/* Koder Talk landing — light/dark/device theming via CSS variables. */

:root {
  color-scheme: light;
  --bg:        #ffffff;
  --bg-alt:    #f8fafc;
  --bg-card:   #ffffff;
  --fg:        #0f172a;
  --fg-muted:  #475569;
  --border:    #e2e8f0;
  --accent:    #8B5CF6;
  --accent-2:  #6D28D9;
  --accent-fg: #ffffff;
  --shadow:    0 1px 2px rgba(15,23,42,0.04), 0 8px 24px rgba(15,23,42,0.06);
}

:root[data-theme="dark"] {
  color-scheme: dark;
  --bg:        #0b1020;
  --bg-alt:    #11162a;
  --bg-card:   #161b33;
  --fg:        #f1f5f9;
  --fg-muted:  #94a3b8;
  --border:    #1f2540;
  --accent:    #A78BFA;
  --accent-2:  #8B5CF6;
  --accent-fg: #0b1020;
  --shadow:    0 1px 2px rgba(0,0,0,0.4), 0 8px 24px rgba(0,0,0,0.4);
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]):not([data-theme="dark"]) {
    color-scheme: dark;
    --bg:        #0b1020;
    --bg-alt:    #11162a;
    --bg-card:   #161b33;
    --fg:        #f1f5f9;
    --fg-muted:  #94a3b8;
    --border:    #1f2540;
    --accent:    #A78BFA;
    --accent-2:  #8B5CF6;
    --accent-fg: #0b1020;
    --shadow:    0 1px 2px rgba(0,0,0,0.4), 0 8px 24px rgba(0,0,0,0.4);
  }
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}

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

img { display: block; max-width: 100%; }

/* ----- Nav ----- */
.nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 1rem 2rem;
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  background: color-mix(in srgb, var(--bg) 85%, transparent);
  backdrop-filter: blur(12px);
  z-index: 10;
}
.brand {
  display: inline-flex;
  align-items: center;
  gap: 0.6rem;
  font-weight: 700;
  font-size: 1.1rem;
  color: var(--fg);
}
.nav-links {
  display: flex;
  gap: 1.5rem;
}
.nav-links a {
  color: var(--fg-muted);
  font-weight: 500;
}
.nav-actions {
  display: flex;
  align-items: center;
  gap: 0.75rem;
}
#theme-toggle {
  background: transparent;
  color: var(--fg-muted);
  border: 1px solid var(--border);
  border-radius: 0.5rem;
  width: 38px;
  height: 38px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
}
#theme-toggle:hover { color: var(--fg); border-color: var(--accent); }
#theme-toggle svg { display: none; }
:root[data-theme-mode="light"]  #theme-toggle .i-sun     { display: block; }
:root[data-theme-mode="dark"]   #theme-toggle .i-moon    { display: block; }
:root[data-theme-mode="device"] #theme-toggle .i-monitor { display: block; }

.cta {
  display: inline-block;
  padding: 0.55rem 1.1rem;
  border-radius: 0.5rem;
  font-weight: 600;
  border: 1px solid var(--border);
  color: var(--fg);
}
.cta:hover { text-decoration: none; border-color: var(--accent); }
.cta-primary {
  background: var(--accent);
  color: var(--accent-fg);
  border-color: var(--accent);
}
.cta-primary:hover { background: var(--accent-2); border-color: var(--accent-2); }
.cta-ghost { background: transparent; }

/* ----- Hero ----- */
.hero {
  display: grid;
  grid-template-columns: 1.2fr 1fr;
  gap: 3rem;
  align-items: center;
  max-width: 1100px;
  margin: 0 auto;
  padding: 5rem 2rem 4rem;
}
.hero h1 {
  font-size: clamp(2.2rem, 5vw, 3.5rem);
  line-height: 1.1;
  letter-spacing: -0.02em;
  margin: 0 0 1rem;
}
.lede {
  font-size: 1.15rem;
  color: var(--fg-muted);
  margin: 0 0 1.5rem;
  max-width: 36rem;
}
.hero-actions { display: flex; gap: 0.75rem; flex-wrap: wrap; }
.hero-meta { font-size: 0.85rem; color: var(--fg-muted); margin-top: 1.25rem; }
.hero-art { display: flex; justify-content: center; }
.hero-art img {
  width: min(320px, 80%);
  filter: drop-shadow(0 24px 48px rgba(139, 92, 246, 0.35));
  animation: float 6s ease-in-out infinite;
}
@keyframes float {
  0%, 100% { transform: translateY(0); }
  50%      { transform: translateY(-8px); }
}

