/* ===== リセット・共通 ===== */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Hiragino Kaku Gothic ProN', 'Noto Sans JP', sans-serif;
  background: #fdf6f4;
  color: #2d2d2d;
  line-height: 1.6;
  min-height: 100vh;
}

.sp-only { display: none; }

/* ===== ログインページ ===== */
.login-page {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100vh;
  background: linear-gradient(135deg, #f8e8e5 0%, #f0d4cc 100%);
}

.login-container {
  background: #fff;
  border-radius: 16px;
  padding: 48px 40px;
  width: 100%;
  max-width: 400px;
  box-shadow: 0 8px 40px rgba(0,0,0,0.1);
  text-align: center;
}

.login-logo {
  font-size: 28px;
  font-weight: 800;
  color: #c97b6a;
  letter-spacing: 3px;
  margin-bottom: 24px;
}

.login-title {
  font-size: 18px;
  font-weight: 700;
  color: #2d2d2d;
  margin-bottom: 6px;
  line-height: 1.5;
}

.login-subtitle {
  font-size: 13px;
  color: #999;
  margin-bottom: 32px;
}

.login-form {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.login-input {
  width: 100%;
  padding: 14px 16px;
  border: 2px solid #e8ddd9;
  border-radius: 10px;
  font-size: 15px;
  outline: none;
  transition: border-color 0.2s;
  background: #fdfaf9;
}

.login-input:focus { border-color: #c97b6a; }

.login-btn {
  width: 100%;
  padding: 14px;
  background: #4a90d9;
  color: #fff;
  border: none;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 700;
  cursor: pointer;
  transition: opacity 0.2s;
}

.login-btn:hover { opacity: 0.88; }

.login-error {
  color: #e53935;
  font-size: 13px;
  margin-top: 4px;
}

/* ===== ヘッダー ===== */
.header {
  background: #3a3a3a;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-inner {
  max-width: 1200px;
  margin: 0 auto;
  padding: 0 24px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.header-logo {
  font-size: 20px;
  font-weight: 800;
  color: #fff;
  letter-spacing: 3px;
  text-decoration: none;
}

.header-nav {
  display: flex;
  align-items: center;
  gap: 16px;
}

.header-name {
  font-size: 13px;
  color: #ccc;
}

.logout-btn {
  background: none;
  border: 1px solid #666;
  border-radius: 6px;
  padding: 5px 14px;
  font-size: 12px;
  color: #ccc;
  cursor: pointer;
  transition: all 0.2s;
}

.logout-btn:hover { border-color: #ccc; color: #fff; }

/* ===== ダッシュボード ===== */
.main {
  padding: 40px 24px 80px;
}

.container {
  max-width: 1100px;
  margin: 0 auto;
}

.course-title {
  font-size: 22px;
  font-weight: 700;
  color: #2d2d2d;
  text-align: center;
  margin-bottom: 24px;
  line-height: 1.4;
}

/* 全体進捗 */
.overall-progress {
  max-width: 500px;
  margin: 0 auto 40px;
  text-align: center;
}

.overall-progress-bar-wrap {
  background: #e8ddd9;
  border-radius: 100px;
  height: 8px;
  overflow: hidden;
  margin-bottom: 8px;
}

.overall-progress-bar {
  height: 100%;
  background: #4a90d9;
  border-radius: 100px;
  width: 0%;
  transition: width 0.5s ease;
}

.overall-progress-text {
  font-size: 13px;
  color: #999;
}

/* フェーズセクション */
.phase-section {
  margin-bottom: 48px;
}

.phase-label {
  font-size: 14px;
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 4px;
  display: inline-block;
  margin-bottom: 20px;
}

.phase-label-0 { background: #fff3e0; color: #e65100; }
.phase-label-1 { background: #e8f5e9; color: #2e7d32; }
.phase-label-2 { background: #e3f2fd; color: #1565c0; }
.phase-label-3 { background: #fce4ec; color: #b71c1c; }

/* カードグリッド */
.cards-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 24px;
}

/* カード */
.card {
  background: #fff;
  border-radius: 12px;
  overflow: hidden;
  box-shadow: 0 2px 12px rgba(0,0,0,0.07);
  transition: transform 0.2s, box-shadow 0.2s;
}

.card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 24px rgba(0,0,0,0.12);
}

