body {
  font-family: 'Segoe UI', 'Hiragino Sans', 'Meiryo', sans-serif;
  background: #0a1a2f;
  color: #e5e7eb;
  margin: 0;
  padding: 0;
}

header {
  background: linear-gradient(90deg, #22304a 0%, #1e293b 100%);
  padding: 1.5rem 0.5rem;
  text-align: center;
  box-shadow: 0 2px 8px rgba(0,0,0,0.18);
}

header h1 {
  margin: 0 0 0.5rem 0;
  font-size: 2rem;
  letter-spacing: 1px;
  color: #e5e7eb;
}

header a {
  color: #60a5fa;
  text-decoration: none;
  font-weight: bold;
  border-bottom: 2px solid #60a5fa;
  padding-bottom: 2px;
  transition: color 0.2s;
}
header a:hover {
  color: #fff;
  border-bottom: 2px solid #fff;
}

main {
  max-width: 900px;
  margin: 2rem auto;
  padding: 0 1rem;
}

section {
  margin-bottom: 2.5rem;
  background: #16213a;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(30,58,138,0.18);
  padding: 2rem 1.5rem;
}

h2 {
  margin-top: 0;
  color: #60a5fa;
  font-size: 1.5rem;
  letter-spacing: 1px;
}

table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  margin-top: 1rem;
  background: #16213a;
  border-radius: 12px;
  box-shadow: 0 2px 12px rgba(30,58,138,0.18);
  overflow: hidden;
}
thead th {
  background: #22304a;
  color: #60a5fa;
  font-weight: bold;
  padding: 1rem 0.7rem;
  border-radius: 0;
  font-size: 1.05rem;
  letter-spacing: 1px;
}
tbody td {
  padding: 1rem 0.7rem;
  border-bottom: 1px solid #22304a;
  text-align: center;
  font-size: 1rem;
  color: #e5e7eb;
}
tbody tr:last-child td {
  border-bottom: none;
}
tbody tr {
  transition: background 0.2s;
}
tbody tr:hover {
  background: #22304a;
}

.list-container {
  display: flex;
  flex-wrap: wrap;
  gap: 1.5rem;
  margin-top: 1rem;
  width: 100%;
  box-sizing: border-box;
}
.talks-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
  width: 100%;
}
.talk-card {
  background: #22304a;
  border-radius: 10px;
  box-shadow: 0 2px 8px rgba(30,58,138,0.18);
  padding: 10px;
  width: 95%;
  flex: 1 1 100%;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}
.talk-info h3 {
  margin: 0 0 0.3rem 0;
  font-size: 1.1rem;
  color: #60a5fa;
}
.talk-info span {
  font-size: 0.95rem;
  color: #e5e7eb;
}
.talk-export {
  margin-top: 1rem;
  display: flex;
  gap: 0.7rem;
}
.talk-export a {
  background: #1e293b;
  color: #60a5fa;
  text-decoration: none;
  padding: 0.4rem 0.9rem;
  border-radius: 6px;
  font-size: 0.95rem;
  font-weight: bold;
  transition: background 0.2s, color 0.2s;
}
.talk-export a:hover {
  background: #60a5fa;
  color: #1e293b;
}

@media (max-width: 600px) {
  main {
    padding: 0 0.3rem;
  }
  section {
    padding: 1.2rem 0.5rem;
  }
  .list-container {
    flex-direction: column;
    gap: 1rem;
  }
  .talk-card {
    min-width: 0;
    max-width: 100%;
  }
}