/* グレー基調（メインカラーなし・ニュートラルアクセント） */
:root {
  --accent: #c4c4cc;
  --accent-hover: #e0e0e8;
  --accent-bg: rgba(255, 255, 255, 0.08);
  /* グレー基調 */
  --bg-base: #2d2d32;
  --bg-section: #38383e;
  --bg-card: #42424a;
  --bg-card-hover: #4a4a54;
  --text: #e8e8ec;
  --text-muted: #b0b0b8;
  --white: #fff;
  --border: rgba(255, 255, 255, 0.12);
  --border-strong: rgba(255, 255, 255, 0.2);
  --shadow: 0 8px 32px rgba(0, 0, 0, 0.35);
  --radius: 8px;
  --font: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, sans-serif;
}

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

html {
  font-size: 75%;  /* 16px → 12px：rem ベースを約25%縮小 */
  scroll-behavior: smooth;
}

body {
  margin: 0;
  font-family: var(--font);
  font-size: 19.5px;  /* 26px の約25%縮小 */
  line-height: 1.75;
  color: var(--text);
  background: var(--bg-base);
}

.container {
  max-width: min(1920px, 90%);
  margin: 0 auto;
  padding: 0 2.5rem;
}

/* ========== Hero ========== */
.hero {
  position: relative;
  background: linear-gradient(135deg, rgba(0, 0, 0, 0.65) 0%, rgba(0, 0, 0, 0.5) 100%),
    url('../img/bg_mtg_room.jpg') center / cover no-repeat;
  background-color: var(--bg-base);
  color: var(--text);
  padding: 6rem 2.5rem 8rem;
  text-align: center;
  min-height: 50vh;
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Hero下部の境目ぼかし（次のセクションへの滑らかな繋がり） */
.hero::after {
  content: "";
  position: absolute;
  left: 0;
  right: 0;
  bottom: 0;
  height: 120px;
  background: linear-gradient(to bottom, transparent, rgba(0, 0, 0, 0.7));
  pointer-events: none;
}

.hero-inner {
  margin: 0 auto;
  position: relative;
  z-index: 1;
}

.hero-logo {
  position: absolute;
  right: -10rem;
  top: -8rem;
  transform: translateY(10%);
  width: min(570px, 57vw);
  height: auto;
  object-fit: contain;
  opacity: 0.5;
  z-index: -1;
}

.hero-event-name {
  margin: 0 0 2rem 0;
  font-size: clamp(3.9rem, 9vw, 6.5rem);
  font-weight: 700;
  line-height: 1.25;
  letter-spacing: 0.02em;
}

.hero-message-line1 {
  margin: 0 0 0.5rem 0;
  font-size: clamp(2.15rem, 4.6vw, 2.9rem);
  font-weight: 600;
}

/* スマホ以外では <br> を非表示（1行表示） */
.hero-message-line1 br {
  display: none;
}

.hero-organizer {
  margin: 2rem auto 0;
  display: inline-flex;
  flex-direction: column;
  align-items: flex-start;
  padding: 1.4rem 2.2rem;
  border-radius: 4px;
  background: rgba(0, 0, 0, 0.55);
  backdrop-filter: blur(3px);
  text-align: left;
  gap: 0.15rem;
}

.hero-organizer span {
  display: block;
}

.hero-organizer__venue {
  font-size: clamp(2.1rem, 4.6vw, 3rem);
  font-weight: 700;
  letter-spacing: 0.12em;
}

.hero-organizer__date {
  margin-top: 0.3rem;
  font-size: clamp(2.6rem, 5.4vw, 3.6rem);
  font-weight: 700;
  letter-spacing: 0.12em;
}

.hero-organizer__day {
  font-size: 0.7em;
  margin-left: 0.4rem;
}

.hero-organizer__time {
  margin-top: 0.4rem;
  font-size: clamp(1.2rem, 2.4vw, 1.6rem);
  font-weight: 500;
  opacity: 0.9;
}

.hero-organizer__open {
  font-size: 0.9em;
}

.hero-organizer__host {
  margin-top: 0.4rem;
  font-size: clamp(1.1rem, 2.2vw, 1.4rem);
  font-weight: 500;
  opacity: 0.85;
}

.hero-overview {
  margin: 5rem auto 0;
  max-width: 72ch;
  font-size: clamp(1.4rem, 2.5vw, 1.6rem);
  line-height: 1.85;
  text-align: center;
  opacity: 0.95;
}

