template-columns: 1fr 1fr; } .grid.three { grid-template-columns: repeat(3, 1fr); } }
.row { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.spread { justify-content: space-between; }
.stack { display: flex; flex-direction: column; gap: 8px; }

.btn { display: inline-flex; align-items: center; justify-content: center; gap: 6px; background: var(--primary); color: #fff; border: 0; border-radius: 999px; padding: 10px 18px; font-size: 1rem; font-weight: 600; cursor: pointer; text-decoration: none; font-family: var(--font); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.secondary { background: #f1e3dc; color: var(--text); }
.btn.ghost { background: transparent; color: var(--primary); border: 1px solid var(--border); }
.btn.danger { background: var(--bad); }
.btn.small { padding: 6px 12px; font-size: .85rem; }
.btn.block { width: 100%; }

.subject-card { border-left: 6px solid var(--phy); }
.subject-card[data-s="chemistry"] { border-left-color: var(--chem); }
.subject-card[data-s="maths"] { border-left-color: var(--math); }
.pill { display: inline-block; font-size: .75rem; padding: 2px 9px; border-radius: 999px; background: #f1e3dc; color: var(--primary); font-weight: 600; }
.pill.ok { background: var(--ok-bg); color: var(--ok); } .pill.bad { background: var(--bad-bg); color: var(--bad); } .pill.warn { background: var(--warn-bg); color: #92400e; }
.pill.easy { background: var(--ok-bg); color: var(--ok); } .pill.medium { background: var(--warn-bg); color: #92400e; } .pill.hard { background: var(--bad-bg); color: var(--bad); }

.progress { height: 8px; background: #efe0d8; border-radius: 999px; overflow: hidden; }
.progress > span { display: block; height: 100%; background: var(--ok); }

.tabs { display: flex; gap: 4px; border-bottom: 2px solid var(--border); margin: 8px 0 12px; overflow-x: auto; }
.tabs button { background: none; border: 0; padding: 10px 14px; font-size: .95rem; font-weight: 600; color: var(--muted); cursor: pointer; border-bottom: 3px solid transparent; margin-bottom: -2px; white-space: nowrap; }
.tabs button.active { color: var(--primary); border-bottom-color: var(--primary); }

.question { font-size: 1.05rem; margin-bottom: 12px; }
.options { display: grid; gap: 8px; }
.option { display: flex; gap: 10px; align-items: flex-start; width: 100%; text-align: left; background: var(--card); border: 2px solid var(--border); border-radius: 10px; padding: 10px 12px; font-size: 1rem; cursor: pointer; color: var(--text); }
.option .key { flex: 0 0 26px; height: 26px; border-radius: 50%; background: #f1e3dc; color: var(--primary); font-weight: 700; display: grid; place-items: center; font-size: .85rem; }
.option.selected { border-color: var(--primary); background: #fbe9e4; }
.option.correct { border-color: var(--ok); background: var(--ok-bg); }
.option.wrong { border-color: var(--bad); background: var(--bad-bg); }
.option:disabled { cursor: default; }
.explain { margin-top: 12px; padding: 12px; background: #f6ece6; border-left: 4px solid var(--accent); border-radius: 8px; }
.notes { font-size: .98rem; } .notes h3 { margin-top: 1rem; color: var(--primary); font-family: var(--font-head); }
.notes ul { padding-left: 1.2rem; } .notes li { margin: .25rem 0; }
.notes table { border-collapse: collapse; font-size: .9rem; margin: .5rem 0; display: block; overflow-x: auto; max-width: 100%; }
.notes td, .notes th { white-space: nowrap; }
.notes td, .notes th { border: 1px solid var(--border); padding: 4px 8px; text-align: left; }
.katex { font-size: 1.05em; }
.katex-display { overflow-x: auto; overflow-y: hidden; padding: 4px 0; }

/* Exam */
.exam-top { position: sticky; top: 52px; z-index: 10; background: var(--bg); padding: 6px 0; display: flex; align-items: center; justify-content: space-between; gap: 8px; }
.timer { font-variant-numeric: tabular-nums; font-weight: 700; font-size: 1.1rem; background: var(--card); padding: 4px 10px; border-radius: 8px; border: 1px solid var(--border); }
.timer.low { color: var(--bad); border-color: var(--bad); }
.palette { display: grid; grid-template-columns: repeat(auto-fill, minmax(38px, 1fr)); gap: 6px; }
.palette button { height: 38px; border-radius: 8px; border: 1px solid var(--border); background: var(--card); font-weight: 600; cursor: pointer; }
.palette button.answered { background: var(--ok-bg); border-color: var(--ok); }
.palette button.review { background: #ede9fe; border-color: #7c3aed; }
.palette button.current { outline: 3px solid var(--primary); }
.legend { display: flex; gap: 12px; font-size: .8rem; flex-wrap: wrap; margin: 8px 0; }
.legend i { display: inline-block; width: 12px; height: 12px; border-radius: 3px; border: 1px solid var(--border); vertical-align: middle; margin-right: 4px; }

.score-big { font-size: 2.5rem; font-weight: 800; color: var(--primary); }
.stat { text-align: center; } .stat b { display: block; font-size: 1.4rem; }
.table { width: 100%; border-collapse: collapse; font-size: .92rem; }
.table th, .table td { text-align: left; padding: 8px 6px; border-bottom: 1px solid var(--border); }
.table th { color: var(--muted); font-weight: 600; font-size: .8rem; text-transform: uppercase; }

label.field { display: flex; flex-direction: column; gap: 4px; font-weight: 600; font-size: .9rem; }
select, input[type=number] { font-size: 1rem; padding: 8px 10px; border-radius: 8px; border: 1px solid var(--border); background: var(--card); }
.checks { display: flex; gap: 12px; flex-wrap: wrap; }
.checks label { display: flex; gap: 6px; align-items: center; font-weight: 500; }

.toast { position: fixed; bottom: 80px; left: 50%; transform: translateX(-50%); background: var(--text); color: #fff; padding: 10px 16px; border-radius: 10px; z-index: 50; font-size: .9rem; max-width: 90vw; }
.empty { text-align: center; padding: 2rem 1rem; color: var(--muted); }
.breadcrumb { font-size: .85rem; color: var(--muted); margin-bottom: 4px; }
.breadcrumb a { color: var(--muted); }
kbd { background: #f1e3dc; padding: 1px 5px; border-radius: 4px; font-size: .8rem; }

/* Guided home */
.hero { background: var(--card); border: 1px solid var(--border); border-top: 4px solid var(--accent); }
.hero h1 { font-size: 1.9rem; margin: 0 0 6px; }
.steps { display: grid; gap: 10px; }
.step { display: flex; gap: 12px; align-items: center; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 12px 14px; color: inherit; }
.step .num { flex: 0 0 38px; height: 38px; border-radius: 50%; background: var(--primary); color: #fff; display: grid; place-items: center; font-weight: 800; font-family: var(--font-head); font-size: 1.1rem; }
.step b { display: block; font-size: 1.05rem; } .step .muted { font-size: .85rem; }
.step .go { margin-left: auto; color: var(--primary); font-weight: 700; white-space: nowrap; }
.step.done .num { background: var(--ok); }
.kicker { font-size: .72rem; letter-spacing: .12em; text-transform: uppercase; color: var(--primary); font-weight: 700; }