/* chuyencuabach.com — minimal tech */
:root {
  --bg: #ffffff;
  --bg-soft: #f6f7f9;
  --text: #111827;
  --muted: #5b6475;
  --line: #e5e7eb;
  --accent: #c8102e;
  --accent-soft: #fdecee;
  --navy: #1f2a44;
  --radius: 14px;
  --max: 1080px;
  --mono: ui-monospace, "Cascadia Code", Consolas, monospace;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0c1222;
    --bg-soft: #141c30;
    --text: #e8ecf4;
    --muted: #97a1b6;
    --line: #232d45;
    --accent: #ff4d5e;
    --accent-soft: #2a1820;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0c1222;
  --bg-soft: #141c30;
  --text: #e8ecf4;
  --muted: #97a1b6;
  --line: #232d45;
  --accent: #ff4d5e;
  --accent-soft: #2a1820;
  color-scheme: dark;
}

* { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }
body {
  font-family: "Be Vietnam Pro", system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--bg);
  color: var(--text);
  line-height: 1.65;
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}
a { color: inherit; text-decoration: none; }
img { max-width: 100%; display: block; }
.wrap { max-width: var(--max); margin: 0 auto; padding: 0 20px; }

/* ---------- header ---------- */
.site-header {
  position: sticky; top: 0; z-index: 10;
  background: color-mix(in srgb, var(--bg) 88%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--line);
}
.nav { display: flex; align-items: center; justify-content: space-between; height: 64px; }
.brand { font-weight: 700; font-size: 18px; letter-spacing: -0.01em; }
.brand span { color: var(--accent); }
.brand small { font-family: var(--mono); font-weight: 400; color: var(--muted); font-size: 13px; }
.menu { display: flex; gap: 28px; align-items: center; list-style: none; }
.menu a { color: var(--muted); font-size: 15px; transition: color .15s; }
.menu a:hover, .menu a[aria-current="page"] { color: var(--text); }
.menu a[aria-current="page"] { font-weight: 600; }
.icon-btn {
  background: none; border: 1px solid var(--line); color: var(--text);
  width: 36px; height: 36px; border-radius: 10px; cursor: pointer; font-size: 16px;
}
.menu-toggle { display: none; }

/* ---------- buttons ---------- */
.btn {
  display: inline-flex; align-items: center; gap: 8px;
  padding: 12px 22px; border-radius: 10px; font-weight: 600; font-size: 15px;
  border: 1px solid transparent; cursor: pointer; transition: transform .15s, background .15s;
}
.btn:hover { transform: translateY(-1px); }
.btn-primary { background: var(--accent); color: #fff; }
.btn-ghost { border-color: var(--line); color: var(--text); }
.btn-ghost:hover { background: var(--bg-soft); }

/* ---------- hero ---------- */
.hero { padding: 96px 0 72px; position: relative; overflow: hidden; }
.hero::before {
  content: ""; position: absolute; inset: 0; z-index: -1;
  background-image:
    linear-gradient(var(--line) 1px, transparent 1px),
    linear-gradient(90deg, var(--line) 1px, transparent 1px);
  background-size: 48px 48px;
  mask-image: radial-gradient(ellipse 70% 60% at 70% 30%, #000 20%, transparent 75%);
  opacity: .6;
}
.tag {
  display: inline-block; font-family: var(--mono); font-size: 13px; color: var(--accent);
  background: var(--accent-soft); padding: 4px 12px; border-radius: 999px; margin-bottom: 20px;
}
h1 { font-size: clamp(34px, 6vw, 58px); line-height: 1.12; letter-spacing: -0.03em; font-weight: 800; max-width: 16ch; }
h1 em { font-style: normal; color: var(--accent); }
.lead { font-size: clamp(17px, 2.2vw, 19px); color: var(--muted); max-width: 58ch; margin: 22px 0 34px; }
.actions { display: flex; gap: 12px; flex-wrap: wrap; }

/* ---------- sections ---------- */
section { padding: 72px 0; }
.section-soft { background: var(--bg-soft); border-block: 1px solid var(--line); }
.eyebrow { font-family: var(--mono); font-size: 13px; color: var(--accent); margin-bottom: 10px; }
h2 { font-size: clamp(26px, 4vw, 36px); letter-spacing: -0.02em; line-height: 1.2; margin-bottom: 14px; }
h3 { font-size: 18px; margin-bottom: 8px; }
.sub { color: var(--muted); max-width: 60ch; margin-bottom: 40px; }

.grid { display: grid; gap: 18px; grid-template-columns: repeat(3, 1fr); }
.card {
  background: var(--bg); border: 1px solid var(--line); border-radius: var(--radius);
  padding: 26px; transition: border-color .15s, transform .15s;
}
.card:hover { border-color: var(--accent); transform: translateY(-2px); }
.card p { color: var(--muted); font-size: 15px; }
.card .ico {
  width: 42px; height: 42px; border-radius: 10px; display: grid; place-items: center;
  background: var(--accent-soft); color: var(--accent); margin-bottom: 18px;
}
.card .ico svg { width: 22px; height: 22px; }
.card ul { margin-top: 14px; padding-left: 18px; color: var(--muted); font-size: 14px; }
.card ul li { margin: 4px 0; }
.more { display: inline-block; margin-top: 14px; font-size: 14px; font-weight: 600; color: var(--accent); }

