/* リセットとベーススタイル */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: 'ヒラギノ角ゴ Pro W3', 'Hiragino Kaku Gothic Pro', 'メイリオ', 'Meiryo', 'ＭＳ Ｐゴシック', 'MS PGothic', sans-serif;
  line-height: 1.6;
  color: #483423;
  background-color: #603813;
}

a {
  color: #0000FF;
  text-decoration: underline;
}

a:hover {
  color: #0000FF;
}

a:active {
  color: #D4145A;
}

/* コンテナとレイアウト */
.container {
  width: 850px;
  margin: 0 auto;
  background-color: #FFFF99;
  padding-bottom: 49px;
  min-height: 1500px;
}

/* ヘッダー */
header {
  position: relative;
}

.header-color-bar {
  height: 180px;
  background-color: #8F320A;
  width: 100%;
}

.seminar-title {
  background-color: #483423;
  padding: 20px 0;
  margin-bottom: 10px;
}

h1 {
  font-size: 45px;
  color: #FFFFFF;
  font-weight: bold;
  text-align: center;
}

/* 共通セクションスタイル */
section {
  margin: 20px 0;
  padding: 0 20px;
}

h2 {
  font-size: 20px;
  color: #483423;
  font-weight: bold;
  margin-bottom: 10px;
  text-decoration: underline;
}

/* 次回のセミナー */
.next-seminar {
  margin: 20px auto;
  width: 90%;
}

.section-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 10px;
}

.section-header h2 {
  background-color: #483423;
  color: #FFFFFF;
  padding: 10px;
  font-size: 22px;
  margin-bottom: 0;
  width: 65%;
  text-decoration: none;
}

.update-info {
  font-size: 16px;
  text-align: right;
  width: 35%;
}

.seminar-content {
  border: 4px solid #483423;
  padding: 20px;
  font-size: 18px;
  line-height: 32px;
}

.presentation {
  margin-bottom: 20px;
}

.presentation p {
  margin-bottom: 8px;
}

/* セミナー情報 */
.seminar-info {
  background-color: #483423;
  color: #FFFFFF;
  padding: 20px;
  width: 90%;
  margin: 20px auto;
}

.seminar-info h2 {
  color: #FFFFFF;
  text-decoration: none;
  font-size: 24px;
  margin-bottom: 15px;
}

.info-details {
  font-size: 16px;
  line-height: 28px;
}

/* 発表要旨 */
.abstracts {
  background-color: #B5FFFF;
  padding: 15px;
  text-align: center;
  width: 65%;
  margin: 20px auto;
}

.abstracts a {
  font-size: 17px;
  font-weight: bold;
}

/* リンク集 */
.links-section {
  width: 90%;
  margin: 30px auto;
}

.links-container {
  border: 4px solid #483423;
  padding: 20px;
  display: flex;
  justify-content: space-between;
}

.links-left {
  width: 65%;
}

.links-right {
  width: 30%;
  text-align: right;
}

.links-section p, .archives-section p {
  font-size: 17px;
  line-height: 26px;
  margin-bottom: 10px;
}

/* アーカイブ */
.archives-section {
  width: 90%;
  margin: 30px auto;
}

.archives-list {
  border: 4px solid #483423;
  padding: 20px;
}

.archives-old {
  display: flex;
  justify-content: space-between;
  margin-top: 15px;
}

/* スタッフ */
.staff-section {
  width: 90%;
  margin: 30px auto;
}

.staff-list {
  border: 4px solid #483423;
  padding: 20px;
}

.staff-section p {
  font-size: 16px;
  line-height: 28px;
  margin-bottom: 10px;
}

/* レスポンシブデザイン */
@media (max-width: 900px) {
  .container {
    width: 95%;
  }
  
  .section-header {
    flex-direction: column;
  }
  
  .section-header h2, .update-info {
    width: 100%;
    text-align: left;
  }
  
  .update-info {
    margin-top: 10px;
  }
  
  .links-container {
    flex-direction: column;
  }
  
  .links-left, .links-right {
    width: 100%;
  }
  
  .links-right {
    text-align: left;
    margin-top: 20px;
  }
  
  .archives-old {
    flex-direction: column;
  }
  
  .abstracts {
    width: 90%;
  }
}