/* KietKey — trang giới thiệu */

:root {
  --bg: #0c0c0f;
  --bg-2: #141418;
  --card: #17171c;
  --line: rgba(255, 255, 255, 0.09);
  --line-soft: rgba(255, 255, 255, 0.055);
  --fg: #f2f2f5;
  --fg-2: #a3a3ad;
  --fg-3: #74747f;
  --accent: #5b8cff;
  --accent-soft: rgba(91, 140, 255, 0.14);
  --green: #32d158;
  --radius: 14px;
  --maxw: 1080px;
  --font: -apple-system, BlinkMacSystemFont, "SF Pro Text", "Segoe UI", system-ui, sans-serif;
}

@media (prefers-color-scheme: light) {
  :root {
    --bg: #fbfbfd;
    --bg-2: #f2f2f5;
    --card: #ffffff;
    --line: rgba(0, 0, 0, 0.11);
    --line-soft: rgba(0, 0, 0, 0.07);
    --fg: #16161a;
    --fg-2: #56565e;
    --fg-3: #85858f;
    --accent: #0a5fe0;
    --accent-soft: rgba(10, 95, 224, 0.1);
  }
}

* { box-sizing: border-box; }

html { scroll-behavior: smooth; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--fg);
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

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

kbd {
  font-family: var(--font);
  font-size: 0.85em;
  padding: 1px 6px;
  margin: 0 1px;
  border-radius: 5px;
  background: var(--bg-2);
  border: 1px solid var(--line);
  white-space: nowrap;
}

code {
  font-family: ui-monospace, SFMono-Regular, Menlo, monospace;
  font-size: 0.9em;
}

em { font-style: normal; color: var(--fg); font-weight: 500; }

/* ---------- thanh điều hướng ---------- */

.nav {
  position: sticky;
  top: 0;
  z-index: 50;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 12px 22px;
  background: color-mix(in srgb, var(--bg) 82%, transparent);
  backdrop-filter: saturate(180%) blur(16px);
  -webkit-backdrop-filter: saturate(180%) blur(16px);
  border-bottom: 1px solid var(--line-soft);
}

.brand {
  display: flex;
  align-items: center;
  gap: 9px;
  color: var(--fg);
  font-weight: 600;
  font-size: 16px;
}
.brand:hover { text-decoration: none; }
.brand img { border-radius: 6px; }

.nav nav { display: flex; gap: 20px; flex-wrap: wrap; }
.nav nav a { color: var(--fg-2); font-size: 14px; }
.nav nav a:hover { color: var(--fg); text-decoration: none; }

/* ---------- hero ---------- */

main { max-width: var(--maxw); margin: 0 auto; padding: 0 22px; }

.hero { padding: 88px 0 72px; text-align: center; }

.eyebrow {
  margin: 0 0 14px;
  font-size: 13px;
  font-weight: 600;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--fg-3);
}

h1 {
  margin: 0;
  font-size: clamp(38px, 6.5vw, 66px);
  line-height: 1.08;
  letter-spacing: -0.03em;
  font-weight: 700;
}

.accent {
  background: linear-gradient(100deg, var(--accent), #9b7bff);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.lede {
  max-width: 620px;
  margin: 24px auto 0;
  font-size: 17px;
  color: var(--fg-2);
}

.cta { display: flex; gap: 12px; justify-content: center; margin-top: 32px; flex-wrap: wrap; }

.btn {
  display: inline-block;
  padding: 11px 24px;
  border-radius: 10px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--fg);
  font-size: 15px;
  font-weight: 500;
  transition: transform 0.12s ease, border-color 0.12s ease;
}
.btn:hover { text-decoration: none; transform: translateY(-1px); border-color: var(--fg-3); }
.btn.primary { background: var(--accent); border-color: transparent; color: #fff; }
.btn.primary:hover { filter: brightness(1.08); }

.req { margin-top: 16px; font-size: 13.5px; color: var(--fg-3); }

/* ---------- HUD ---------- */

.hud-demo { margin-top: 68px; }

.hud {
  position: relative;
  width: 132px;
  height: 132px;
  margin: 0 auto;
  border-radius: 30px;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
  color: #fff;
  background: rgba(28, 22, 44, 0.62);
  border: 1px solid rgba(255, 255, 255, 0.26);
  box-shadow: 0 18px 44px rgba(10, 6, 24, 0.42), inset 0 1px 0 rgba(255, 255, 255, 0.36);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
}