/* ========== Section common ========== */
.section {
  position: relative;
  padding: 5.5rem 0;
}

/* セクション境目の継ぎ接ぎ感を和らげる（黒基調のぼかし） */
.section::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to bottom, rgba(0, 0, 0, 0.55) 0%, transparent 18%),
    linear-gradient(to top, rgba(0, 0, 0, 0.55) 0%, transparent 18%);
  background-size: 100% 100%, 100% 100%;
  background-position: top, bottom;
  background-repeat: no-repeat;
  z-index: 1;
}

.section .container {
  position: relative;
  z-index: 2;
}

.section:nth-of-type(even) {
  background: var(--bg-section);
}

.section-heading {
  position: relative;
  margin: 0 0 2rem 0;
  font-size: clamp(2.9rem, 6.5vw, 4.25rem);
  font-weight: 700;
  color: var(--text);
  text-align: center;
  letter-spacing: 0.05em;
}

/* 背景の英語テキスト（ウォーターマーク風） */
.section-heading__en {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  font-size: clamp(4rem, 12vw, 8rem);
  font-weight: 800;
  color: var(--text);
  opacity: 0.06;
  letter-spacing: 0.08em;
  white-space: nowrap;
  pointer-events: none;
  z-index: 0;
}

/* 前面の日本語テキスト */
.section-heading__main {
  position: relative;
  z-index: 1;
}

.section-lead {
  margin: 0 0 2.5rem 0;
  text-align: center;
  color: var(--text-muted);
  font-size: 1.7rem;
  line-height: 1.75;
}

/* ========== TIME TABLE（時間・会場はマトリクス外、セッションのみマトリクス） ========== */
/* .section:nth-of-type(even) より詳細度を上げて背景画像を表示（オーバーレイのalphaで視認性を調整） */
.section.section-timetable {
  position: relative;
  background: linear-gradient(135deg, rgba(0, 0, 0, 0.65) 0%, rgba(0, 0, 0, 0.5) 100%),
    var(--bg-section) url("../img/bg_timetable_sec.jpg") center center / cover no-repeat;
}

.section-timetable .container {
  max-width: min(1920px, 90%);
}

/* TIME TABLE の視認性向上（背景画像上で見やすく） */
.section-timetable .section-heading__en {
  opacity: 0.15;
  color: rgba(255, 255, 255, 0.9);
}

/* 日時・会場（タイトル直下） */
.timetable-info {
  margin: 2rem 0 10rem 0;
  font-size: clamp(1.2rem, 2.2vw, 1.6rem);
  color: var(--text);
  line-height: 1.6;
  text-align: center;
}

.timetable-info__item {
  display: block;
}

.timetable-info__item + .timetable-info__item {
  margin-top: 0.35rem;
}

/* 横スクロール：テーブルがはみ出す場合は横スクロール、スクロールバー非表示 */
.timetable-scroll-outer {
  position: relative;
  margin: 0 -2.5rem;  /* containerのpaddingを打ち消して端まで広げる */
  padding: 0 2.5rem;
}

.timetable-scroll-wrapper {
  overflow-x: auto;
  overflow-y: visible;
  scrollbar-width: none;  /* Firefox */
  -ms-overflow-style: none;  /* IE/Edge */
}

.timetable-scroll-wrapper::-webkit-scrollbar {
  display: none;  /* Chrome/Safari */
}

.timetable-layout {
  display: grid;
  grid-template-columns: 12rem minmax(220px, 1fr) minmax(220px, 1fr) minmax(220px, 1fr) minmax(220px, 1fr);
  /* 各セッション列の最小幅220px、合計最小: 12rem + 880px */
  min-width: calc(12rem + 880px + 2.25rem);  /* 時間列 + 4列×220px + カラム間ギャップ */
  /* 4行×8.6rem + 3×行間0.5rem = 35.9rem（時間とセッションの縦中央を揃える） */
  grid-template-rows: auto 35.9rem;
  gap: 0;
  font-size: clamp(1rem, 1.8vw, 1.25rem);
  align-items: stretch;
}

/* 会場ラベル（マトリクス上・外） */
.timetable-venues {
  grid-column: 2 / -1;
  grid-row: 1;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding-bottom: 1.5rem;
}

.timetable-venue {
  text-align: center;
  font-weight: 600;
  color: var(--text);
  font-size: 0.9em;
  word-break: keep-all;
}

