:root {
  --primary: #1a56db;
  --primary-dark: #1240a8;
  --success: #0e9f6e;
  --danger: #e02424;
  --bg: #f3f6fb;
  --card: #ffffff;
  --text: #1f2937;
  --muted: #6b7280;
  --border: #e5e7eb;
  --radius: 10px;
  --shadow: 0 1px 3px rgba(16, 24, 40, .08), 0 1px 2px rgba(16, 24, 40, .04);
}

* { box-sizing: border-box; }
body {
  margin: 0;
  font-family: 'Segoe UI', 'Noto Sans Thai', 'Microsoft YaHei', system-ui, sans-serif;
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
h1, h2, h3 { margin: 0 0 14px; }
code { background: #eef2ff; padding: 1px 6px; border-radius: 4px; font-size: .85em; }

/* ---------- Top bar ---------- */
.topbar { background: var(--card); border-bottom: 1px solid var(--border); box-shadow: var(--shadow); }
.topbar-inner {
  max-width: 1280px; margin: 0 auto; padding: 10px 20px;
  display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap;
}
.brand { font-weight: 700; color: var(--text); font-size: 16px; display: flex; align-items: center; gap: 8px; }
.brand:hover { text-decoration: none; }
.brand-mark {
  background: var(--primary); color: #fff; border-radius: 8px;
  padding: 4px 8px; font-size: 13px; letter-spacing: 1px;
}
.topnav { display: flex; align-items: center; gap: 10px; flex-wrap: wrap; }
.lang-switch { display: flex; gap: 2px; background: var(--bg); border-radius: 8px; padding: 3px; }
.lang-switch a { padding: 3px 10px; border-radius: 6px; font-size: 13px; color: var(--muted); }
.lang-switch a.active { background: var(--card); color: var(--primary); font-weight: 600; box-shadow: var(--shadow); }
.lang-switch a:hover { text-decoration: none; }
.user-chip { font-size: 13px; color: var(--muted); }

/* ---------- Layout ---------- */
.page { flex: 1; }
.container { max-width: 1280px; margin: 24px auto; padding: 0 20px; width: 100%; }
.container.narrow { max-width: 760px; }
.footer { text-align: center; padding: 18px; color: var(--muted); font-size: 13px; }
.hero { text-align: center; margin: 30px 0 22px; }
.hero h1 { font-size: 26px; }
.center { text-align: center; }
.muted { color: var(--muted); }
.small { font-size: 13px; }
.link { cursor: pointer; user-select: none; }

/* ---------- Cards ---------- */
.card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 22px; margin-bottom: 20px; box-shadow: var(--shadow);
}

/* ---------- Tabs ---------- */
.tabs { display: flex; gap: 6px; margin-bottom: 20px; border-bottom: 2px solid var(--border); }
.tab {
  padding: 10px 22px; font-weight: 600; color: var(--muted);
  border-bottom: 3px solid transparent; margin-bottom: -2px;
}
.tab:hover { text-decoration: none; color: var(--primary); }
.tab.active { color: var(--primary); border-bottom-color: var(--primary); }

/* ---------- Forms ---------- */
.form label { display: block; margin-bottom: 14px; font-weight: 600; font-size: 14px; }
.form input, .form select, .form textarea {
  display: block; width: 100%; margin-top: 6px; padding: 10px 12px;
  border: 1px solid var(--border); border-radius: 8px; font-size: 14px; font-family: inherit;
  background: #fff;
}
.form input:focus, .form select:focus, .form textarea:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(26, 86, 219, .15);
}
.form .radio { font-weight: 400; display: flex; align-items: center; gap: 8px; margin-bottom: 8px; }
.form .radio input { display: inline; width: auto; margin: 0; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 0 16px; }
.grid2-loose { display: grid; grid-template-columns: 1fr 1fr; gap: 20px; }
@media (max-width: 700px) { .grid2, .grid2-loose { grid-template-columns: 1fr; } }
fieldset.source-box, .terms-box {
  border: 1px solid var(--border); border-radius: 8px; padding: 14px 16px; margin: 0 0 16px;
}
fieldset.source-box legend { font-weight: 600; font-size: 14px; padding: 0 6px; }
.captcha-row { display: flex; gap: 10px; align-items: center; }
.captcha-row img { border: 1px solid var(--border); border-radius: 8px; cursor: pointer; height: 48px; background: #fff; }
.captcha-row input { flex: 1; }

