:root {
  --bg: #0b0b0c;
  --bg-card: #151517;
  --bg-elev: #1e1e21;
  --border: #2d2d31;
  --text: #ececee;
  --text-dim: #9a9aa1;
  --accent: #d92b2b;
  --accent-dark: #a81f1f;
  --ok: #e6e6ea;
  --danger: #ff5d55;
  --warn: #f0a48f;
  --radius: 10px;
  font-size: 16px;
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: "Segoe UI", system-ui, -apple-system, sans-serif;
  line-height: 1.55;
}

/* ---------- Top bar ---------- */
.topbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 10px 22px;
  background: var(--bg-card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}

.brand { display: flex; align-items: center; gap: 10px; text-decoration: none; color: var(--text); }
.brand-mark {
  background: var(--accent);
  color: #fff;
  font-weight: 800;
  padding: 6px 9px;
  border-radius: 8px;
  font-size: 1.05rem;
  letter-spacing: 0.5px;
}
.brand-text { font-weight: 700; letter-spacing: 1.5px; font-size: 0.85rem; display: flex; flex-direction: column; line-height: 1.2; }
.brand-text small { color: var(--text-dim); font-weight: 400; letter-spacing: 0.4px; font-size: 0.72rem; }

.topnav { display: flex; align-items: center; gap: 18px; }
.topnav a { color: var(--text-dim); text-decoration: none; font-size: 0.95rem; }
.topnav a:hover { color: var(--text); }

.linklike {
  background: none; border: none; color: var(--text-dim);
  font-size: 0.95rem; cursor: pointer; padding: 0; font-family: inherit;
}
.linklike:hover { color: var(--text); }

main { max-width: 980px; margin: 0 auto; padding: 28px 20px 80px; }

h1 { font-size: 1.5rem; margin: 0 0 6px; }
h2 { font-size: 1.2rem; }
.subtitle { color: var(--text-dim); margin: 0 0 24px; }

/* ---------- Cards & layout ---------- */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
}

.course-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(290px, 1fr)); gap: 16px; }

.course-card { display: flex; flex-direction: column; gap: 10px; cursor: pointer; transition: border-color 0.15s; }
.course-card:hover { border-color: var(--accent-dark); }
.course-card h2 { margin: 0; font-size: 1.05rem; }
.course-card p { margin: 0; color: var(--text-dim); font-size: 0.88rem; flex: 1; }

.progress-row { display: flex; align-items: center; gap: 10px; font-size: 0.82rem; color: var(--text-dim); }
.progress-bar { flex: 1; height: 8px; background: var(--bg-elev); border-radius: 4px; overflow: hidden; }
.progress-fill { height: 100%; background: var(--accent); border-radius: 4px; transition: width 0.3s; }

.badge { display: inline-block; padding: 2px 9px; border-radius: 20px; font-size: 0.74rem; font-weight: 600; }
.badge-pass { background: rgba(230, 230, 234, 0.12); color: var(--ok); }
.badge-pending { background: rgba(240, 164, 143, 0.13); color: var(--warn); }
.badge-none { background: var(--bg-elev); color: var(--text-dim); }
.badge-admin { background: rgba(230, 230, 234, 0.10); color: var(--text-dim); border: 1px solid var(--border); }
.badge-inactive { background: rgba(255, 93, 85, 0.15); color: var(--danger); }

/* ---------- Lesson list ---------- */
.lesson-list { display: flex; flex-direction: column; gap: 8px; margin-top: 18px; }
.lesson-item {
  display: flex; align-items: center; gap: 12px;
  padding: 13px 16px;
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  color: var(--text);
  text-decoration: none;
  transition: border-color 0.15s;
}
.lesson-item:hover { border-color: var(--accent-dark); }
.lesson-check {
  width: 24px; height: 24px; border-radius: 50%;
  border: 2px solid var(--border);
  display: flex; align-items: center; justify-content: center;
  font-size: 0.8rem; flex-shrink: 0; color: #fff;
}
.lesson-check.done { background: var(--accent); border-color: var(--accent); }
.lesson-num { color: var(--text-dim); font-size: 0.85rem; width: 1.4em; text-align: right; }

/* ---------- Lesson content ---------- */
.lesson-content { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 28px 32px; margin-top: 16px; }
.lesson-content h1 { font-size: 1.45rem; margin-top: 0; }
.lesson-content h2 { font-size: 1.15rem; margin-top: 1.6em; color: var(--accent); }
.lesson-content h3 { font-size: 1rem; margin-top: 1.4em; }
.lesson-content a { color: var(--accent); }
.lesson-content code {
  background: var(--bg-elev); padding: 2px 6px; border-radius: 5px;
  font-family: Consolas, "Cascadia Code", monospace; font-size: 0.88em;
}
.lesson-content pre { background: var(--bg-elev); padding: 14px 16px; border-radius: 8px; overflow-x: auto; }
.lesson-content pre code { background: none; padding: 0; }
.lesson-content blockquote {
  margin: 1.2em 0; padding: 10px 18px;
  border-left: 3px solid var(--accent);
  background: rgba(217, 43, 43, 0.07);
  border-radius: 0 8px 8px 0;
  color: var(--text);
}
.lesson-content table { border-collapse: collapse; width: 100%; margin: 1.2em 0; font-size: 0.92rem; }
.lesson-content th, .lesson-content td { border: 1px solid var(--border); padding: 8px 12px; text-align: left; vertical-align: top; }
.lesson-content th { background: var(--bg-elev); }
.lesson-content li { margin: 0.35em 0; }

.lesson-actions { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-top: 18px; flex-wrap: wrap; }