/* 時間ラベル（マトリクス左・外） */
.timetable-times {
  grid-column: 1;
  grid-row: 2 / -1;
  display: grid;
  grid-template-rows: repeat(4, 8.6rem);
  row-gap: 0.5rem;
  padding-right: 1rem;
}

.timetable-time {
  font-weight: 700;
  color: var(--accent);
  display: flex;
  align-items: center;
}

/* セッション領域（4×4、それぞれ独立ボタン風） */
.timetable-matrix {
  grid-column: 2 / -1;
  grid-row: 2 / -1;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  grid-template-rows: repeat(4, 8.6rem);
  row-gap: 0.5rem;
  column-gap: 0.75rem;
}

/* 各セル＝独立ボタン風 */
.timetable-cell {
  padding: 1rem 0.5rem;
  border-radius: var(--radius);
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  background: rgba(0, 0, 0, 0.1);
  min-height: 8.6rem;
  box-sizing: border-box;
}

/* セッションタイトル（基調講演・個別セッション・懇親会）は親の90% */
.timetable-cell--has-session {
  font-size: clamp(0.9rem, 1.62vw, 1.125rem);
}

.timetable-cell--has-session[data-session-ids] {
  font-size: clamp(0.9rem, 1.26vw, 1.08rem);
  line-height: 1.4;
  overflow-wrap: break-word;
  white-space: pre-line;  /* \n で改行可能 */
}

.timetable-cell--has-session[role="button"] {
  background: rgba(70, 72, 78, 0.92);
  color: var(--text);
  font-weight: 500;
  border: 1px solid var(--border-strong);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: box-shadow 0.2s, border-color 0.2s, background 0.2s;
}

.timetable-cell--has-session[role="button"]:hover {
  background: rgba(90, 92, 98, 0.95);
  border-color: var(--accent);
  box-shadow: 0 4px 20px rgba(0, 0, 0, 0.3);
}

.timetable-cell--has-session[role="button"]:focus {
  outline: 2px solid var(--accent);
  outline-offset: 2px;
}

.timetable-cell--has-session:not([role="button"]) {
  background: rgba(70, 72, 78, 0.92);
  color: var(--text);
  font-weight: 500;
  border: 1px solid var(--border-strong);
  box-shadow: var(--shadow);
}

/* ========== SPEAKERS ========== */
.section-speakers {
  position: relative;
  background-color: #1c1c22;
  overflow: hidden;
}

.section-speakers::before {
  content: "";
  position: absolute;
  inset: 0;
  background-image:
    linear-gradient(to bottom, rgba(0, 0, 0, 0.45), rgba(0, 0, 0, 0.35)),
    url("../img/bg_speaker_sec.png");
  background-size: cover;
  background-position: center center;
  background-repeat: no-repeat;
  opacity: 0.55;
  z-index: 0;
  pointer-events: none;
}

/* スピーカー下部の境目ぼかし（アーカイブへの滑らかな繋がり） */
.section-speakers::after {
  content: "";
  position: absolute;
  inset: 0;
  pointer-events: none;
  background-image:
    linear-gradient(to bottom, rgba(0, 0, 0, 0.55) 0%, transparent 18%),
    linear-gradient(to top, transparent 50%, rgba(0, 0, 0, 0.4) 75%, rgba(0, 0, 0, 0.85) 100%);
  background-size: 100% 100%, 100% 100%;
  background-position: top, bottom;
  background-repeat: no-repeat;
  z-index: 1;
}

.section-speakers .container {
  position: relative;
  z-index: 2;
}

.speakers-subheading .speakers-note {
  margin-left: 1em;
  font-size: 0.6em;
  font-weight: 500;
  color: rgba(255, 255, 255, 0.7);
  letter-spacing: 0.02em;
  vertical-align: middle;
}

.speakers-subheading {
  margin: 0 0 1rem 0;
  padding: 0.5rem 0 0.5rem 1rem;
  font-size: 1.375rem;
  font-weight: 700;
  color: #fff;
  letter-spacing: 0.06em;
  border-left: 4px solid var(--accent);
  background: rgba(255, 255, 255, 0.06);
  border-radius: 0 4px 4px 0;
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
}

.speakers-subheading:not(:first-of-type) {
  margin-top: 2.5rem;
}

.speakers-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 1.25rem;
}

.speaker-card {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  background: var(--bg-card);
  padding: 1rem 0.75rem 0.5rem 0.75rem;
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: var(--shadow);
  cursor: pointer;
  transition: box-shadow 0.2s, border-color 0.2s, background 0.2s;
}