/* ---------- Buttons ---------- */
.btn {
  display: inline-block; padding: 10px 18px; border-radius: 8px; border: none;
  font-size: 14px; font-weight: 600; cursor: pointer; font-family: inherit;
  transition: background .15s;
}
.btn:hover { text-decoration: none; }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-success { background: var(--success); color: #fff; }
.btn-success:hover { filter: brightness(.92); }
.btn-danger { background: var(--danger); color: #fff; }
.btn-danger:hover { filter: brightness(.92); }
.btn-outline { background: transparent; color: var(--primary); border: 1px solid var(--primary); }
.btn-ghost { background: transparent; color: var(--muted); border: 1px solid var(--border); }
.btn-block { width: 100%; }
.btn-sm { padding: 5px 12px; font-size: 13px; }

/* ---------- Alerts & badges ---------- */
.alert { padding: 12px 16px; border-radius: 8px; margin-bottom: 16px; font-size: 14px; }
.alert.error { background: #fde8e8; color: #9b1c1c; border: 1px solid #f8b4b4; }
.alert.success { background: #def7ec; color: #03543f; border: 1px solid #84e1bc; }
.alert.info { background: #e1effe; color: #1e429f; border: 1px solid #a4cafe; }
.badge {
  display: inline-block; padding: 2px 10px; border-radius: 999px;
  background: #eef2ff; color: var(--primary-dark); font-size: 12px; font-weight: 600; white-space: nowrap;
}
.badge-green { background: #def7ec; color: #03543f; }
.badge-red { background: #fde8e8; color: #9b1c1c; }
.badge-blue { background: #e1effe; color: #1e429f; }
.badge-gray { background: #f3f4f6; color: #4b5563; }

/* ---------- Tables ---------- */
table.data { width: 100%; border-collapse: collapse; font-size: 14px; }
table.data th {
  text-align: left; padding: 10px 12px; border-bottom: 2px solid var(--border);
  color: var(--muted); font-size: 12px; text-transform: uppercase; letter-spacing: .4px;
}
table.data td { padding: 10px 12px; border-bottom: 1px solid var(--border); vertical-align: middle; }
table.data tr:last-child td { border-bottom: none; }
table.kv th { text-align: left; padding: 8px 16px 8px 0; color: var(--muted); font-weight: 600; width: 180px; }
table.kv td { padding: 8px 0; }
.actions-cell { display: flex; gap: 6px; flex-wrap: wrap; align-items: center; }
form.inline { display: inline-flex; gap: 6px; align-items: center; }
.status-form select { padding: 6px 8px; border: 1px solid var(--border); border-radius: 6px; font-family: inherit; }
td select, td input[type="text"] { padding: 6px 8px; border: 1px solid var(--border); border-radius: 6px; font-family: inherit; }

/* ---------- Stats ---------- */
.stat-row { display: grid; grid-template-columns: repeat(auto-fit, minmax(170px, 1fr)); gap: 14px; margin-bottom: 20px; }
.stat-card {
  background: var(--card); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 16px 18px; box-shadow: var(--shadow); display: flex; flex-direction: column; gap: 4px;
}
.stat-card.highlight { border-color: var(--primary); background: linear-gradient(180deg, #eff4ff, #fff); }
.stat-label { font-size: 12px; color: var(--muted); text-transform: uppercase; letter-spacing: .4px; }
.stat-value { font-size: 26px; font-weight: 700; }
.stat-value.code { color: var(--primary); letter-spacing: 1px; }

/* ---------- Timeline (student) ---------- */
.timeline { display: flex; flex-wrap: wrap; gap: 4px; margin: 18px 0; }
.timeline-step { flex: 1; min-width: 100px; text-align: center; position: relative; padding-top: 4px; }
.timeline-step .dot {
  display: inline-flex; width: 32px; height: 32px; border-radius: 50%;
  background: #e5e7eb; color: var(--muted); align-items: center; justify-content: center; font-weight: 700; font-size: 13px;
}
.timeline-step.done .dot { background: var(--success); color: #fff; }
.timeline-step.current .dot { background: var(--primary); color: #fff; box-shadow: 0 0 0 4px rgba(26, 86, 219, .2); }
.timeline-step .label { display: block; margin-top: 6px; font-size: 12px; color: var(--muted); }
.timeline-step.current .label { color: var(--primary); font-weight: 700; }
.timeline-step.done .label { color: var(--success); }
.status-line { margin-top: 8px; }