/* Khung cắt và cột trượt PHẢI là hai element khác nhau: nếu để chung, chính
   khung bị dịch chuyển nên chữ nhảy lên rồi rơi lại chứ không bao giờ đổi. */
.hud-clip { height: 58px; overflow: hidden; }
.hud-clip .hud-slide {
  display: block;
  animation: hud-slide 7s cubic-bezier(0.62, 0.01, 0.2, 1) infinite;
}
.hud-slide span {
  display: flex;
  align-items: center;
  justify-content: center;
  height: 58px;
  font-size: 54px;
  font-weight: 600;
  line-height: 1;
}
.hud-caption { height: 17px; }
.hud-caption span { height: 17px; font-size: 12.5px; font-weight: 400; opacity: 0.92; }

@keyframes hud-slide {
  0%, 24%   { transform: translateY(0); }
  32%, 74%  { transform: translateY(-50%); }
  82%, 100% { transform: translateY(0); }
}

.hud-note { margin-top: 20px; font-size: 13.5px; color: var(--fg-3); text-align: center; }

/* ---------- tính năng ---------- */

section { padding: 64px 0; }

h2 {
  margin: 0 0 10px;
  font-size: clamp(26px, 3.4vw, 34px);
  letter-spacing: -0.02em;
  font-weight: 650;
}

.sub { margin: 0 0 32px; color: var(--fg-2); }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(290px, 1fr));
  gap: 18px;
  margin-top: 36px;
}

.card {
  padding: 24px;
  border-radius: var(--radius);
  background: var(--card);
  border: 1px solid var(--line-soft);
}

.card .icon {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--accent-soft);
  color: var(--accent);
  margin-bottom: 14px;
}
.card .icon svg { width: 20px; height: 20px; }

.card h3 { margin: 0 0 8px; font-size: 17px; font-weight: 600; }
.card p { margin: 0; font-size: 14.5px; color: var(--fg-2); }

/* ---------- cửa sổ minh hoạ ---------- */

.window {
  margin-top: 32px;
  border-radius: 13px;
  overflow: hidden;
  border: 1px solid var(--line);
  background: var(--bg-2);
  box-shadow: 0 28px 70px rgba(0, 0, 0, 0.42);
}

.titlebar {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 11px 14px;
  border-bottom: 1px solid var(--line-soft);
  background: color-mix(in srgb, var(--card) 70%, transparent);
}
.dot { width: 12px; height: 12px; border-radius: 50%; display: block; }
.dot.red { background: #ff5f57; }
.dot.yellow { background: #febc2e; }
.dot.green { background: #28c840; }
.titlebar .title { margin-left: 12px; font-size: 13px; color: var(--fg-2); font-weight: 500; }

.window-body { display: flex; min-height: 470px; }

.sidebar {
  width: 212px;
  flex: none;
  padding: 10px;
  border-right: 1px solid var(--line-soft);
  background: color-mix(in srgb, var(--card) 55%, transparent);
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.search {
  padding: 6px 10px;
  margin-bottom: 8px;
  border-radius: 7px;
  background: var(--bg-2);
  border: 1px solid var(--line-soft);
  font-size: 12.5px;
  color: var(--fg-3);
}

.nav-item {
  appearance: none;
  border: 0;
  background: transparent;
  color: var(--fg);
  font-family: inherit;
  font-size: 13px;
  text-align: left;
  padding: 8px 10px;
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.14s ease;
}
.nav-item:hover { background: var(--line-soft); }
.nav-item.is-active { background: var(--accent); color: #fff; font-weight: 500; }

.side-foot { margin-top: auto; padding: 10px; font-size: 11px; line-height: 1.5; color: var(--fg-3); }

.content { flex: 1; min-width: 0; padding: 20px 22px; overflow: hidden; }

.pane { display: none; }
.pane.is-shown { display: block; animation: rise 0.34s cubic-bezier(0.2, 0.7, 0.3, 1) both; }

@keyframes rise { from { opacity: 0; transform: translateY(8px); } to { opacity: 1; transform: none; } }

.status {
  display: flex;
  align-items: center;
  gap: 13px;
  padding: 13px 14px;
  border-radius: 12px;
  margin-bottom: 18px;
  background: linear-gradient(135deg, var(--accent-soft), transparent);
  border: 1px solid color-mix(in srgb, var(--accent) 34%, transparent);
}
.badge {
  width: 40px; height: 40px; flex: none;
  border-radius: 11px;
  background: var(--accent);
  color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: 17px; font-weight: 600;
}
.status-text { flex: 1; min-width: 0; display: flex; flex-direction: column; }
.status-text strong { font-size: 14px; font-weight: 600; }
.status-text small { font-size: 11.5px; color: var(--fg-2); }

h4 {
  margin: 20px 0 7px 4px;
  font-size: 11px;
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--fg-3);
}