/* カードサムネイル */
.card-thumb {
  width: 100%;
  aspect-ratio: 16/9;
  display: flex;
  align-items: flex-end;
  padding: 10px 12px;
}

.card-thumb-0a { background: url('https://images.pexels.com/photos/7947838/pexels-photo-7947838.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1a { background: url('https://images.pexels.com/photos/10902646/pexels-photo-10902646.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1b { background: url('https://images.pexels.com/photos/6914632/pexels-photo-6914632.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1c { background: url('https://images.pexels.com/photos/3862374/pexels-photo-3862374.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1d { background: url('https://images.pexels.com/photos/7947698/pexels-photo-7947698.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1e { background: url('https://images.pexels.com/photos/7688106/pexels-photo-7688106.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1f { background: url('https://images.pexels.com/photos/7877016/pexels-photo-7877016.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2a { background: url('https://images.pexels.com/photos/15635241/pexels-photo-15635241.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2b { background: url('https://images.pexels.com/photos/3850265/pexels-photo-3850265.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2c { background: url('https://images.pexels.com/photos/4087400/pexels-photo-4087400.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2d { background: url('https://images.pexels.com/photos/106344/pexels-photo-106344.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2e { background: url('https://images.pexels.com/photos/7368/startup-photos.jpg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a { background: url('https://images.pexels.com/photos/6424590/pexels-photo-6424590.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3b { background: url('https://images.pexels.com/photos/7054417/pexels-photo-7054417.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3c { background: url('https://images.pexels.com/photos/5971288/pexels-photo-5971288.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3d { background: url('https://images.pexels.com/photos/16094056/pexels-photo-16094056.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3e { background: url('https://images.pexels.com/photos/7792845/pexels-photo-7792845.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-sheet { background: url('https://images.pexels.com/photos/8962460/pexels-photo-8962460.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1a2 { background: url('https://images.pexels.com/photos/590044/pexels-photo-590044.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1d2 { background: url('https://images.pexels.com/photos/6801648/pexels-photo-6801648.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1e2 { background: url('https://images.pexels.com/photos/3912478/pexels-photo-3912478.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1f2 { background: url('https://images.pexels.com/photos/7841477/pexels-photo-7841477.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1b2 { background: url('https://images.pexels.com/photos/29521529/pexels-photo-29521529.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-1c2 { background: url('https://images.pexels.com/photos/4458210/pexels-photo-4458210.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2b2 { background: url('https://images.pexels.com/photos/2388936/pexels-photo-2388936.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2c2 { background: url('https://images.pexels.com/photos/6170653/pexels-photo-6170653.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-2e2 { background: url('https://images.pexels.com/photos/1181311/pexels-photo-1181311.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a2 { background: url('https://images.pexels.com/photos/4973899/pexels-photo-4973899.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a3 { background: url('https://images.pexels.com/photos/5474292/pexels-photo-5474292.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a4 { background: url('https://images.pexels.com/photos/12244847/pexels-photo-12244847.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a5 { background: url('https://images.pexels.com/photos/6804078/pexels-photo-6804078.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }
.card-thumb-3a6 { background: url('https://images.pexels.com/photos/6610212/pexels-photo-6610212.jpeg?auto=compress&cs=tinysrgb&w=600') center/cover no-repeat; }

.card-type-badge {
  display: inline-block;
  padding: 3px 10px;
  border-radius: 4px;
  font-size: 11px;
  font-weight: 700;
}

.badge-video { background: rgba(255,255,255,0.9); color: #e65100; }
.badge-sheet { background: rgba(255,255,255,0.9); color: #2e7d32; }
.badge-doc   { background: rgba(255,255,255,0.9); color: #c97b6a; }

.card-body {
  padding: 14px 16px 16px;
}

.card-title {
  font-size: 14px;
  font-weight: 600;
  color: #333;
  line-height: 1.5;
  margin-bottom: 12px;
  min-height: 42px;
}

.card-progress-wrap {
  background: #eee;
  border-radius: 100px;
  height: 6px;
  overflow: hidden;
  margin-bottom: 12px;
}

.card-progress-bar {
  height: 100%;
  background: #4a90d9;
  border-radius: 100px;
  width: 0%;
  transition: width 0.4s ease;
}

