:root {
  --green: #00693e;
  --green-d: #004f2f;
  --gold: #f0a500;
  --bg: #f4f6f5;
  --card: #ffffff;
  --ink: #1c2b25;
  --muted: #6b7c74;
  --line: #e2e8e4;
  --ok: #1a7f37;
  --ok-bg: #e7f5ea;
  --bad: #c62828;
  --bad-bg: #fdecec;
  --shadow: 0 1px 3px rgba(0, 0, 0, .07), 0 8px 24px rgba(0, 0, 0, .05);
  --radius: 14px;
}

* { box-sizing: border-box; }
html, body { margin: 0; }
body {
  font-family: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--ink);
  line-height: 1.55;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
.wrap { width: min(960px, 92vw); margin: 0 auto; }
a { color: var(--green); text-decoration: none; }

/* ---------- top bar ---------- */
#topbar { background: var(--green); color: #fff; box-shadow: var(--shadow); position: sticky; top: 0; z-index: 20; }
.bar { display: flex; align-items: center; gap: 18px; height: 60px; }
.brand { color: #fff; font-weight: 700; font-size: 1.12rem; display: flex; align-items: center; gap: 6px; }
#mainnav { display: flex; gap: 4px; margin-left: 8px; flex: 1; }
#mainnav a { color: #dff0e8; padding: 7px 12px; border-radius: 9px; font-weight: 500; font-size: .95rem; }
#mainnav a:hover { background: rgba(255, 255, 255, .12); color: #fff; }
#mainnav a.active { background: #fff; color: var(--green-d); }
.userbox { display: flex; align-items: center; gap: 10px; font-size: .9rem; }
#who { opacity: .95; }

main { flex: 1; padding: 26px 0 48px; }
footer { background: #fff; border-top: 1px solid var(--line); color: var(--muted); font-size: .85rem; padding: 16px 0; text-align: center; }

/* ---------- generic ---------- */
.card { background: var(--card); border: 1px solid var(--line); border-radius: var(--radius); box-shadow: var(--shadow); padding: 22px; }
.card + .card { margin-top: 18px; }
h1 { font-size: 1.5rem; margin: 0 0 4px; }
h2 { font-size: 1.15rem; margin: 0 0 14px; }
.sub { color: var(--muted); margin: 0 0 20px; }
.muted { color: var(--muted); }

.btn {
  font: inherit; font-weight: 600; cursor: pointer;
  background: var(--green); color: #fff; border: 1px solid var(--green);
  padding: 10px 18px; border-radius: 10px; transition: .15s;
}
.btn:hover { background: var(--green-d); border-color: var(--green-d); }
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn.ghost { background: transparent; color: var(--green); }
.btn.ghost:hover { background: #eef4f1; }
.btn.gold { background: var(--gold); border-color: var(--gold); color: #3a2c00; }
.btn.gold:hover { filter: brightness(.95); }
.btn.sm { padding: 6px 12px; font-size: .85rem; border-radius: 8px; }
.btn.ghost.sm { color: #eafff4; border-color: transparent; }
.btn.ghost.sm:hover { background: rgba(255, 255, 255, .15); }
.row { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; }
.spread { justify-content: space-between; }

label.field { display: block; margin-bottom: 12px; font-size: .9rem; font-weight: 500; }
label.field input, label.field select {
  width: 100%; font: inherit; margin-top: 4px;
  padding: 10px 12px; border: 1px solid var(--line); border-radius: 10px; background: #fff;
}

/* ---------- login ---------- */
.auth { max-width: 400px; margin: 6vh auto 0; }
.auth h1 { text-align: center; }
.auth .sub { text-align: center; }
.tabs { display: flex; gap: 6px; margin-bottom: 18px; background: #eef2f0; padding: 4px; border-radius: 12px; }
.tabs button { flex: 1; border: 0; background: transparent; font: inherit; font-weight: 600; padding: 8px; border-radius: 9px; cursor: pointer; color: var(--muted); }
.tabs button.active { background: #fff; color: var(--green); box-shadow: var(--shadow); }
.err { color: var(--bad); font-size: .88rem; min-height: 1.2em; margin: 2px 0 10px; }

