/* ============================================================
   PostgreSQL İstanbul – Public Site CSS
   Design: Dark editorial, navy/electric-blue, Syne + Inter
   ============================================================ */

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

:root {
  --navy:       #0d1b2a;
  --navy-light: #162336;
  --navy-mid:   #1e3050;
  --blue:       #0072c3;
  --blue-bright:#1a8fff;
  --cyan:       #00c8d4;
  --white:      #f0f4f8;
  --grey:       #8fa3b8;
  --border:     rgba(255,255,255,.08);
  --radius:     6px;
  --transition: 200ms ease;
}

html { font-size: 16px; scroll-behavior: smooth; }
body {
  background: var(--navy);
  color: var(--white);
  font-family: 'Inter', sans-serif;
  font-weight: 400;
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* ---- Layout ---- */
.container { max-width: 1100px; margin: 0 auto; padding: 0 1.5rem; }

/* ---- Header ---- */
.site-header {
  border-bottom: 1px solid var(--border);
  position: sticky;
  top: 0;
  z-index: 100;
  background: rgba(13,27,42,.92);
  backdrop-filter: blur(12px);
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  height: 64px;
}

.logo {
  display: flex;
  align-items: center;
  gap: .6rem;
  text-decoration: none;
  color: var(--white);
}
.logo-elephant { font-size: 1.6rem; line-height: 1; }
.logo-text { font-family: 'Syne', sans-serif; font-size: .8rem; line-height: 1.25; }
.logo-text strong { display: block; font-size: 1rem; font-weight: 800; color: var(--cyan); }

.site-nav { display: flex; gap: 1.75rem; align-items: center; }
.nav-link {
  font-size: .85rem;
  font-weight: 500;
  color: var(--grey);
  text-decoration: none;
  letter-spacing: .03em;
  transition: color var(--transition);
}
.nav-link:hover, .nav-link.active { color: var(--white); }
.nav-link.lang-switch {
  border: 1px solid var(--border);
  padding: .25rem .7rem;
  border-radius: 99px;
  color: var(--grey);
}
.nav-link.lang-switch:hover { border-color: var(--cyan); color: var(--cyan); }

/* ---- Hero ---- */
.site-main { flex: 1; }

.hero {
  padding: 5rem 0 4rem;
  position: relative;
  overflow: hidden;
}
.hero::before {
  content: '';
  position: absolute;
  inset: 0;
  background:
    radial-gradient(ellipse 70% 60% at 20% 50%, rgba(0,114,195,.18) 0%, transparent 70%),
    radial-gradient(ellipse 50% 80% at 80% 20%, rgba(0,200,212,.08) 0%, transparent 60%);
  pointer-events: none;
}

.hero-label {
  font-family: 'Syne', sans-serif;
  font-size: .75rem;
  font-weight: 700;
  letter-spacing: .18em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: 1rem;
}

.hero-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(2.2rem, 5vw, 4rem);
  font-weight: 800;
  line-height: 1.1;
  color: var(--white);
  max-width: 800px;
  margin-bottom: 2rem;
}

.meta-row {
  display: flex;
  flex-direction: column;
  gap: .75rem;
  margin-bottom: 2.5rem;
}
.meta-item {
  display: flex;
  align-items: center;
  gap: .6rem;
  font-size: .95rem;
  color: var(--grey);
}
.meta-icon { font-size: 1rem; }
.map-link {
  color: var(--blue-bright);
  text-decoration: none;
  font-size: .8rem;
  margin-left: .25rem;
}
.map-link:hover { text-decoration: underline; }

.btn-register {
  display: inline-block;
  background: var(--blue);
  color: #fff;
  font-family: 'Syne', sans-serif;
  font-weight: 700;
  font-size: .9rem;
  letter-spacing: .04em;
  padding: .85rem 2.2rem;
  border-radius: var(--radius);
  text-decoration: none;
  transition: background var(--transition), transform var(--transition);
}
.btn-register:hover { background: var(--blue-bright); transform: translateY(-2px); }

/* ---- Talks ---- */
.talks-section {
  padding: 3rem 0 4rem;
  border-top: 1px solid var(--border);
}

.section-heading {
  font-family: 'Syne', sans-serif;
  font-size: 1.5rem;
  font-weight: 800;
  color: var(--white);
  margin-bottom: 2rem;
  display: flex;
  align-items: center;
  gap: .75rem;
}
.section-heading::after {
  content: '';
  flex: 1;
  height: 1px;
  background: var(--border);
}

.talks-grid {
  display: grid;
  gap: 1.5rem;
}

.talk-card {
  background: var(--navy-light);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 1.75rem;
  display: grid;
  grid-template-columns: 3rem 1fr;
  gap: 1.25rem;
  transition: border-color var(--transition);
}
.talk-card:hover { border-color: rgba(0,200,212,.3); }

.talk-number {
  font-family: 'Syne', sans-serif;
  font-size: 1.75rem;
  font-weight: 800;
  color: var(--navy-mid);
  line-height: 1;
  padding-top: .15rem;
}