.speaker-card:hover {
  border-color: var(--accent);
  background: var(--bg-card-hover);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.4);
}

/* 登壇者カード：グレー背景に映えるカードスタイル */
.section-speakers .speaker-card {
  background: rgba(38, 38, 44, 0.85);
  border-color: rgba(255, 255, 255, 0.08);
  box-shadow: 0 4px 24px rgba(0, 0, 0, 0.35);
}
.section-speakers .speaker-card:hover {
  background: rgba(48, 48, 54, 0.92);
  border-color: var(--accent);
  box-shadow: 0 8px 32px rgba(0, 0, 0, 0.45);
}

.speaker-avatar {
  flex-shrink: 0;
  width: 100px;   /* 392×588（2:3）に合わせた表示 */
  height: 150px;
  margin-bottom: 0.75rem;
  border-radius: var(--radius);
  font-size: 85%; /* 画像なし時のalt表示を15%小さく */
  line-height: 150px; /* 画像なし時のaltを上下中央に */
  text-align: left;
  overflow: hidden;
  background: var(--border);
  display: flex;
  align-items: center;
  justify-content: start;
}

.speaker-avatar img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center top;
  display: block;
}

.speaker-body {
  min-width: 0;
  width: 100%;
}

.speaker-name {
  margin: 0 0 0.25rem 0;
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text);
}

.speaker-name-en {
  display: block;
  font-size: 1rem;
  font-weight: 400;
  color: var(--text-muted);
}

.speaker-department {
  margin: 0 0 0.15rem 0;
  font-size: 0.95rem;
  font-weight: 500;
  color: var(--text-muted);
}

.speaker-department:empty {
  display: none;
}

.speaker-role {
  margin: 0 0 0.35rem 0;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--accent);
}

.speaker-card .speaker-bio {
  display: none;
}

.speaker-credentials {
  margin: 0.5rem 0 0 0;
  font-size: 1.4rem;
  line-height: 1.7;
  color: var(--text);
  opacity: 0.9;
}

.speaker-card .speaker-credentials {
  display: none;
}

/* ========== MESSAGE (旧ARCHIVE) ========== */
#message.section-archive {
  position: relative;
  background-color: #000;
  overflow: visible;
}

/* 背景画像（お問い合わせセクションまで被せる）＋上部境目ぼかし＋透け具合統一オーバーレイ */
#message.section-archive::before {
  content: "";
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  bottom: -400px;
  pointer-events: none;
  z-index: 0;
  background-image:
    linear-gradient(to bottom, rgba(0, 0, 0, 0.9) 0%, rgba(0, 0, 0, 0.4) 50%, transparent 100%),
    linear-gradient(to bottom, rgba(0, 0, 0, 0.65), rgba(0, 0, 0, 0.65)),
    url("../img/bg_archive_sec.png");
  background-size: 100% 140px, 100% 100%, cover;
  background-position: top center, top left, center center;
  background-repeat: no-repeat, no-repeat, no-repeat;
}

.archive-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(380px, 1fr));
  gap: 2.5rem;
  margin-bottom: 1.5rem;
}

.archive-item {
  background: var(--bg-card);
  border-radius: var(--radius);
  overflow: hidden;
  box-shadow: var(--shadow);
  border: 1px solid var(--border);
}

.video-wrapper {
  position: relative;
  padding-bottom: 56.25%;
  height: 0;
  overflow: hidden;
  background: #000;
}

.video-wrapper iframe,
.video-wrapper video {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
}

.video-wrapper video {
  object-fit: contain;
}

.video-wrapper--coming-soon {
  background: var(--bg-sub);
}

.video-wrapper--coming-soon .coming-soon {
  position: absolute;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  margin: 0;
  font-size: 1.8rem;
  font-weight: 500;
  color: var(--text-muted);
}

.archive-caption {
  margin: 0;
  padding: 1.25rem 1.5rem;
  font-size: 1.7rem;
  font-weight: 500;
  color: var(--text);
}

.archive-note {
  margin: 0;
  font-size: 1.45rem;
  color: var(--text-muted);
  text-align: center;
}

.archive-note--link {
  margin-top: 2rem;
}

.archive-link {
  color: var(--accent);
  text-decoration: none;
  font-weight: 600;
  border-bottom: 1px solid transparent;
  transition: color 0.2s, border-color 0.2s;
}