/* ---------- dashboard ---------- */
.stat-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(150px, 1fr)); gap: 12px; }
.stat { background: #f2f7f4; border: 1px solid var(--line); border-radius: 12px; padding: 14px 16px; }
.stat b { display: block; font-size: 1.7rem; line-height: 1.2; color: var(--green-d); }
.stat span { font-size: .82rem; color: var(--muted); }

.quick { display: grid; grid-template-columns: 1fr 1fr; gap: 12px; margin-top: 4px; }
.quick button { text-align: left; padding: 16px; border-radius: 12px; border: 1px solid var(--line); background: #fff; cursor: pointer; font: inherit; transition: .15s; }
.quick button:hover { border-color: var(--green); background: #f4faf7; }
.quick button b { display: block; font-size: 1rem; margin-bottom: 2px; }
.quick button span { font-size: .85rem; color: var(--muted); }

.cat-list { display: grid; gap: 10px; }
.cat {
  display: flex; justify-content: space-between; gap: 16px; align-items: center;
  padding: 14px 16px; border: 1px solid var(--line); border-radius: 12px; background: #fff;
}
.cat:hover { border-color: var(--green); }
.cat-main { flex: 1; min-width: 0; }
.cat .name { font-weight: 600; font-size: .95rem; margin-bottom: 3px; }
.cat-btns { display: flex; flex-direction: column; gap: 6px; flex-shrink: 0; align-items: stretch; }
.cat-btns .btn { white-space: nowrap; }
.bar-split { display: flex; height: 6px; background: #edf1ef; border-radius: 99px; margin-top: 8px; overflow: hidden; max-width: 320px; }
.bar-split i { display: block; height: 100%; }
.bar-split i.g { background: var(--ok); }
.bar-split i.r { background: var(--bad); }

/* ---------- quiz ---------- */
.quiz-title { text-align: center; font-size: 1.15rem; margin: 0 0 14px; }
.quiz-layout { display: grid; grid-template-columns: 1fr 260px; gap: 22px; align-items: start; }
.quiz-main { min-width: 0; }
.quiz-aside { position: sticky; top: 76px; border: 1px solid var(--line); border-radius: 12px; padding: 14px; background: #fbfdfc; }
.aside-head { text-align: center; font-weight: 600; padding-bottom: 10px; border-bottom: 1px solid var(--line); margin-bottom: 12px; }
.qtype { background: #f1f5f3; border-radius: 8px; padding: 8px 12px; font-weight: 600; font-size: .9rem; margin-bottom: 12px; }
.exp-head { font-weight: 600; color: var(--green-d); margin: 4px 0 6px; }
.result-rows { display: grid; gap: 2px; margin-top: 14px; }
.result-rows .row { padding: 12px 0; border-bottom: 1px solid var(--line); }
.review-slot { margin-top: 12px; }

.quizhead { display: flex; justify-content: space-between; align-items: center; gap: 12px; margin-bottom: 14px; flex-wrap: wrap; }
.pill { background: #eaf3ee; color: var(--green-d); border-radius: 99px; padding: 4px 12px; font-size: .82rem; font-weight: 600; }
.progressbar { height: 8px; background: #e9eeeb; border-radius: 99px; overflow: hidden; margin-bottom: 18px; }
.progressbar i { display: block; height: 100%; background: var(--green); transition: width .25s; }