.talk-title {
  font-family: 'Syne', sans-serif;
  font-size: 1.15rem;
  font-weight: 700;
  color: var(--white);
  margin-bottom: .5rem;
}
.talk-abstract {
  font-size: .9rem;
  color: var(--grey);
  margin-bottom: 1.25rem;
  line-height: 1.65;
}

.speaker-row {
  display: flex;
  align-items: flex-start;
  gap: .9rem;
}
.speaker-photo {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  object-fit: cover;
  border: 2px solid var(--navy-mid);
  flex-shrink: 0;
}
.speaker-name { font-size: .9rem; font-weight: 600; color: var(--white); display: block; }
.speaker-bio { font-size: .8rem; color: var(--grey); margin-top: .2rem; }

.talk-duration {
  font-size: .78rem;
  color: var(--grey);
  margin-top: .75rem;
  letter-spacing: .03em;
}

/* ---- Notes ---- */
.notes-section { padding: 0 0 4rem; }
.notes-box {
  background: var(--navy-light);
  border-left: 3px solid var(--cyan);
  border-radius: var(--radius);
  padding: 1.5rem;
  font-size: .9rem;
  color: var(--grey);
}
.notes-box h3 {
  font-family: 'Syne', sans-serif;
  font-size: .8rem;
  font-weight: 700;
  letter-spacing: .12em;
  text-transform: uppercase;
  color: var(--cyan);
  margin-bottom: .75rem;
}

/* ---- Empty hero ---- */
.hero--empty { text-align: center; padding: 7rem 0 6rem; }
.elephant-large { font-size: 5rem; margin-bottom: 1.5rem; }
.hero-empty-title {
  font-family: 'Syne', sans-serif;
  font-size: clamp(1.75rem, 4vw, 3rem);
  font-weight: 800;
  margin-bottom: 1rem;
  color: var(--white);
}
.hero-empty-sub {
  font-size: 1rem;
  color: var(--grey);
  max-width: 520px;
  margin: 0 auto 2.5rem;
  line-height: 1.7;
}
.social-links { display: flex; gap: 1rem; justify-content: center; flex-wrap: wrap; }
.social-btn {
  display: inline-block;
  border: 1px solid var(--border);
  color: var(--grey);
  padding: .55rem 1.25rem;
  border-radius: 99px;
  font-size: .85rem;
  font-weight: 500;
  text-decoration: none;
  transition: border-color var(--transition), color var(--transition);
}
.social-btn:hover { border-color: var(--cyan); color: var(--cyan); }

/* ---- Previous page ---- */
.page-hero {
  padding: 3.5rem 0 2rem;
  border-bottom: 1px solid var(--border);
}
.page-hero h1 {
  font-family: 'Syne', sans-serif;
  font-size: clamp(1.8rem, 4vw, 3rem);
  font-weight: 800;
  margin-bottom: .5rem;
}
.page-hero p { color: var(--grey); }

.past-section { padding: 3rem 0 5rem; }

.past-list { display: grid; gap: 2rem; }
.past-card {
  background: var(--navy-light);
  border: 1px solid var(--border);
  border-radius: 10px;
  padding: 2rem;
}
.past-card-header { margin-bottom: 1.5rem; }
.past-date { font-size: .8rem; color: var(--cyan); font-weight: 600; letter-spacing: .05em; margin-bottom: .4rem; }
.past-venue {
  font-family: 'Syne', sans-serif;
  font-size: 1.3rem;
  font-weight: 800;
  color: var(--white);
  margin-bottom: .4rem;
}
.past-address { font-size: .85rem; color: var(--grey); }

.past-talks { display: grid; gap: .75rem; }
.past-talk {
  display: flex;
  gap: 1rem;
  padding: .75rem 1rem;
  background: var(--navy);
  border-radius: var(--radius);
  border: 1px solid var(--border);
}
.past-talk-title { font-size: .9rem; font-weight: 600; color: var(--white); flex: 1; }
.past-talk-speaker { font-size: .8rem; color: var(--grey); flex-shrink: 0; align-self: center; }
.past-notes { font-size: .85rem; color: var(--grey); margin-top: 1rem; }

.empty-state { text-align: center; padding: 4rem; color: var(--grey); }

/* ---- Footer ---- */
.site-footer {
  border-top: 1px solid var(--border);
  padding: 1.5rem 0;
  font-size: .8rem;
  color: var(--grey);
}
.footer-inner {
  display: flex;
  gap: .75rem;
  align-items: center;
  flex-wrap: wrap;
}
.footer-sep { color: var(--border); }
.site-footer a { color: var(--grey); text-decoration: none; }
.site-footer a:hover { color: var(--white); }

@media (max-width: 640px) {
  .site-nav { gap: 1rem; }
  .talk-card { grid-template-columns: 1fr; }
  .talk-number { font-size: 1rem; }
  .past-talk { flex-direction: column; gap: .25rem; }
}