.card.completed .card-progress-bar { width: 100%; }

.card-footer {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.card-btn {
  display: inline-block;
  padding: 8px 20px;
  background: #4a90d9;
  color: #fff;
  border-radius: 6px;
  font-size: 13px;
  font-weight: 700;
  text-decoration: none;
  transition: opacity 0.2s;
}

.card-btn:hover { opacity: 0.85; }

.card-pct {
  font-size: 12px;
  color: #aaa;
}

.card.completed .card-pct { color: #4a90d9; font-weight: 700; }

/* カードのレッスンID */
.card-lesson-id {
  display: inline-block;
  background: #f0e8e5;
  color: #a05040;
  font-size: 11px;
  font-weight: 700;
  padding: 1px 6px;
  border-radius: 3px;
  margin-right: 6px;
  vertical-align: middle;
  letter-spacing: 0.5px;
}

/* ワークブックセクション */
.workbook-section {
  margin-top: 16px;
  margin-bottom: 48px;
}

.workbook-banner {
  background: #fff;
  border: 2px solid #e8ddd9;
  border-radius: 16px;
  padding: 40px 36px;
  text-align: center;
}

.workbook-icon {
  font-size: 11px;
  font-weight: 800;
  letter-spacing: 4px;
  color: #c97b6a;
  margin-bottom: 8px;
}

.workbook-title {
  font-size: 22px;
  font-weight: 700;
  color: #2d2d2d;
  margin-bottom: 12px;
}

.workbook-desc {
  font-size: 14px;
  color: #777;
  line-height: 1.8;
  margin-bottom: 28px;
}

.workbook-phases {
  display: flex;
  gap: 20px;
  justify-content: center;
  margin-bottom: 32px;
  text-align: left;
}

.workbook-phase {
  background: #fdf8f6;
  border-radius: 10px;
  padding: 16px 20px;
  flex: 1;
  max-width: 260px;
}

.workbook-phase-label {
  display: inline-block;
  font-size: 11px;
  font-weight: 700;
  padding: 3px 10px;
  border-radius: 4px;
  margin-bottom: 10px;
}

.wb-phase-0 { background: #fff3e0; color: #e65100; }
.wb-phase-1 { background: #e8f5e9; color: #2e7d32; }
.wb-phase-2 { background: #e3f2fd; color: #1565c0; }
.wb-phase-3 { background: #fce4ec; color: #b71c1c; }

.workbook-sheet-list {
  list-style: none;
  padding: 0;
}

.workbook-sheet-list li {
  font-size: 13px;
  color: #555;
  padding: 4px 0;
  line-height: 1.5;
}

.workbook-sheet-list li::before {
  content: '';
  display: inline-block;
  width: 6px;
  height: 6px;
  background: #c97b6a;
  border-radius: 50%;
  margin-right: 8px;
  vertical-align: middle;
}

.workbook-btn {
  display: inline-block;
  padding: 14px 40px;
  background: #c97b6a;
  color: #fff;
  border-radius: 10px;
  font-size: 15px;
  font-weight: 700;
  text-decoration: none;
  transition: opacity 0.2s, transform 0.2s;
  box-shadow: 0 4px 16px rgba(201,123,106,0.3);
}

.workbook-btn:hover {
  opacity: 0.88;
  transform: translateY(-2px);
}

@media (max-width: 640px) {
  .workbook-phases { flex-direction: column; align-items: center; }
  .workbook-phase { max-width: 100%; width: 100%; }
  .workbook-banner { padding: 28px 20px; }
}

/* ===== レッスンページ ===== */
.lesson-page {
  background: #f8f8f8;
}

.lesson-layout {
  display: flex;
  min-height: calc(100vh - 56px);
}

/* サイドバー */
.sidebar {
  width: 260px;
  min-width: 260px;
  background: #fff;
  border-right: 1px solid #e8e8e8;
  padding: 24px 0;
  overflow-y: auto;
}

.sidebar-phase-name {
  font-size: 12px;
  font-weight: 700;
  color: #999;
  text-transform: uppercase;
  letter-spacing: 0.5px;
  padding: 0 20px 12px;
  border-bottom: 1px solid #f0f0f0;
  margin-bottom: 8px;
}

