:root {
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #5a5f66;
  --border: #e3e5e8;
  --accent: #7a1f2b;
  --card-bg: #fafafa;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #121212;
    --fg: #ececec;
    --muted: #a3a7ac;
    --border: #2b2d31;
    --accent: #d98a94;
    --card-bg: #1a1a1a;
  }
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--bg);
  color: var(--fg);
  line-height: 1.5;
}

header {
  max-width: 860px;
  margin: 0 auto;
  padding: 3rem 1.5rem 1.5rem;
}

header h1 {
  margin: 0 0 0.25rem;
  font-size: 1.9rem;
}

header p {
  margin: 0.15rem 0;
  color: var(--muted);
}

main {
  max-width: 860px;
  margin: 0 auto;
  padding: 1rem 1.5rem 4rem;
}

h2.section-title {
  font-size: 1.1rem;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
  padding-bottom: 0.5rem;
  margin-top: 2.5rem;
}

.talk {
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card-bg);
  padding: 1.25rem 1.25rem 1.5rem;
  margin-top: 1.25rem;
}

.talk h3 {
  margin: 0 0 0.2rem;
  font-size: 1.15rem;
}

.talk .meta {
  color: var(--muted);
  font-size: 0.9rem;
  margin-bottom: 0.75rem;
}

.talk .desc {
  margin-bottom: 1rem;
}

.viewer-frame {
  width: 100%;
  height: 70vh;
  min-height: 420px;
  border: 1px solid var(--border);
  border-radius: 8px;
}

.video-wrap {
  position: relative;
  width: 100%;
  padding-top: 56.25%;
  margin-top: 1rem;
  border-radius: 8px;
  overflow: hidden;
  border: 1px solid var(--border);
}

.video-wrap iframe {
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 100%;
  border: 0;
}

.placeholder {
  color: var(--muted);
  font-style: italic;
  font-size: 0.9rem;
  padding: 1.5rem;
  text-align: center;
  border: 1px dashed var(--border);
  border-radius: 8px;
}

.view-note {
  font-size: 0.78rem;
  color: var(--muted);
  margin-top: 0.5rem;
}

.external-link {
  display: inline-block;
  padding: 0.5rem 1rem;
  border: 1px solid var(--accent);
  border-radius: 6px;
  color: var(--accent);
  text-decoration: none;
  font-size: 0.9rem;
  font-weight: 600;
}

.external-link:hover {
  background: var(--accent);
  color: var(--bg);
}

footer {
  max-width: 860px;
  margin: 0 auto;
  padding: 1.5rem;
  color: var(--muted);
  font-size: 0.85rem;
  border-top: 1px solid var(--border);
}