/* === Custom Properties === */
:root {
  --stanford-red: #8C1515;
  --dark-red: #5E0F0F;
  --accent-red: #B83A4B;
  --warm-bg: #F3EFEC;
  --warm-dark: #F0E7DE;
  --dark-text: #2e2d29;
  --muted-text: #585754;
  --white: #FFFFFF;
  --shadow: 0 2px 8px rgba(0, 0, 0, 0.08);
  --shadow-hover: 0 4px 16px rgba(0, 0, 0, 0.12);
  --max-width: 920px;
  --nav-height: 56px;
  --font-stack: "Source Sans Pro", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* === Reset & Base === */
*, *::before, *::after {
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
  scroll-padding-top: var(--nav-height);
}

body {
  margin: 0;
  font-family: var(--font-stack);
  font-size: 16px;
  line-height: 1.65;
  color: var(--dark-text);
  background: var(--warm-bg);
}

img {
  max-width: 100%;
  height: auto;
}

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

a:hover {
  text-decoration: underline;
}

/* === Layout === */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

.content-layer {
  position: relative;
  z-index: 1;
}

/* === Navigation === */
.navbar {
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  height: var(--nav-height);
  background: var(--stanford-red);
  z-index: 100;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.15);
}

.nav-container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
  display: flex;
  align-items: center;
  height: 100%;
}

.nav-brand {
  color: var(--white);
  font-weight: 600;
  font-size: 1.05rem;
  letter-spacing: 0.01em;
  margin-right: auto;
}

.nav-brand:hover {
  text-decoration: none;
  opacity: 0.9;
}

.nav-links {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 1.5rem;
}

.nav-links a {
  color: rgba(255, 255, 255, 0.9);
  font-size: 0.88rem;
  font-weight: 500;
  letter-spacing: 0.01em;
}

.nav-links a:hover {
  color: var(--white);
  text-decoration: none;
}

.nav-toggle {
  display: none;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.nav-toggle span {
  display: block;
  width: 22px;
  height: 2px;
  background: var(--white);
  margin: 5px 0;
  transition: 0.3s;
}

/* === Hero === */
.hero {
  padding: 8rem 0 4rem;
  background: linear-gradient(135deg, rgba(243, 239, 236, 0.85) 0%, rgba(240, 231, 222, 0.85) 100%);
  text-align: center;
  border-bottom: 4px solid var(--stanford-red);
}

.hero h1 {
  font-size: 2.4rem;
  font-weight: 700;
  color: var(--stanford-red);
  line-height: 1.2;
  margin: 0 0 0.75rem;
  max-width: 750px;
  margin-left: auto;
  margin-right: auto;
}

.hero-subtitle {
  font-size: 1.25rem;
  color: var(--dark-text);
  font-weight: 500;
  margin: 0 0 0.25rem;
}

.hero-meta {
  font-size: 1rem;
  color: var(--muted-text);
  margin: 0;
}

/* === Sections === */
.section {
  padding: 4rem 0;
  background: rgba(255, 255, 255, 0.82);
}

.section-warm {
  background: rgba(243, 239, 236, 0.82);
}

.section h2 {
  font-size: 1.75rem;
  font-weight: 700;
  color: var(--stanford-red);
  margin: 0 0 1.5rem;
  padding-left: 0.75rem;
  border-left: 4px solid var(--stanford-red);
}

.section h3 {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--dark-text);
  margin: 2rem 0 0.75rem;
}

.section-note {
  font-style: italic;
  color: var(--muted-text);
  margin-bottom: 1.5rem;
}

/* === Cards === */
.card-grid {
  display: grid;
  gap: 1.5rem;
}

.card-grid-3 {
  grid-template-columns: repeat(3, 1fr);
}

.card {
  background: rgba(255, 255, 255, 0.88);
  border-radius: 8px;
  padding: 1.75rem 1.5rem;
  box-shadow: var(--shadow);
  transition: box-shadow 0.2s ease;
  backdrop-filter: blur(4px);
}

.section-warm .card {
  background: rgba(255, 255, 255, 0.88);
}

.card:hover {
  box-shadow: var(--shadow-hover);
}

/* === Avatar / Initials === */
.avatar {
  width: 72px;
  height: 72px;
  border-radius: 50%;
  background: var(--stanford-red);
  color: var(--white);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.4rem;
  font-weight: 700;
  margin: 0 auto 1rem;
  letter-spacing: 0.05em;
}

/* === Speaker / Organizer Cards === */
.speaker-card,
.organizer-card {
  text-align: center;
}

.speaker-card h3,
.organizer-card h3 {
  font-size: 1.05rem;
  margin: 0 0 0.25rem;
  color: var(--dark-text);
}

.affiliation {
  font-size: 0.88rem;
  color: var(--muted-text);
  margin: 0 0 0.75rem;
}

.bio {
  font-size: 0.88rem;
  color: var(--dark-text);
  line-height: 1.55;
  margin: 0;
}

/* === Topic Cards === */
.topic-card {
  background: rgba(255, 255, 255, 0.85);
  border-radius: 8px;
  padding: 1.25rem 1.5rem;
  margin-bottom: 1rem;
  box-shadow: var(--shadow);
  border-left: 3px solid var(--stanford-red);
  backdrop-filter: blur(4px);
}

.topic-card h4 {
  font-size: 1rem;
  font-weight: 600;
  color: var(--stanford-red);
  margin: 0 0 0.5rem;
}