.sidebar-list {
  list-style: none;
}

.sidebar-item a {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 10px 20px;
  text-decoration: none;
  color: #555;
  font-size: 13px;
  line-height: 1.5;
  transition: background 0.15s;
}

.sidebar-item a:hover { background: #f8f4ff; }

.sidebar-item.current a {
  background: #eef4fb;
  color: #1565c0;
  font-weight: 600;
}

/* ラジオ風アイコン */
.sidebar-radio {
  width: 16px;
  height: 16px;
  min-width: 16px;
  border-radius: 50%;
  border: 2px solid #ccc;
  margin-top: 2px;
  transition: all 0.2s;
}

.sidebar-radio.checked {
  background: #4a90d9;
  border-color: #4a90d9;
}

.sidebar-item.current .sidebar-radio {
  border-color: #4a90d9;
}

/* レッスンメイン */
.lesson-main {
  flex: 1;
  padding: 32px 48px 80px;
  max-width: 860px;
}

/* パンくず */
.breadcrumb {
  font-size: 12px;
  color: #aaa;
  margin-bottom: 20px;
}

.breadcrumb a {
  color: #4a90d9;
  text-decoration: none;
}

.breadcrumb a:hover { text-decoration: underline; }

/* レッスンヘッダー */
.lesson-header {
  display: flex;
  align-items: center;
  gap: 12px;
  margin-bottom: 28px;
  padding-bottom: 20px;
  border-bottom: 1px solid #e8e8e8;
}

.lesson-badge {
  display: inline-block;
  padding: 4px 12px;
  border-radius: 4px;
  font-size: 12px;
  font-weight: 700;
  white-space: nowrap;
}

.lesson-title {
  font-size: 22px;
  font-weight: 700;
  color: #2d2d2d;
  line-height: 1.4;
}

/* コンテンツエリア */
.lesson-content-area {
  min-height: 200px;
  margin-bottom: 48px;
}

/* Googleドライブボタン */
.drive-btn {
  display: inline-block;
  padding: 16px 32px;
  background: #4a90d9;
  color: #fff;
  border-radius: 10px;
  font-size: 16px;
  font-weight: 700;
  text-decoration: none;
  transition: opacity 0.2s, transform 0.2s;
  box-shadow: 0 4px 16px rgba(74,144,217,0.3);
}

.drive-btn:hover {
  opacity: 0.88;
  transform: translateY(-2px);
}

/* テキストレッスン用スタイル */
.lesson-text-content { margin-top: 28px; }
.lesson-text-intro { color: #555; margin-bottom: 24px; line-height: 1.8; }

.security-item {
  background: #fff;
  border: 1px solid #f0e0da;
  border-left: 4px solid #c97b6a;
  border-radius: 8px;
  padding: 20px 24px;
  margin-bottom: 20px;
}
.security-title {
  font-size: 16px;
  font-weight: 700;
  color: #3d2520;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 10px;
}
.security-num {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 28px;
  height: 28px;
  padding: 0 8px;
  background: #c97b6a;
  color: #fff;
  border-radius: 14px;
  font-size: 12px;
  font-weight: 700;
  flex-shrink: 0;
}
.security-item p { color: #444; line-height: 1.8; margin-bottom: 10px; }
.security-item p:last-child { margin-bottom: 0; }
.security-item code {
  background: #fdeee9;
  color: #a05040;
  padding: 2px 6px;
  border-radius: 4px;
  font-family: 'Courier New', monospace;
  font-size: 13px;
}
.security-item pre {
  background: #1e1e2e;
  color: #cdd6f4;
  padding: 12px 16px;
  border-radius: 6px;
  overflow-x: auto;
  margin: 10px 0;
  font-size: 13px;
  line-height: 1.6;
}
.security-item pre code { background: none; color: inherit; padding: 0; font-size: inherit; }
.terminal-note {
  background: #fff8f0;
  border: 1px solid #f5d0bc;
  border-radius: 6px;
  padding: 10px 14px;
  font-size: 13px;
  color: #7a4030;
  margin-top: 10px !important;
  line-height: 1.8;
}
.security-list { padding-left: 20px; color: #444; line-height: 2; }
.security-steps { padding-left: 20px; color: #444; line-height: 2; }
.security-table { width: 100%; border-collapse: collapse; font-size: 13px; margin: 10px 0; }
.security-table th { background: #fdf0ec; color: #3d2520; font-weight: 700; padding: 10px 12px; text-align: left; border-bottom: 2px solid #f0d0c4; }
.security-table td { padding: 10px 12px; border-bottom: 1px solid #fae8e4; color: #444; vertical-align: top; line-height: 1.7; }
.security-table tr:last-child td { border-bottom: none; }
.security-summary {
  background: #fdf0ec;
  border-radius: 8px;
  padding: 20px 24px;
  margin-top: 8px;
}
.security-summary h3 { font-size: 15px; color: #3d2520; margin-bottom: 12px; }
.security-block { margin-top: 12px; }