.group {
  border-radius: 10px;
  border: 1px solid var(--line-soft);
  background: var(--card);
  overflow: hidden;
}

.row {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 9px 14px;
  min-height: 40px;
  font-size: 13px;
  border-top: 1px solid var(--line-soft);
}
.row:first-child { border-top: 0; }
/* Ô chữ có thể là con đầu, hoặc con thứ hai khi đứng sau nút radio — nên chọn
   theo "có chứa <small>" và theo "không phải điều khiển", thay vì theo vị trí. */
.row > span:has(small) { display: flex; flex-direction: column; gap: 2px; }
.row > span:not(.switch):not(.pill):not(.radio):not(.minus):not(.keys):not(.grow) {
  flex: 1;
  min-width: 0;
}
.row small { font-size: 11px; color: var(--fg-3); line-height: 1.35; }
.row .grow { flex: 1; }
.row.add { color: var(--accent); cursor: default; }

.pill {
  flex: none;
  font-size: 12.5px;
  padding: 3px 10px;
  border-radius: 7px;
  background: color-mix(in srgb, var(--fg) 10%, transparent);
  border: 1px solid var(--line);
  color: var(--fg);
}

.switch {
  flex: none;
  width: 40px; height: 24px;
  border-radius: 12px;
  background: var(--line);
  position: relative;
  display: block;
}
.switch::after {
  content: "";
  position: absolute;
  top: 2px; left: 2px;
  width: 20px; height: 20px;
  border-radius: 50%;
  background: #fff;
  box-shadow: 0 1px 2px rgba(0, 0, 0, 0.3);
  transition: left 0.16s ease;
}
.switch.on { background: var(--green); }
.switch.on::after { left: 18px; }

.radio {
  flex: none;
  width: 16px; height: 16px;
  border-radius: 50%;
  border: 1.5px solid var(--fg-3);
  display: block;
}
.radio.on { border: 5px solid var(--accent); }

.keys { flex-direction: row !important; gap: 4px; }
.minus { color: var(--fg-3); font-size: 16px; }

/* ---------- cài đặt ---------- */

.install-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 18px;
  margin: 32px 0 44px;
}

.step {
  padding: 22px;
  border-radius: var(--radius);
  background: var(--card);
  border: 1px solid var(--line-soft);
}
.step .num {
  display: inline-flex;
  align-items: center; justify-content: center;
  width: 26px; height: 26px;
  border-radius: 50%;
  background: var(--accent-soft);
  color: var(--accent);
  font-size: 13px; font-weight: 600;
  margin-bottom: 12px;
}
.step h3 { margin: 0 0 7px; font-size: 16px; font-weight: 600; }
.step p { margin: 0; font-size: 14.5px; color: var(--fg-2); }

.build-title { font-size: 18px; margin: 0 0 14px; font-weight: 600; }

pre {
  margin: 0;
  padding: 18px 20px;
  border-radius: var(--radius);
  background: var(--bg-2);
  border: 1px solid var(--line-soft);
  overflow-x: auto;
  font-size: 13.5px;
  line-height: 1.7;
}

.note { margin-top: 14px; font-size: 14px; color: var(--fg-2); }

/* ---------- riêng tư ---------- */

.privacy { max-width: 720px; }
.privacy p { color: var(--fg-2); font-size: 15.5px; }
.privacy strong { color: var(--fg); }

/* ---------- chân trang ---------- */

footer { border-top: 1px solid var(--line-soft); margin-top: 40px; }
.foot-inner { max-width: var(--maxw); margin: 0 auto; padding: 32px 22px 48px; }
footer p { margin: 0 0 8px; font-size: 14px; color: var(--fg-2); }
footer .muted { color: var(--fg-3); }

/* ---------- màn hình hẹp ---------- */

@media (max-width: 720px) {
  .window-body { flex-direction: column; min-height: 0; }
  .sidebar {
    width: auto;
    flex-direction: row;
    overflow-x: auto;
    border-right: 0;
    border-bottom: 1px solid var(--line-soft);
  }
  .search, .side-foot { display: none; }
  .nav-item { white-space: nowrap; }
  .hero { padding: 56px 0 48px; }
  section { padding: 48px 0; }
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  .hud-clip .hud-slide, .pane.is-shown { animation: none; }
}