/* ---------- Buttons & forms ---------- */
.btn {
  background: var(--accent); color: #fff;
  border: none; border-radius: 8px;
  padding: 10px 20px; font-size: 0.95rem; font-weight: 600;
  cursor: pointer; font-family: inherit;
  transition: background 0.15s;
}
.btn:hover { background: var(--accent-dark); color: #fff; }
.btn:disabled { opacity: 0.5; cursor: default; }
.btn-secondary { background: var(--bg-elev); color: var(--text); border: 1px solid var(--border); }
.btn-secondary:hover { background: var(--border); color: var(--text); }
.btn-danger { background: transparent; color: var(--danger); border: 1px solid var(--danger); }
.btn-danger:hover { background: var(--danger); color: #fff; }
.btn-sm { padding: 6px 12px; font-size: 0.82rem; }

label { display: block; font-size: 0.85rem; color: var(--text-dim); margin: 14px 0 5px; }
input[type="text"], input[type="password"], select {
  width: 100%; padding: 10px 12px;
  background: var(--bg-elev); color: var(--text);
  border: 1px solid var(--border); border-radius: 8px;
  font-size: 0.95rem; font-family: inherit;
}
input:focus, select:focus { outline: none; border-color: var(--accent-dark); }

.auth-wrap { max-width: 400px; margin: 8vh auto 0; }
.auth-logo { text-align: center; margin-bottom: 22px; }
.auth-logo .brand-mark { font-size: 1.6rem; padding: 10px 14px; }
.auth-logo h1 { font-size: 1.15rem; letter-spacing: 2px; margin: 14px 0 2px; }
.auth-logo p { color: var(--text-dim); margin: 0; font-size: 0.9rem; }

.error-box { background: rgba(255, 93, 85, 0.12); border: 1px solid var(--danger); color: #ffb4b0; padding: 10px 14px; border-radius: 8px; margin-top: 14px; font-size: 0.9rem; }
.info-box { background: rgba(240, 164, 143, 0.1); border: 1px solid var(--warn); color: #ffd9cd; padding: 10px 14px; border-radius: 8px; margin: 14px 0; font-size: 0.9rem; }

/* ---------- Quiz ---------- */
.quiz-q { margin-bottom: 22px; }
.quiz-q h3 { margin: 0 0 10px; font-size: 1rem; }
.choice {
  display: flex; gap: 10px; align-items: flex-start;
  padding: 10px 14px; margin: 6px 0;
  background: var(--bg-elev); border: 1px solid var(--border);
  border-radius: 8px; cursor: pointer; font-size: 0.93rem;
}
.choice:hover { border-color: var(--accent-dark); }
.choice input { margin-top: 3px; accent-color: var(--accent); }
.choice.correct { border-color: var(--ok); background: rgba(230, 230, 234, 0.08); }
.choice.incorrect { border-color: var(--danger); background: rgba(255, 93, 85, 0.1); }
.explain { font-size: 0.86rem; color: var(--text-dim); padding: 8px 14px; border-left: 3px solid var(--border); margin-top: 6px; }

.score-banner { text-align: center; padding: 26px; border-radius: var(--radius); margin-bottom: 22px; }
.score-banner.pass { background: rgba(230, 230, 234, 0.07); border: 1px solid var(--ok); }
.score-banner.fail { background: rgba(255, 93, 85, 0.1); border: 1px solid var(--danger); }
.score-banner .big { font-size: 2.4rem; font-weight: 800; }

/* ---------- Admin ---------- */
.table-wrap { overflow-x: auto; margin-top: 16px; }
table.data { border-collapse: collapse; width: 100%; font-size: 0.88rem; }
table.data th, table.data td { padding: 10px 12px; border-bottom: 1px solid var(--border); text-align: left; white-space: nowrap; }
table.data th { color: var(--text-dim); font-weight: 600; font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.5px; }
table.data tbody tr:hover { background: var(--bg-card); }
table.data tr.clickable { cursor: pointer; }

.toolbar { display: flex; gap: 10px; flex-wrap: wrap; align-items: center; margin-top: 6px; }
.toolbar .spacer { flex: 1; }

.cell-progress { display: flex; flex-direction: column; gap: 4px; min-width: 110px; }
.cell-progress .progress-bar { height: 6px; }
.cell-sub { font-size: 0.76rem; color: var(--text-dim); }

.modal-backdrop {
  position: fixed; inset: 0; background: rgba(0,0,0,0.6);
  display: flex; align-items: center; justify-content: center; z-index: 50; padding: 20px;
}
.modal { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius); padding: 24px; width: 100%; max-width: 420px; }
.modal h2 { margin-top: 0; }

.temp-pass {
  font-family: Consolas, monospace; font-size: 1.3rem; text-align: center;
  background: var(--bg-elev); border: 1px dashed var(--accent);
  padding: 14px; border-radius: 8px; margin: 14px 0; letter-spacing: 1px;
}

/* ---------- Toast ---------- */
.toast {
  position: fixed; bottom: 24px; left: 50%; transform: translateX(-50%);
  background: var(--bg-elev); border: 1px solid var(--accent);
  color: var(--text); padding: 12px 22px; border-radius: 10px;
  font-size: 0.92rem; z-index: 100; box-shadow: 0 6px 24px rgba(0,0,0,0.4);
}

.breadcrumb { font-size: 0.85rem; color: var(--text-dim); margin-bottom: 14px; }
.breadcrumb a { color: var(--text-dim); text-decoration: none; }
.breadcrumb a:hover { color: var(--accent); }

@media (max-width: 640px) {
  .brand-text { display: none; }
  main { padding: 18px 12px 60px; }
  .lesson-content { padding: 20px 16px; }
}