:root {
  color-scheme: dark;
  --bg: #0c0d10;
  --surface: #15171c;
  --border: #2a2d36;
  --text: #e8eaef;
  --muted: #9aa3b2;
  --accent: #f6821f;
  --accent-hover: #ff9a3c;
  --btn-fg: #111;
  --ok: #7dd87d;
  --err: #f87171;
  --radius: 10px;
  --font: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  --header-h: 4rem;
}

@media (prefers-color-scheme: light) {
  :root {
    color-scheme: light;
    --bg: #f6f7f9;
    --surface: #ffffff;
    --border: #d9dde3;
    --text: #14151a;
    --muted: #5c6370;
    --accent: #e35f00;
    --accent-hover: #ff7a1a;
    --btn-fg: #fff;
    --ok: #1d7a32;
    --err: #c62828;
  }
}

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: var(--font);
  background: var(--bg);
  color: var(--text);
  line-height: 1.55;
}

.site-header {
  position: sticky;
  top: 0;
  z-index: 10;
  background: color-mix(in srgb, var(--bg) 92%, transparent);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
}

.site-header__inner {
  max-width: 960px;
  margin: 0 auto;
  padding: 0.85rem 1.5rem;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
  min-height: var(--header-h);
}

.brand {
  font-size: 1.35rem;
  font-weight: 750;
  letter-spacing: 0.14em;
  color: var(--text);
  text-decoration: none;
}

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

.signup-form--header {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  align-items: center;
  justify-content: flex-end;
}

.signup-form--header input {
  flex: 1 1 160px;
  min-width: 0;
  max-width: 220px;
  padding: 0.5rem 0.65rem;
  border-radius: 8px;
  border: 1px solid var(--border);
  background: var(--surface);
  color: var(--text);
  font: inherit;
  font-size: 0.9rem;
}

.signup-form--header input:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.signup-form--header button {
  padding: 0.5rem 1rem;
  border: none;
  border-radius: 8px;
  background: var(--accent);
  color: var(--btn-fg);
  font: inherit;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  white-space: nowrap;
}

.signup-form--header button:hover {
  background: var(--accent-hover);
}

.signup-form--header button:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.site-header .form-message {
  max-width: 960px;
  margin: 0 auto;
  padding: 0 1.5rem 0.65rem;
  font-size: 0.85rem;
  min-height: 0;
}

.site-header .form-message.ok {
  color: var(--ok);
}

.site-header .form-message.err {
  color: var(--err);
}

main {
  flex: 1;
  width: 100%;
  max-width: 960px;
  margin: 0 auto;
  padding: 2rem 1.5rem 2.5rem;
}

.video-stage {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.videos {
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
}

.video-card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow: hidden;
}

.video-card iframe {
  display: block;
  width: 100%;
  aspect-ratio: 16 / 9;
  border: 0;
}

.placeholder,
.empty-hint {
  color: var(--muted);
  margin: 0;
  padding: 1.25rem 0;
  font-size: 0.95rem;
}

.video-about {
  padding-top: 0.25rem;
  border-top: 1px solid var(--border);
}

.video-about__title {
  margin: 0 0 0.75rem;
  font-size: 1.05rem;
  font-weight: 650;
  letter-spacing: -0.02em;
  color: var(--text);
}

.video-about p {
  margin: 0 0 1rem;
  color: var(--muted);
  font-size: 0.95rem;
  max-width: 65ch;
}

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

.site-footer {
  margin-top: auto;
  padding: 1.5rem 1.5rem 2rem;
  border-top: 1px solid var(--border);
  text-align: center;
}

.site-footer p {
  margin: 0;
  font-size: 0.8rem;
  color: var(--muted);
  letter-spacing: 0.02em;
}

.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}