:root {
  --bg: #0a0a0a;
  --bg-header: rgba(10, 10, 10, 0.92);
  --text: #ffffff;
  --text-muted: #b0b0b0;
  --text-dim: #888888;
  --line: #2a2a2a;
  --blue: #2563eb;
  --blue-hover: #1d4ed8;
  --blue-active: #1e40af;
  --accent: #5eb8ff;
  --font: "Segoe UI", "Malgun Gothic", sans-serif;
  --header-h: 70px;
  --max: 1080px;
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 16px;
  line-height: 1.5;
  color: var(--text);
  background: var(--bg);
}

a {
  color: var(--text-muted);
  text-decoration: none;
}

a:hover {
  color: var(--text);
}

.site-header {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  height: var(--header-h);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  padding: 4px clamp(16px, 4vw, 40px);
  background: var(--bg-header);
  border-bottom: 1px solid var(--line);
  backdrop-filter: blur(8px);
}

.brand {
  margin: 0;
  padding: 0;
  border: none;
  background: transparent;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  line-height: 0;
}

.brand img {
  display: block;
  height: clamp(44px, 7vw, 52px);
  width: auto;
}

.nav {
  display: flex;
  align-items: center;
  justify-content: flex-end;
  flex-wrap: wrap;
  gap: 8px 20px;
  margin-left: auto;
}

.nav-link {
  display: inline-flex;
  align-items: center;
  padding: 8px 4px;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  color: var(--text-muted);
  background: transparent;
  border: none;
  border-bottom: 2px solid transparent;
  cursor: pointer;
  text-decoration: none;
}

.nav-link:hover {
  color: var(--text);
}

.nav-link.active {
  color: var(--text);
  border-bottom-color: var(--blue);
}

.btn-download {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 8px 20px;
  font: inherit;
  font-size: 0.95rem;
  font-weight: 600;
  color: #fff;
  background: var(--blue);
  border: none;
  border-radius: 7px;
  cursor: pointer;
  text-decoration: none;
  transition: background-color 0.15s ease, transform 0.1s ease;
}

.btn-download:hover {
  background: var(--blue-hover);
  color: #fff;
}

.btn-download:active {
  background: var(--blue-active);
  transform: scale(0.98);
}

.btn-download--lg {
  padding: 12px 35px;
  font-size: 1.1rem;
  font-weight: 700;
  border-radius: 9px;
}

.main {
  padding-top: var(--header-h);
}

.tab-pane {
  display: none;
}

.tab-pane.active {
  display: block;
}

.hero {
  position: relative;
  min-height: calc(100vh - var(--header-h));
  display: flex;
  align-items: center;
  justify-content: flex-end;
  text-align: right;
  padding: clamp(48px, 10vh, 96px) clamp(24px, 6vw, 72px) clamp(48px, 10vh, 96px) clamp(16px, 4vw, 40px);
  overflow: hidden;
}

.hero-bg {
  position: absolute;
  inset: 0;
  background-color: #050505;
  background-image: url("https://assets.kbondwatcher.com/brand/background.png");
  background-size: cover;
  background-position: center;
  background-repeat: no-repeat;
}

.hero-inner {
  position: relative;
  z-index: 1;
  max-width: 800px;
  display: flex;
  flex-direction: column;
  align-items: flex-end;
}

.hero-title {
  margin: 0 0 16px;
  font-size: clamp(1.75rem, 5vw, 3.15rem);
  font-weight: 800;
  line-height: 1.2;
  letter-spacing: -0.02em;
}

.hero-sub {
  margin: 0 0 28px;
  font-size: clamp(1rem, 2.2vw, 1.2rem);
  color: var(--text-muted);
  max-width: 36em;
}

.videos {
  max-width: var(--max);
  margin: 0 auto;
  padding: clamp(80px, 14vw, 140px) clamp(16px, 4vw, 40px);
  display: flex;
  flex-direction: column;
  gap: clamp(72px, 12vw, 120px);
}

.video-block {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 20px;
}

.video-title {
  margin: 0;
  text-align: center;
  font-size: clamp(1.35rem, 3.2vw, 2rem);
  font-weight: 550;
  line-height: 1.35;
}

.accent {
  color: var(--accent);
}

.videos video {
  display: block;
  width: 100%;
  height: auto;
  border-radius: 12px;
  background: #111;
  pointer-events: none;
}

.about {
  max-width: 720px;
  margin: 0 auto;
  padding: clamp(48px, 10vw, 96px) clamp(16px, 4vw, 40px);
}

.about-block {
  margin: 0 0 clamp(36px, 6vw, 56px);
}

.about-block:last-child {
  margin-bottom: 0;
}

.about h2 {
  margin: 0 0 16px;
  font-size: clamp(1.5rem, 3vw, 2rem);
  font-weight: 700;
}

.about p {
  margin: 0 0 12px;
  color: var(--text-muted);
  font-size: 1.05rem;
  line-height: 1.6;
}

.about-list,
.about-steps {
  margin: 0;
  padding-left: 1.25rem;
  color: var(--text-muted);
  font-size: 1.05rem;
  line-height: 1.65;
}

.about-list li,
.about-steps li {
  margin: 0 0 12px;
}

.about-list li:last-child,
.about-steps li:last-child {
  margin-bottom: 0;
}

.about-list strong,
.about-steps strong {
  color: var(--text);
  font-weight: 700;
}

.about-steps p {
  margin: 6px 0 0;
}

.about code {
  font-family: ui-monospace, "Cascadia Mono", Consolas, monospace;
  font-size: 0.92em;
  color: var(--accent);
}

.site-footer {
  max-width: 720px;
  margin: 0 auto;
  padding: 48px clamp(16px, 4vw, 40px) 56px;
  text-align: center;
  font-size: 12px;
  color: var(--text-dim);
  line-height: 1.7;
}

.site-footer .footer-copy {
  margin: 0 0 12px;
}

.site-footer .footer-links {
  margin: 0 0 16px;
}

.site-footer .footer-links a {
  color: var(--text-muted);
}

.site-footer .footer-links a:hover {
  color: var(--text);
  text-decoration: underline;
}

.site-footer .footer-sep {
  margin: 0 8px;
  color: var(--line);
}

.site-footer .footer-disclaimer {
  margin: 0;
  color: var(--text-dim);
}

.licenses-page {
  max-width: 720px;
  margin: 0 auto;
  padding: 40px clamp(16px, 4vw, 40px) 64px;
}

.licenses-page .lead {
  color: var(--text-muted);
  margin: 0 0 24px;
}

.licenses-page table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.9rem;
}

.licenses-page th,
.licenses-page td {
  text-align: left;
  padding: 10px 8px;
  border-bottom: 1px solid var(--line);
  color: var(--text-muted);
}

.licenses-page th {
  color: var(--text);
  font-weight: 600;
}

@media (max-width: 640px) {
  :root {
    --header-h: 60px;
  }

  .nav {
    gap: 6px 12px;
  }

  .nav-link {
    font-size: 0.85rem;
  }

  .btn-download {
    padding: 8px 14px;
    font-size: 0.85rem;
  }

  .hero {
    min-height: calc(100vh - var(--header-h));
    align-items: center;
  }
}