.archive-link:hover {
  color: var(--accent-hover);
  border-bottom-color: var(--accent-hover);
}

/* ========== CONTACT ========== */
#contact.section-contact {
  position: relative;
  background-color: #000;
  background-image:
    linear-gradient(to bottom, transparent 0%, rgba(0, 0, 0, 0.4) 35%, rgba(0, 0, 0, 0.85) 65%, #000 100%),
    linear-gradient(105deg, transparent 55%, rgba(0, 120, 135, 0.12) 78%, transparent 95%),
    radial-gradient(ellipse 70% 40% at 80% 20%, rgba(0, 120, 135, 0.1) 0%, transparent 55%);
}

.contact-lead {
  text-align: center;
  margin: 0 0 4rem 0;
  font-size: 1.8rem;
  line-height: 1.85;
  color: var(--text);
}

.contact-cta {
  display: block;
  width: fit-content;
  margin: 0 auto 3.5rem;
  padding: 1.35rem 2.75rem;
  font-size: 1.75rem;
  font-weight: 600;
  color: var(--bg-base);
  background: var(--accent);
  border-radius: 4px;
  text-decoration: none;
  text-align: center;
  transition: background 0.2s;
}

.contact-cta:hover {
  background: var(--accent-hover);
}

/* 昨年度ページへの誘導リンク（CONTACTセクション内） */
.contact-past {
  text-align: center;
  margin: 0;
  font-size: 0.95rem;
}

.contact-past a {
  color: rgba(255, 255, 255, 0.8);
  text-decoration: none;
  transition: color 0.2s;
}

.contact-past a:hover {
  color: #fff;
}

/* ========== Footer ========== */
.footer {
  background: var(--bg-base);
  color: var(--text);
  padding: 1rem;
  text-align: center;
  border-top: 1px solid var(--border);
}

/* 利用規約・プライバシーポリシーリンク（参考画像に準拠：横並び・区切り線・薄いグレー） */
.footer-legal-links {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  gap: 0.75rem 1rem;
  margin-bottom: 1rem;
}

.footer-legal-links a {
  color: var(--text-muted);
  text-decoration: none;
  font-size: 1rem;
  transition: color 0.2s;
}

.footer-legal-links a:hover {
  color: var(--text);
}

.footer-legal-sep {
  color: var(--text-muted);
  opacity: 0.6;
  font-size: 0.8rem;
  user-select: none;
}

.footer-copy {
  margin: 0;
  font-size: 0.8rem;
  opacity: 0.85;
}

/* ========== Modal（登壇者PROFILE） ========== */
.modal {
  position: fixed;
  inset: 0;
  z-index: 1000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 1rem;
  visibility: hidden;
  opacity: 0;
  transition: visibility 0.2s, opacity 0.2s;
}

.modal.is-open {
  visibility: visible;
  opacity: 1;
}

.modal-overlay {
  position: absolute;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  cursor: pointer;
}

.modal-box {
  position: relative;
  width: 100%;
  max-width: 560px;  /* 800px の 70%（30%減） */
  max-height: 90vh;
  overflow-y: auto;
  background: var(--bg-card);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  box-shadow: 0 24px 64px rgba(0, 0, 0, 0.6);
  padding: 2.5rem 2.5rem 3rem;
}

.modal-close {
  position: absolute;
  top: 1rem;
  right: 1rem;
  width: 2.5rem;
  height: 2.5rem;
  padding: 0;
  font-size: 2.25rem;
  line-height: 1;
  color: var(--text-muted);
  background: none;
  border: none;
  cursor: pointer;
  border-radius: var(--radius);
  transition: color 0.2s, background 0.2s;
}

.modal-close:hover {
  color: var(--text);
  background: var(--accent-bg);
}

.modal-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
}

.modal-avatar {
  flex-shrink: 0;
  width: 200px;   /* 392×588（2:3）に合わせた表示 */
  height: 300px;
  margin-bottom: 1.5rem;
  border-radius: var(--radius);
  overflow: hidden;
  background: var(--border);
}

.modal-avatar img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center top;
  display: block;
}

.modal-body {
  min-width: 0;
  width: 100%;
}

.modal-name {
  margin: 0 0 0.35rem 0;
  font-size: 2.25rem;
  font-weight: 700;
  color: var(--text);
}

.modal-name .speaker-name-en {
  display: block;
  font-size: 1.45rem;
  font-weight: 400;
  color: var(--text-muted);
}