.topic-card p {
  margin: 0;
  font-size: 0.92rem;
  line-height: 1.6;
}

.topic-list {
  margin-top: 1.5rem;
}

.topic-list h4 {
  font-size: 1rem;
  font-weight: 600;
  margin: 0 0 0.5rem;
}

.topic-list ul {
  margin: 0;
  padding-left: 1.25rem;
}

.topic-list li {
  font-size: 0.92rem;
  margin-bottom: 0.35rem;
}

/* === Schedule Table === */
.schedule-table-wrap {
  overflow-x: auto;
}

.schedule-table {
  width: 100%;
  border-collapse: collapse;
  font-size: 0.92rem;
  background: rgba(255, 255, 255, 0.85);
  border-radius: 8px;
  overflow: hidden;
  box-shadow: var(--shadow);
  backdrop-filter: blur(4px);
}

.schedule-table tr {
  border-bottom: 1px solid #eae6e1;
}

.schedule-table tr:last-child {
  border-bottom: none;
}

.schedule-time {
  padding: 0.85rem 1rem;
  white-space: nowrap;
  font-weight: 600;
  color: var(--muted-text);
  width: 140px;
  vertical-align: top;
}

.schedule-event {
  padding: 0.85rem 1rem;
}

.schedule-event strong {
  color: var(--dark-text);
}

.schedule-speaker {
  color: var(--stanford-red);
  font-weight: 500;
}

.schedule-detail {
  display: block;
  font-size: 0.82rem;
  color: var(--muted-text);
  margin-top: 0.15rem;
}

.schedule-break {
  background: rgba(249, 247, 245, 0.8);
}

.schedule-break .schedule-event strong {
  color: var(--muted-text);
  font-weight: 500;
}

.schedule-invited .schedule-event strong {
  color: var(--stanford-red);
}

.contributed-note {
  margin-top: 2rem;
  padding: 1.25rem 1.5rem;
  background: rgba(255, 255, 255, 0.85);
  border-radius: 8px;
  box-shadow: var(--shadow);
  backdrop-filter: blur(4px);
}

.contributed-note h3 {
  margin-top: 0;
}

.contributed-note p {
  margin-bottom: 0;
  font-size: 0.92rem;
}

/* === Call for Papers === */
#cfp ul {
  padding-left: 1.25rem;
  margin: 1rem 0 1.5rem;
}

#cfp li {
  margin-bottom: 0.4rem;
  font-size: 0.95rem;
}

.deadline-box {
  background: rgba(140, 21, 21, 0.08);
  border-left: 4px solid var(--stanford-red);
  padding: 0.85rem 1.25rem;
  border-radius: 0 6px 6px 0;
  margin: 1.25rem 0;
  font-size: 1.05rem;
}

.cta-wrap {
  text-align: center;
  margin: 2rem 0 0.5rem;
}

.btn {
  display: inline-block;
  padding: 0.8rem 2rem;
  border-radius: 6px;
  font-size: 1rem;
  font-weight: 600;
  text-decoration: none;
  transition: background 0.2s, box-shadow 0.2s;
}

.btn-primary {
  background: var(--stanford-red);
  color: var(--white);
  box-shadow: 0 2px 8px rgba(140, 21, 21, 0.3);
}

.btn-primary:hover {
  background: var(--dark-red);
  text-decoration: none;
  box-shadow: 0 4px 12px rgba(140, 21, 21, 0.4);
}

/* === Contact === */
.contact-email {
  font-size: 1.15rem;
  font-weight: 500;
}

.contact-email a {
  color: var(--stanford-red);
}

/* === Footer === */
.footer {
  background: var(--stanford-red);
  color: rgba(255, 255, 255, 0.8);
  padding: 1.5rem 0;
  text-align: center;
  font-size: 0.85rem;
}

.footer p {
  margin: 0;
}

/* === Background Conversation === */
.pd-conversation {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  z-index: 0;
  pointer-events: none;
  opacity: 0.4;
  padding: 5rem 2rem 2rem;
  overflow: hidden;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.pd-bubble {
  max-width: 520px;
  padding: 0.85rem 1.1rem;
  border-radius: 12px;
  font-size: 13px;
  line-height: 1.5;
}

.pd-bubble p {
  margin: 0;
}

.pd-label {
  display: block;
  font-weight: 700;
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: 0.3rem;
}

.pd-left {
  align-self: flex-start;
  background: rgba(140, 21, 21, 0.12);
  color: var(--dark-text);
  border-bottom-left-radius: 4px;
}

.pd-right {
  align-self: flex-end;
  background: rgba(58, 58, 58, 0.1);
  color: var(--dark-text);
  border-bottom-right-radius: 4px;
}

/* === Responsive === */
@media (max-width: 768px) {
  .card-grid-3 {
    grid-template-columns: repeat(2, 1fr);
  }

  .hero h1 {
    font-size: 1.75rem;
  }

  .section {
    padding: 3rem 0;
  }

  .nav-toggle {
    display: block;
  }

  .nav-links {
    display: none;
    position: absolute;
    top: var(--nav-height);
    left: 0;
    right: 0;
    background: var(--stanford-red);
    flex-direction: column;
    padding: 1rem 1.5rem;
    gap: 0.75rem;
    box-shadow: 0 4px 8px rgba(0, 0, 0, 0.15);
  }

  .nav-links.active {
    display: flex;
  }

  .pd-conversation {
    display: none;
  }
}

@media (max-width: 480px) {
  .card-grid-3 {
    grid-template-columns: 1fr;
  }

  .hero {
    padding: 6rem 0 2.5rem;
  }

  .hero h1 {
    font-size: 1.5rem;
  }

  .section h2 {
    font-size: 1.4rem;
  }
}