/* ---------- Milestones ---------- */
.milestone-track { display: grid; grid-template-columns: repeat(auto-fit, minmax(130px, 1fr)); gap: 12px; margin-bottom: 14px; }
.milestone {
  border: 1px solid var(--border); border-radius: 8px; padding: 12px; text-align: center;
  display: flex; flex-direction: column; gap: 4px; background: #fafafa;
}
.milestone.reached { border-color: var(--success); background: #def7ec; }
.m-count { font-size: 22px; font-weight: 700; }
.m-bonus { color: var(--primary-dark); font-weight: 600; }
.m-state { font-size: 12px; color: var(--muted); }
.milestone.reached .m-state { color: #03543f; font-weight: 600; }
.progress { height: 10px; background: #e5e7eb; border-radius: 999px; overflow: hidden; }
.progress-bar { height: 100%; background: var(--primary); border-radius: 999px; transition: width .3s; }

/* ---------- Admin layout ---------- */
.admin-layout { display: flex; max-width: 1400px; margin: 0 auto; width: 100%; flex: 1; align-items: flex-start; }
.sidebar {
  width: 230px; flex-shrink: 0; padding: 24px 0 24px 20px; position: sticky; top: 0;
}
.sidebar nav { display: flex; flex-direction: column; gap: 2px; background: var(--card); border: 1px solid var(--border); border-radius: var(--radius); padding: 10px; box-shadow: var(--shadow); }
.sidebar nav a { padding: 9px 14px; border-radius: 8px; color: var(--text); font-size: 14px; }
.sidebar nav a:hover { background: var(--bg); text-decoration: none; }
.sidebar nav a.active { background: var(--primary); color: #fff; font-weight: 600; }
.admin-content { flex: 1; padding: 24px 20px; min-width: 0; overflow-x: auto; }
@media (max-width: 900px) {
  .admin-layout { flex-direction: column; }
  .sidebar { width: 100%; padding: 16px 20px 0; position: static; }
  .sidebar nav { flex-direction: row; flex-wrap: wrap; }
}

/* ---------- Pipeline grid (admin overview) ---------- */
.pipeline-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(120px, 1fr)); gap: 10px; }
.pipeline-cell {
  border: 1px solid var(--border); border-radius: 8px; padding: 12px; text-align: center;
  display: flex; flex-direction: column; gap: 4px; color: var(--text);
}
.pipeline-cell:hover { border-color: var(--primary); text-decoration: none; background: #f8faff; }
.p-count { font-size: 20px; font-weight: 700; color: var(--primary); }
.p-label { font-size: 12px; color: var(--muted); }

/* ---------- Affiliate link card ---------- */
.affiliate-card { border-left: 4px solid var(--primary); }
.affiliate-row { display: flex; gap: 8px; align-items: stretch; }
.affiliate-row input {
  flex: 1; padding: 10px 12px; border: 1px solid var(--border); border-radius: 8px;
  font-family: monospace; font-size: 13px; background: #f8faff; color: var(--text);
}
.affiliate-row .btn { white-space: nowrap; }

/* Locked referral banner on the student register form */
.locked-ref {
  display: flex; align-items: center; gap: 12px; margin-bottom: 16px;
  padding: 12px 16px; border: 1px solid var(--primary); border-radius: 8px;
  background: linear-gradient(180deg, #eff4ff, #fff);
}
.locked-ref .lock-icon { font-size: 22px; }

/* ---------- Viewer (read-only) badge in sidebar ---------- */
.viewer-badge {
  margin-top: 10px; padding: 6px 12px; border-radius: 8px; text-align: center;
  background: #fef3c7; color: #92400e; font-size: 12px; font-weight: 600;
  text-transform: uppercase; letter-spacing: .4px;
}

/* ---------- Page head with action button ---------- */
.page-head { display: flex; align-items: center; justify-content: space-between; gap: 12px; margin-bottom: 14px; flex-wrap: wrap; }
.page-head h2 { margin: 0; }

/* ---------- Filter chips ---------- */
.filter-row { display: flex; gap: 8px; flex-wrap: wrap; margin-bottom: 16px; }
.chip {
  padding: 5px 14px; border-radius: 999px; background: var(--card); border: 1px solid var(--border);
  font-size: 13px; color: var(--text);
}
.chip:hover { border-color: var(--primary); text-decoration: none; }
.chip.active { background: var(--primary); border-color: var(--primary); color: #fff; font-weight: 600; }