.modal-department {
  margin: 0 0 0.25rem 0;
  font-size: 1.45rem;
  font-weight: 500;
  color: var(--text-muted);
}

.modal-department:empty {
  display: none;
}

.modal-role {
  margin: 0 0 1rem 0;
  font-size: 1.55rem;
  font-weight: 600;
  color: var(--accent);
}

.modal-bio {
  margin: 0;
  font-size: 1.55rem;
  line-height: 1.8;
  color: var(--text);
  text-align: left;
}

.modal-credentials {
  margin: 0.86rem 0 0 0;
  font-size: 1.4rem;
}

/* 個別セッション登壇者モーダル */
.modal--session .modal-box {
  max-width: 560px;  /* 800px の 70%（30%減） */
}

.session-modal-title {
  margin: 0 0 0.5rem 0;
  font-size: 2.28rem;  /* 2.85rem の 20% 減 */
  font-weight: 700;
  color: var(--text);
  text-align: center;
  white-space: pre-line;  /* \n で改行を反映 */
}

.session-modal-content {
  display: flex;
  flex-direction: column;
  gap: 2rem;
}

.session-group {
  margin: 0;
}

/* ① タイトル */
.session-group-title {
  margin: 0 0 0.5rem 0;
  font-size: 1.9rem;
  font-weight: 700;
  color: var(--text);
  line-height: 1.4;
}

/* ② サブタイトル */
.session-group-subtitle {
  margin: 0 0 1rem 0;
  font-size: 1.45rem;
  font-weight: 500;
  color: var(--text-muted);
  line-height: 1.5;
  text-align: center;
}

/* ③ 内容ラベル */
.session-group-content-label {
  margin: 3rem 0 0.4rem 0;
  font-size: 1.35rem;
  font-weight: 600;
  color: var(--text);
}

/* ③ 詳細 */
.session-group-description {
  margin: 0 0 1.5rem 0;
  font-size: 1.35rem;
  color: var(--text-muted);
  line-height: 1.7;
  padding: 0 1rem;
  white-space: pre-line;
}

.session-speakers-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 0.75rem;
}

.session-speaker-item {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.75rem;
  padding: 0.6rem 0.85rem;
  background: var(--bg-section);
  border-radius: var(--radius);
  border: 1px solid var(--border);
  cursor: pointer;
  transition: background-color 0.2s ease, border-color 0.2s ease;
  min-width: 0;
  text-align: center;
}

.session-speaker-item:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-strong);
}

.session-speaker-item .session-speaker-avatar {
  flex-shrink: 0;
  width: 108px;   /* 72pxの50%増し */
  height: 162px;
  border-radius: 6px;
  overflow: hidden;
  background: var(--border);
  font-size: 85%;           /* 画像なし時の alt 表示をスピーカーセクションと同様に */
  line-height: 162px;       /* 画像なし時の alt を上下中央に */
  text-align: center;
  display: flex;
  align-items: center;
  justify-content: center;
}

.session-speaker-item .session-speaker-avatar img {
  width: 100%;
  height: 100%;
  object-fit: contain;
  object-position: center top;
  display: block;
}

.session-speaker-name {
  margin: 0;
  font-size: 1.55rem;
  font-weight: 600;
  color: var(--text);
}

.session-speaker-department {
  margin: 0.25rem 0 0 0;
  font-size: 0.95rem;  /* 1.35rem の 30% 減 */
  color: var(--text-muted);
}

/* ========== Responsive ========== */
/* iPad 縦・横（1024px 以下） */
@media (max-width: 1024px) {
  .container {
    max-width: min(1024px, 92%);
    padding: 0 2rem;
  }

  .section {
    padding: 4.5rem 0;
  }

  .section-heading {
    font-size: clamp(2.6rem, 5.5vw, 3.75rem);
  }

  .section-heading__en {
    font-size: clamp(3.5rem, 10vw, 6.5rem);
  }

  .speakers-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: 1.1rem;
  }

  .archive-grid {
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 2rem;
  }

  .timetable-info {
    margin: 1.5rem 0 6rem 0;
    font-size: clamp(1.1rem, 2vw, 1.45rem);
  }

  .contact-lead {
    font-size: 1.6rem;
    margin-bottom: 3rem;
  }

  .contact-cta {
    padding: 1.2rem 2.25rem;
    font-size: 1.55rem;
  }

  .session-speakers-list {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* iPad 縦・タブレット（768px 以下） */
@media (max-width: 768px) {
  .container {
    padding: 0 1.5rem;
  }