@media (max-width: 760px) {
  .hero { grid-template-columns: 1fr; padding: 3rem 1.25rem; gap: 2rem; }
  .nav-links { display: none; }
}

/* ----- Sections ----- */
.section {
  max-width: 1100px;
  margin: 0 auto;
  padding: 4rem 2rem;
}
.section h2 {
  font-size: clamp(1.6rem, 3vw, 2.2rem);
  margin: 0 0 0.5rem;
  letter-spacing: -0.01em;
}
.section .lede { margin-bottom: 2rem; }

.grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(260px, 1fr));
  gap: 1rem;
  margin-top: 2rem;
}
.card {
  background: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 0.75rem;
  padding: 1.25rem 1.25rem 1rem;
  box-shadow: var(--shadow);
}
.card h3 {
  margin: 0 0 0.4rem;
  font-size: 1.1rem;
  color: var(--accent);
}
.card p { margin: 0; color: var(--fg-muted); }

/* ----- Privacy ----- */
.privacy { background: var(--bg-alt); border-top: 1px solid var(--border); border-bottom: 1px solid var(--border); max-width: none; padding-left: 0; padding-right: 0; }
.privacy > * { max-width: 1100px; margin-left: auto; margin-right: auto; padding-left: 2rem; padding-right: 2rem; }
.checklist { list-style: none; padding: 0; margin: 1.5rem auto 0; max-width: 1100px; padding-left: 2rem; padding-right: 2rem; }
.checklist li {
  position: relative;
  padding: 0.6rem 0 0.6rem 1.75rem;
  color: var(--fg-muted);
  border-bottom: 1px solid var(--border);
}
.checklist li::before {
  content: "✓";
  position: absolute;
  left: 0;
  top: 0.6rem;
  color: var(--accent);
  font-weight: 700;
}
.checklist li strong { color: var(--fg); }

/* ----- Downloads ----- */
.downloads {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(220px, 1fr));
  gap: 0.75rem;
  margin-top: 1.5rem;
}
.dl {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.85rem 1rem;
  border: 1px solid var(--border);
  border-radius: 0.6rem;
  background: var(--bg-card);
  color: var(--fg);
  box-shadow: var(--shadow);
}
.dl:hover { border-color: var(--accent); text-decoration: none; }
.dl-icon { font-size: 1.4rem; }
.dl-name { font-weight: 600; }
.dl-meta { color: var(--fg-muted); font-size: 0.85rem; margin-left: auto; }

/* ----- Footer ----- */
footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--border);
  padding: 3rem 2rem 2rem;
}
.foot-grid {
  display: grid;
  grid-template-columns: 1.4fr repeat(3, 1fr);
  gap: 2rem;
  max-width: 1100px;
  margin: 0 auto;
}
.foot-grid h4 { margin: 0 0 0.6rem; font-size: 0.9rem; text-transform: uppercase; letter-spacing: 0.05em; color: var(--fg-muted); }
.foot-grid ul { list-style: none; padding: 0; margin: 0; }
.foot-grid li { padding: 0.25rem 0; }
.foot-grid a { color: var(--fg-muted); }
.foot-grid a:hover { color: var(--accent); }
.muted { color: var(--fg-muted); margin-top: 0.5rem; }
.copy { text-align: center; color: var(--fg-muted); font-size: 0.85rem; margin-top: 2rem; }

@media (max-width: 760px) {
  .foot-grid { grid-template-columns: 1fr 1fr; }
}