:root {
  --primary: #2980B9;
  --primary-dark: #1f6391;
  --text: #1f2937;
  --muted: #5b6573;
  --bg: #f7f9fc;
  --card: #ffffff;
  --border: #e3e8ef;
  --ktest: #16a085;
  --ktkb: #8e44ad;
  --radius: 14px;
}

* { box-sizing: border-box; }

html { -webkit-text-size-adjust: 100%; }

body {
  margin: 0;
  font-family: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  font-size: 16px;
  line-height: 1.65;
  color: var(--text);
  background: var(--bg);
}

a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }

img { max-width: 100%; height: auto; }

.wrap { max-width: 1040px; margin: 0 auto; padding: 0 16px; }

/* ---------- Header ---------- */
.site-header {
  background: var(--card);
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 10;
}
.site-header .wrap {
  display: flex;
  align-items: center;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 8px 24px;
  min-height: 64px;
  padding-top: 8px;
  padding-bottom: 8px;
}
.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 700;
  font-size: 18px;
  color: var(--text);
}
.brand:hover { text-decoration: none; }
.brand-badge {
  width: 34px;
  height: 34px;
  border-radius: 9px;
  background: var(--primary);
  color: #fff;
  display: grid;
  place-items: center;
  font-size: 18px;
}
.nav { display: flex; flex-wrap: wrap; gap: 4px 18px; font-size: 15px; }
.nav a { color: var(--muted); font-weight: 500; }
.nav a:hover, .nav a[aria-current="page"] { color: var(--primary); text-decoration: none; }

/* ---------- Hero ---------- */
.hero {
  background: linear-gradient(135deg, #2980B9 0%, #1f6391 100%);
  color: #fff;
  padding: 56px 0 64px;
}
.hero h1 {
  font-size: clamp(28px, 5vw, 42px);
  line-height: 1.25;
  margin: 0 0 16px;
  max-width: 640px;
}
.hero p { font-size: 18px; max-width: 680px; margin: 0 0 28px; opacity: .95; }
.hero .btns { display: flex; flex-wrap: wrap; gap: 12px; }

.btn {
  display: inline-block;
  padding: 11px 22px;
  border-radius: 10px;
  font-weight: 600;
  font-size: 15px;
  border: 2px solid transparent;
}
.btn:hover { text-decoration: none; }
.btn-light { background: #fff; color: var(--primary-dark); }
.btn-light:hover { background: #eef5fb; }
.btn-ghost { border-color: rgba(255,255,255,.7); color: #fff; }
.btn-ghost:hover { background: rgba(255,255,255,.12); }
.btn-primary { background: var(--primary); color: #fff; }
.btn-primary:hover { background: var(--primary-dark); }
.btn-outline { border-color: var(--primary); color: var(--primary); }
.btn-outline:hover { background: #eef5fb; }
.btn-row { display: flex; flex-wrap: wrap; gap: 12px; margin: 0 0 8px; }

/* ---------- Sections ---------- */
section { padding: 48px 0; }
.section-title { font-size: clamp(22px, 3.5vw, 30px); margin: 0 0 8px; line-height: 1.3; }
.section-lead { color: var(--muted); margin: 0 0 28px; max-width: 720px; }

.cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 20px;
}
.card {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 24px;
  display: flex;
  flex-direction: column;
}
.card-head { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.card-icon {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  flex: none;
  display: grid;
  place-items: center;
  color: #fff;
  font-weight: 700;
  font-size: 20px;
}
.card-icon img { width: 48px; height: 48px; border-radius: 12px; }
.card h3 { margin: 0; font-size: 20px; }
.card .tag { font-size: 13px; color: var(--muted); }
.card p { margin: 0 0 12px; }
.card ul { margin: 0 0 16px; padding-left: 20px; color: var(--muted); }
.card ul li { margin-bottom: 4px; }
.card .links { margin-top: auto; display: flex; flex-wrap: wrap; gap: 8px 16px; font-weight: 600; font-size: 15px; }

.bg-ktest { background: var(--ktest); }
.bg-ktkb { background: var(--ktkb); }

.panel {
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 28px;
}

/* ---------- Article pages ---------- */
.page-head { background: var(--card); border-bottom: 1px solid var(--border); padding: 40px 0 32px; }
.page-head h1 { margin: 0 0 8px; font-size: clamp(26px, 4.5vw, 36px); line-height: 1.3; }
.page-head p { margin: 0; color: var(--muted); max-width: 720px; }

.article > * { max-width: 760px; }
.article h2 { font-size: 22px; margin: 36px 0 10px; line-height: 1.35; }
.article h3 { font-size: 18px; margin: 24px 0 8px; }
.article p, .article li { color: #333d4a; }
.article ul, .article ol { padding-left: 22px; }
.article li { margin-bottom: 6px; }
.article a { overflow-wrap: anywhere; }

.table-wrap { overflow-x: auto; }
table { border-collapse: collapse; width: 100%; background: var(--card); font-size: 15px; }
th, td { border: 1px solid var(--border); padding: 10px 12px; text-align: left; vertical-align: top; }
th { background: #eef3f8; }

.note {
  background: #eef5fb;
  border-left: 4px solid var(--primary);
  padding: 14px 18px;
  border-radius: 8px;
  margin: 20px 0;
}

.contact-list { list-style: none; padding: 0; margin: 0; }
.contact-list li { padding: 12px 0; border-bottom: 1px solid var(--border); }
.contact-list li:last-child { border-bottom: 0; }
.contact-list strong { display: inline-block; min-width: 110px; }

/* ---------- Footer ---------- */
.site-footer {
  background: #1f2937;
  color: #cbd2dc;
  padding: 32px 0;
  font-size: 15px;
  margin-top: 24px;
}
.site-footer .wrap { display: flex; flex-wrap: wrap; justify-content: space-between; gap: 12px 24px; }
.site-footer a { color: #fff; }
.site-footer nav { display: flex; flex-wrap: wrap; gap: 6px 18px; }

@media (max-width: 600px) {
  .site-header { position: static; }
  .hero { padding: 40px 0 44px; }
  .hero p { font-size: 16px; }
  section { padding: 36px 0; }
  .panel { padding: 20px; }
  .card { padding: 20px; }
}