  .timetable-scroll-outer {
    margin: 0 -1.5rem;
    padding: 0 1.5rem;
  }

  .hero {
    padding: 4rem 1.5rem 5rem;
    min-height: auto;
  }

  .hero-event-name {
    font-size: clamp(3.25rem, 12vw, 4.25rem);
  }

  .hero-overview {
    margin-top: 3.5rem;
    font-size: clamp(1.25rem, 3.5vw, 1.5rem);
  }

  .section {
    padding: 4rem 0;
  }

  .section-heading {
    font-size: clamp(2.4rem, 7.8vw, 3.25rem);
  }

  .section-heading__en {
    font-size: clamp(3rem, 18vw, 5rem);
  }

  .section-lead {
    font-size: 1.5rem;
    margin-bottom: 2rem;
  }

  .speakers-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: 1rem;
  }

  .speaker-card {
    padding: 1rem 0.75rem 0.5rem 0.75rem;
  }

  .speaker-avatar {
    width: 80px;
    height: 120px;
    margin-bottom: 0.6rem;
    line-height: 120px;
  }

  .speaker-name {
    font-size: 1.2rem;
  }

  .speaker-name-en {
    font-size: 0.9rem;
  }

  .speaker-department {
    font-size: 0.88rem;
  }

  .speaker-role {
    font-size: 0.85rem;
  }

  .archive-grid {
    grid-template-columns: 1fr;
    gap: 1.75rem;
    margin-bottom: 1.25rem;
  }

  .archive-caption {
    font-size: 1.5rem;
    padding: 1rem 1.25rem;
  }

  .archive-note,
  .archive-note--link {
    font-size: 1.3rem;
    margin-top: 1.5rem;
  }

  .modal-box {
    padding: 2rem 1.5rem 2.5rem;
    max-width: 92vw;
  }

  .modal-avatar {
    width: 180px;
    height: 270px;
    margin-bottom: 1.25rem;
  }

  .modal-name {
    font-size: 2rem;
  }

  .modal-department,
  .modal-role,
  .modal-bio,
  .modal-credentials {
    font-size: 1.35rem;
  }

  .session-modal-title {
    font-size: 2rem;
  }

  .session-group-title {
    font-size: 1.7rem;
  }
}

/* スマホ大（667px 以下） */
@media (max-width: 667px) {
  html {
    font-size: 70%;
  }

  .container {
    padding: 0 1.25rem;
  }

  .timetable-scroll-outer {
    margin: 0 -1.25rem;
    padding: 0 1.25rem;
  }

  .hero {
    padding: 3rem 1.25rem 4rem;
  }

  .hero-event-name {
    font-size: clamp(2.75rem, 11vw, 3.5rem);
  }

  .hero-message-line1 {
    font-size: clamp(1.75rem, 5vw, 2.25rem);
  }

  .hero-message-line1 br {
    display: block;
  }

  .hero-organizer {
    padding: 1rem 1.5rem;
    margin-top: 1.5rem;
    font-size: 75%;
  }

  .hero-overview {
    margin-top: 2.5rem;
    font-size: 1.2rem;
  }

  .section {
    padding: 3.5rem 0;
  }

  .section-heading {
    font-size: clamp(2.1rem, 6.5vw, 2.85rem);
    margin-bottom: 1.5rem;
  }

  .section-heading__en {
    font-size: clamp(2.5rem, 14vw, 4rem);
  }

  .timetable-info {
    margin: 1rem 0 5rem 0;
    font-size: 1.1rem;
  }

  .timetable-layout {
    font-size: 0.9rem;
  }

  .timetable-cell--has-session {
    font-size: 0.8rem;
  }

  .speakers-grid {
    gap: 0.85rem;
  }

  .speaker-avatar {
    width: 72px;
    height: 108px;
    margin-bottom: 0.5rem;
    line-height: 108px;
  }

  .speaker-name {
    font-size: 1.1rem;
  }

  .speaker-name-en {
    font-size: 0.8rem;
  }

  .speaker-department {
    font-size: 0.82rem;
  }

  .contact-lead {
    font-size: 1.4rem;
    margin-bottom: 2.5rem;
  }

  .contact-cta {
    padding: 1rem 2rem;
    font-size: 1.4rem;
    margin-bottom: 2.5rem;
  }