.steps { display: grid; grid-template-columns: repeat(4, 1fr); gap: 18px; counter-reset: s; }
.step { border-top: 2px solid var(--line); padding-top: 18px; }
.step::before {
  counter-increment: s; content: "0" counter(s);
  font-family: var(--mono); color: var(--accent); font-size: 14px; display: block; margin-bottom: 6px;
}
.step p { color: var(--muted); font-size: 15px; }

.cta {
  background: var(--navy); color: #fff; border-radius: 20px; padding: 48px;
  display: flex; justify-content: space-between; align-items: center; gap: 24px; flex-wrap: wrap;
}
.cta h2 { margin: 0; }
.cta p { color: #b9c2d6; margin-top: 6px; }

/* ---------- page header ---------- */
.page-head { padding: 72px 0 24px; }
.page-head h1 { font-size: clamp(30px, 5vw, 46px); max-width: none; }

/* ---------- service detail ---------- */
.service { display: grid; grid-template-columns: 1fr 1.4fr; gap: 40px; padding: 40px 0; border-bottom: 1px solid var(--line); }
.service:last-child { border-bottom: 0; }
.service .num { font-family: var(--mono); color: var(--accent); font-size: 14px; }
.service h2 { font-size: 26px; }
.service p { color: var(--muted); }
.checks { list-style: none; display: grid; gap: 10px; margin-top: 4px; }
.checks li { padding-left: 28px; position: relative; }
.checks li::before {
  content: "✓"; position: absolute; left: 0; top: 0; color: var(--accent); font-weight: 700;
}

/* ---------- contact ---------- */
.contact { display: grid; grid-template-columns: 1fr 1.3fr; gap: 40px; }
.info-list { list-style: none; display: grid; gap: 22px; align-content: start; }
.info-list li { display: flex; gap: 14px; align-items: flex-start; }
.info-list .ico { flex: none; width: 40px; height: 40px; border-radius: 10px; background: var(--accent-soft); color: var(--accent); display: grid; place-items: center; }
.info-list .ico svg { width: 20px; height: 20px; }
.info-list small { color: var(--muted); display: block; font-size: 13px; }
form { display: grid; gap: 14px; }
label { font-size: 14px; font-weight: 600; display: grid; gap: 6px; }
input, select, textarea {
  font: inherit; font-weight: 400; color: var(--text); background: var(--bg);
  border: 1px solid var(--line); border-radius: 10px; padding: 12px 14px; width: 100%;
}
input:focus, select:focus, textarea:focus { outline: 2px solid var(--accent); outline-offset: -1px; border-color: transparent; }
textarea { min-height: 130px; resize: vertical; }
.row2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
.note { font-size: 13px; color: var(--muted); }

/* ---------- policy ---------- */
.prose { max-width: 760px; padding-bottom: 72px; }
.prose h2 { font-size: 22px; margin: 36px 0 10px; }
.prose p, .prose li { color: var(--muted); }
.prose ul { padding-left: 22px; margin: 8px 0; }
.prose li { margin: 4px 0; }
.toc { background: var(--bg-soft); border: 1px solid var(--line); border-radius: var(--radius); padding: 18px 22px; margin: 8px 0 12px; }
.toc a { color: var(--accent); }
.toc ol { padding-left: 20px; }

/* ---------- footer ---------- */
.site-footer { border-top: 1px solid var(--line); padding: 36px 0; color: var(--muted); font-size: 14px; }
.foot { display: flex; justify-content: space-between; gap: 20px; flex-wrap: wrap; }
.foot nav { display: flex; gap: 20px; flex-wrap: wrap; }
.foot a:hover { color: var(--text); }

/* ---------- responsive ---------- */
@media (max-width: 860px) {
  .grid { grid-template-columns: 1fr 1fr; }
  .steps { grid-template-columns: 1fr 1fr; }
  .service, .contact { grid-template-columns: 1fr; gap: 18px; }
}
@media (max-width: 640px) {
  .wrap { padding: 0 16px; }
  .menu-toggle { display: inline-block; }
  .menu {
    display: none; position: absolute; top: 64px; left: 0; right: 0;
    flex-direction: column; align-items: stretch; gap: 0;
    background: var(--bg); border-bottom: 1px solid var(--line); padding: 8px 16px 16px;
  }
  .menu.open { display: flex; }
  .menu li a { display: block; padding: 12px 0; border-bottom: 1px solid var(--line); }
  .menu li:last-child { padding-top: 12px; }
  .grid, .steps, .row2 { grid-template-columns: 1fr; }
  .hero { padding: 64px 0 48px; }
  section { padding: 56px 0; }
  .cta { padding: 32px 24px; }
}