:root {
  --black: #0a0a0a;
  --ink: #141414;
  --white: #ffffff;
  --yellow: #ffd60a;
  --muted: #c8c8c8;
  --error: #ff5c5c;
}

* { box-sizing: border-box; margin: 0; padding: 0; }

html { scroll-behavior: smooth; }
[hidden] { display: none !important; }

body {
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  background: var(--white);
  color: var(--black);
  line-height: 1.5;
  -webkit-font-smoothing: antialiased;
}

a:focus-visible, button:focus-visible, input:focus-visible {
  outline: 3px solid var(--yellow);
  outline-offset: 3px;
}

/* Hero */
.hero { background: var(--black); color: var(--white); padding: 0 20px 56px; }
.navbar {
  display: flex; justify-content: space-between; align-items: center;
  padding: 18px 0; max-width: 960px; margin: 0 auto;
}
.logo { font-weight: 900; font-size: 1.1rem; letter-spacing: 0.04em; }
.accent { color: var(--yellow); }
.nav-cta {
  color: var(--black); background: var(--yellow); font-weight: 800;
  padding: 10px 16px; text-decoration: none; text-transform: uppercase; font-size: 0.85rem;
}
.hero-content { max-width: 960px; margin: 0 auto; padding-top: 40px; }
.eyebrow { color: var(--yellow); font-weight: 800; letter-spacing: 0.12em; font-size: 0.8rem; }
.hero h1 {
  font-size: clamp(3rem, 15vw, 7.5rem); font-weight: 900; line-height: 0.92;
  letter-spacing: -0.03em; margin: 14px 0 18px;
}
.hero-sub { font-size: 1.15rem; color: var(--muted); max-width: 34ch; }
.hero-meta {
  display: grid; grid-template-columns: repeat(3, 1fr); gap: 12px;
  margin: 32px 0; border-top: 2px solid var(--white); padding-top: 18px;
}
.meta-label { display: block; font-size: 0.7rem; font-weight: 800; color: var(--yellow); letter-spacing: 0.1em; }
.meta-value { font-weight: 700; font-size: 0.95rem; }

/* Buttons */
.btn-primary, .btn-secondary {
  display: inline-block; font-weight: 900; text-transform: uppercase; text-decoration: none;
  padding: 16px 24px; font-size: 1rem; border: 3px solid var(--yellow); cursor: pointer;
  font-family: inherit; min-height: 48px;
}
.btn-primary { background: var(--yellow); color: var(--black); }
.btn-primary:hover { background: var(--white); border-color: var(--white); }
.btn-primary:disabled { opacity: 0.6; cursor: wait; }
.btn-secondary { background: var(--black); color: var(--yellow); }
.btn-secondary:hover { background: var(--yellow); color: var(--black); }
.btn-full { width: 100%; margin-top: 8px; }

/* Sections */
.section { padding: 64px 20px; }
.section > * { max-width: 960px; margin-left: auto; margin-right: auto; }
.section-dark { background: var(--black); color: var(--white); }
.section-title {
  font-size: clamp(2.4rem, 11vw, 4.5rem); font-weight: 900; line-height: 1;
  letter-spacing: -0.02em;
}
.section-sub { font-size: 1.05rem; margin: 10px auto 32px; font-weight: 600; }
.section-dark .section-sub { color: var(--muted); }

/* Schedule */
.schedule-list { list-style: none; border-top: 4px solid var(--black); }
.schedule-item {
  display: grid; grid-template-columns: 76px 1fr; gap: 14px;
  padding: 20px 0; border-bottom: 2px solid var(--black);
}
.time {
  font-weight: 900; font-size: 1.1rem; background: var(--black); color: var(--yellow);
  align-self: start; text-align: center; padding: 6px 0;
}
.talk-info h3 { font-size: 1.2rem; font-weight: 900; line-height: 1.2; }
.talk-info p { margin-top: 6px; }
.talk-speaker { font-weight: 800; text-transform: uppercase; font-size: 0.8rem; letter-spacing: 0.06em; }

/* Speakers */
.speaker-grid { display: grid; grid-template-columns: 1fr; gap: 14px; }
.speaker-card {
  display: grid; grid-template-columns: 64px 1fr; column-gap: 16px; align-items: center;
  border: 2px solid var(--white); padding: 16px;
}
.speaker-avatar {
  grid-row: span 2; width: 64px; height: 64px; background: var(--yellow); color: var(--black);
  display: flex; align-items: center; justify-content: center; font-weight: 900; font-size: 1.3rem;
}
.speaker-card h3 { font-size: 1.1rem; font-weight: 900; }
.speaker-role { color: var(--yellow); font-weight: 600; font-size: 0.9rem; }

/* Venue */
.venue-box { border: 4px solid var(--black); padding: 24px; margin-top: 24px; box-shadow: 8px 8px 0 var(--yellow); }
.venue-details h3 { font-size: 1.5rem; font-weight: 900; }
.venue-details p { margin: 8px 0; font-weight: 600; }
.venue-note { color: #333; }
.venue-details .btn-secondary { margin-top: 12px; }

/* Form */
.register-form { display: flex; flex-direction: column; max-width: 520px; }
.register-form label { font-weight: 800; text-transform: uppercase; font-size: 0.8rem; letter-spacing: 0.08em; margin: 14px 0 6px; }
.register-form input {
  font: inherit; font-size: 1.05rem; padding: 14px; background: var(--white); color: var(--black);
  border: 3px solid var(--white); min-height: 52px;
}
.register-form input[aria-invalid="true"] { border-color: var(--error); }
.form-msg { min-height: 1.5em; margin-top: 12px; font-weight: 700; }
.form-msg.error { color: var(--error); }
.registered-list { max-width: 520px; border: 3px solid var(--yellow); padding: 20px; }
.registered-list h3 { color: var(--yellow); font-weight: 900; font-size: 1.3rem; }
.registered-list p { margin-top: 8px; }

.footer { background: var(--yellow); color: var(--black); text-align: center; padding: 24px 20px; font-weight: 800; }

@media (min-width: 700px) {
  .speaker-grid { grid-template-columns: repeat(2, 1fr); }
  .schedule-item { grid-template-columns: 110px 1fr; gap: 24px; }
}
@media (min-width: 960px) {
  .speaker-grid { grid-template-columns: repeat(3, 1fr); }
}

/* Keep narrow form/confirmation left-aligned with section headings */
.section > .register-form, .section > .registered-list {
  margin-left: max(0px, calc((100% - 960px) / 2));
  margin-right: auto;
}