  .footer {
    padding: 0.5rem 1rem;
  }

  .footer-legal-links {
    gap: 0.35rem 0.6rem;
    margin-bottom: 0.5rem;
  }

  .footer-legal-links a,
  .footer-copy {
    font-size: 0.9rem;
  }

  .modal-box {
    padding: 1.75rem 1.25rem 2rem;
  }

  .modal-avatar {
    width: 160px;
    height: 240px;
    margin-bottom: 1rem;
  }

  .modal-name {
    font-size: 1.75rem;
  }

  .modal-department,
  .modal-role {
    font-size: 1.2rem;
  }

  .modal-bio,
  .modal-credentials {
    font-size: 1.2rem;
  }

  .session-speakers-list {
    grid-template-columns: 1fr;
  }

  .session-speaker-item .session-speaker-avatar {
    width: 96px;
    height: 144px;
    line-height: 144px;
  }
}

/* スマホ小（375px 以下） */
@media (max-width: 375px) {
  html {
    font-size: 65%;
  }

  .container {
    padding: 0 1rem;
  }

  .timetable-scroll-outer {
    margin: 0 -1rem;
    padding: 0 1rem;
  }

  .hero {
    padding: 2.5rem 1rem 3.5rem;
  }

  .hero-event-name {
    font-size: clamp(2.35rem, 14vw, 2.85rem);
  }

  .hero-message-line1 {
    font-size: clamp(1.5rem, 6vw, 1.9rem);
  }

  .hero-organizer {
    padding: 0.85rem 1.2rem;
    font-size: 85%;
  }

  .hero-overview {
    font-size: 1.1rem;
    line-height: 1.8;
  }

  .section {
    padding: 3rem 0;
  }

  .section-heading {
    font-size: clamp(1.9rem, 8vw, 2.5rem);
    margin-bottom: 1.25rem;
  }

  .section-heading__en {
    font-size: clamp(2.2rem, 16vw, 3.5rem);
  }

  .timetable-info {
    margin: 0.75rem 0 4rem 0;
    font-size: 1rem;
  }

  .timetable-venue {
    font-size: 0.8em;
  }

  .timetable-time {
    font-size: 0.9rem;
  }

  .speakers-grid {
    grid-template-columns: 1fr;
    gap: 0.75rem;
  }

  .speaker-card {
    flex-direction: row;
    text-align: left;
    align-items: flex-start;
    padding: 0.85rem 1rem;
  }

  .speaker-avatar {
    width: 64px;
    height: 96px;
    margin-bottom: 0;
    margin-right: 1rem;
    flex-shrink: 0;
    line-height: 96px;
  }

  .speaker-body {
    min-width: 0;
  }

  .speaker-name {
    font-size: 1.05rem;
  }

  .speaker-name-en {
    font-size: 0.75rem;
  }

  .speaker-department {
    font-size: 0.8rem;
  }

  .archive-caption {
    font-size: 1.35rem;
    padding: 0.9rem 1rem;
  }

  .archive-note,
  .archive-note--link {
    font-size: 1.15rem;
  }

  .contact-lead {
    font-size: 1.25rem;
    margin-bottom: 2rem;
  }

  .contact-cta {
    display: block;
    width: 100%;
    max-width: 320px;
    margin-left: auto;
    margin-right: auto;
    padding: 0.9rem 1.5rem;
    font-size: 1.25rem;
  }

  .footer {
    padding: 0.4rem 1rem;
  }

  .footer-legal-links {
    flex-direction: column;
    gap: 0.2rem;
    margin-bottom: 0.35rem;
  }

  .footer-legal-sep {
    display: none;
  }

  .modal-box {
    padding: 1.5rem 1rem 1.75rem;
    max-height: 85vh;
  }

  .modal-content {
    flex-direction: column;
  }

  .modal-avatar {
    width: 140px;
    height: 210px;
    margin-bottom: 0.85rem;
  }

  .modal-name {
    font-size: 1.55rem;
  }

  .modal-department,
  .modal-role,
  .modal-bio,
  .modal-credentials {
    font-size: 1.1rem;
  }

  .session-modal-title {
    font-size: 1.75rem;
  }

  .session-group-title {
    font-size: 1.5rem;
  }

  .session-group-subtitle {
    font-size: 1.25rem;
  }

  .session-speaker-item .session-speaker-avatar {
    width: 80px;
    height: 120px;
    line-height: 120px;
  }
}