/* 準備中メッセージ */
.content-preparing {
  font-size: 15px;
  color: #aaa;
  line-height: 1.8;
  padding: 40px;
  background: #f8f8f8;
  border-radius: 10px;
  text-align: center;
}

/* ナビゲーションボタン */
.lesson-nav {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: 24px;
  border-top: 1px solid #e8e8e8;
}

.lesson-nav-btn {
  display: inline-block;
  padding: 10px 24px;
  border-radius: 6px;
  font-size: 14px;
  font-weight: 700;
  text-decoration: none;
  cursor: pointer;
  transition: opacity 0.2s;
  border: none;
}

.btn-prev {
  background: #f0f0f0;
  color: #555;
}

.btn-prev:hover { opacity: 0.75; }

.btn-done {
  background: #4a90d9;
  color: #fff;
  font-size: 15px;
  padding: 12px 36px;
}

.btn-done:hover { opacity: 0.85; }

.btn-done.done {
  background: #81b64c;
  cursor: default;
}

.btn-next {
  background: #4a90d9;
  color: #fff;
}

.btn-next:hover { opacity: 0.85; }

/* ===== レスポンシブ ===== */
@media (max-width: 900px) {
  .cards-grid { grid-template-columns: repeat(2, 1fr); gap: 16px; }
  .sidebar { width: 200px; min-width: 200px; }
  .lesson-main { padding: 24px 24px 60px; }
}

@media (max-width: 640px) {
  .sp-only { display: inline; }
  .main { padding: 24px 14px 60px; }
  .course-title { font-size: 18px; }
  .cards-grid { grid-template-columns: 1fr; gap: 14px; }
  .card-title { min-height: auto; }
  .header-name { display: none; }

  /* レッスンページ：サイドバーを非表示 */
  .lesson-layout { flex-direction: column; }
  .sidebar { width: 100%; min-width: auto; border-right: none; border-bottom: 1px solid #e8e8e8; padding: 16px 0; }
  .lesson-main { padding: 20px 16px 60px; }
  .lesson-title { font-size: 18px; }
  .lesson-nav { flex-direction: column; gap: 12px; }
  .lesson-nav-btn { width: 100%; text-align: center; }
}

/* ===== 関連シート セクション ===== */
.related-sheets {
  margin-top: 40px;
  padding: 24px;
  background: #fdf6f4;
  border: 1px solid #f0d4cc;
  border-radius: 10px;
}
.related-sheets-title {
  font-size: 17px;
  font-weight: 600;
  color: #c97b6a;
  margin-bottom: 8px;
}
.related-sheets-desc {
  font-size: 14px;
  color: #666;
  margin-bottom: 16px;
}
.related-sheets-list {
  display: flex;
  flex-direction: column;
  gap: 10px;
}
.related-sheet-btn {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 18px;
  background: #fff;
  border: 1px solid #e8c8bf;
  border-radius: 8px;
  color: #2d2d2d;
  text-decoration: none;
  transition: all 0.2s ease;
}
.related-sheet-btn:hover {
  background: #c97b6a;
  border-color: #c97b6a;
  color: #fff;
  transform: translateY(-1px);
  box-shadow: 0 2px 8px rgba(201, 123, 106, 0.25);
}
.related-sheet-name {
  font-size: 15px;
  font-weight: 500;
}
.related-sheet-arrow {
  font-size: 13px;
  color: #c97b6a;
  font-weight: 600;
}
.related-sheet-btn:hover .related-sheet-arrow {
  color: #fff;
}

@media (max-width: 640px) {
  .related-sheets { padding: 18px; }
  .related-sheet-btn { padding: 12px 14px; }
  .related-sheet-name { font-size: 14px; }
}