.qstem { font-size: 1.08rem; font-weight: 600; margin: 6px 0 16px; white-space: pre-wrap; }
.opts { display: grid; gap: 10px; }
.opt {
  display: flex; gap: 12px; align-items: flex-start; padding: 12px 14px;
  border: 1.5px solid var(--line); border-radius: 12px; cursor: pointer; background: #fff; transition: .12s;
}
.opt:hover { border-color: var(--green); background: #f6faf8; }
.opt .k { font-weight: 700; color: var(--green); flex-shrink: 0; width: 1.4em; }
.opt.sel { border-color: var(--green); background: #eef6f1; }
.opt.correct { border-color: var(--ok); background: var(--ok-bg); }
.opt.correct .k { color: var(--ok); }
.opt.wrong { border-color: var(--bad); background: var(--bad-bg); }
.opt.wrong .k { color: var(--bad); }
.opt.disabled { cursor: default; }

.feedback { margin-top: 16px; border-radius: 12px; padding: 14px 16px; font-size: .95rem; }
.feedback.ok { background: var(--ok-bg); border: 1px solid #b8e0c2; }
.feedback.bad { background: var(--bad-bg); border: 1px solid #f2c4c4; }
.feedback h4 { margin: 0 0 6px; font-size: .95rem; }
.feedback .exp { white-space: pre-wrap; color: #33413b; }

.quiznav { display: flex; justify-content: space-between; margin-top: 20px; gap: 10px; }

.palette { display: flex; flex-wrap: wrap; gap: 6px; margin-top: 4px; }
.palette button {
  width: 34px; height: 34px; border-radius: 8px; border: 1px solid var(--line);
  background: #fff; font: inherit; font-size: .8rem; cursor: pointer; font-weight: 600;
}
.palette button.answered { background: var(--green); color: #fff; border-color: var(--green); }
.palette button.flagcur { outline: 2px solid var(--gold); }
.palette button.ok { background: var(--ok); color: #fff; border-color: var(--ok); }
.palette button.no { background: var(--bad); color: #fff; border-color: var(--bad); }

.timer { font-variant-numeric: tabular-nums; font-weight: 700; color: var(--green-d); }
.timer.warn { color: var(--bad); }

.result-hero { text-align: center; padding: 10px 0 4px; }
.result-hero .big { font-size: 3rem; font-weight: 700; color: var(--green); }
.ring { --p: 0; width: 132px; height: 132px; border-radius: 50%; margin: 6px auto 12px;
  background: conic-gradient(var(--green) calc(var(--p) * 1%), #e9eeeb 0);
  display: grid; place-items: center; }
.ring i { width: 104px; height: 104px; background: #fff; border-radius: 50%; display: grid; place-items: center; font-weight: 700; font-size: 1.5rem; font-style: normal; }

.review-item { border: 1px solid var(--line); border-radius: 12px; padding: 14px; margin-top: 12px; }
.review-item.ok { border-left: 4px solid var(--ok); }
.review-item.no { border-left: 4px solid var(--bad); }

.toast-wrap { position: fixed; left: 50%; bottom: 24px; transform: translateX(-50%); z-index: 60; display: grid; gap: 8px; }
.toast { background: #223; color: #fff; padding: 10px 16px; border-radius: 10px; font-size: .9rem; box-shadow: var(--shadow); }
.toast.err { background: var(--bad); }

.center { text-align: center; padding: 40px 0; color: var(--muted); }
.spin { width: 26px; height: 26px; border: 3px solid var(--line); border-top-color: var(--green); border-radius: 50%; animation: sp 1s linear infinite; margin: 0 auto 10px; }
@keyframes sp { to { transform: rotate(360deg); } }

@media (max-width: 860px) {
  .quiz-layout { grid-template-columns: 1fr; }
  .quiz-aside { position: static; order: -1; }
}
@media (max-width: 640px) {
  .bar { height: auto; padding: 10px 0; flex-wrap: wrap; }
  #mainnav { order: 3; width: 100%; }
  .quick { grid-template-columns: 1fr; }
  .cat { flex-direction: column; align-items: stretch; }
  .cat-btns { flex-direction: row; }
  .quiznav { flex-wrap: wrap; }
  .quiznav .btn { flex: 1; }
}