/* Top nav — 全页统一：全宽顶栏 + 固定最小高度 + 居中标题 */
.top-nav {
  position: sticky;
  top: 0;
  z-index: 50;
  box-sizing: border-box;
  width: 100vw;
  max-width: 100vw;
  margin-left: calc(50% - 50vw);
  margin-right: calc(50% - 50vw);
  min-height: var(--nav-bar-min-h);
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 0 max(16px, env(safe-area-inset-right, 0px)) 0
    max(16px, env(safe-area-inset-left, 0px));
  background: color-mix(in srgb, var(--palette-cream) 88%, var(--palette-bg));
  border-bottom: 1px solid var(--border);
  -webkit-backdrop-filter: blur(8px);
  backdrop-filter: blur(8px);
}

body:has(#page-home.is-active) .top-nav {
  background: color-mix(in srgb, var(--palette-cream) 88%, var(--palette-bg));
}

body:has(#page-verbs.is-active) .top-nav {
  background: color-mix(in srgb, var(--fr-tricolor-bleu) 72%, white 28%);
}

body:has(#page-quiz.is-active) .top-nav {
  background: color-mix(in srgb, var(--fr-tricolor-blanc) 82%, white 18%);
}

body:has(#page-scenario.is-active) .top-nav {
  background: var(--fr-tricolor-rouge);
}

.nav-back {
  position: absolute;
  left: max(16px, env(safe-area-inset-left, 0px));
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  flex-shrink: 0;
}

.nav-back[hidden] {
  display: none;
}

/* Site-wide back — arrow only; ink depth follows page surface */
.app-back {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 40px;
  width: 40px;
  height: 40px;
  padding: 0;
  font-size: 1.25rem;
  line-height: 1;
  font-weight: 500;
  color: color-mix(in srgb, var(--ink) 88%, transparent);
  background: transparent;
  border: none;
  border-radius: 8px;
  box-shadow: none;
  cursor: pointer;
  transition: color 0.15s ease, background 0.15s ease;
}

.app-back:hover {
  color: var(--ink);
  background: rgba(61, 42, 26, 0.08);
}

body:has(#page-scenario.is-active) .top-nav .app-back {
  color: color-mix(in srgb, var(--palette-cream) 92%, white);
}

body:has(#page-scenario.is-active) .top-nav .app-back:hover {
  color: #fff;
  background: rgba(255, 255, 255, 0.14);
}

/* In-page sub-nav: back left, title centered on same row */
.subpage-header {
  position: relative;
  display: block;
  min-height: 44px;
  margin-bottom: 16px;
}

.subpage-header--compact {
  min-height: 40px;
  margin-bottom: 12px;
}

.subpage-header__title {
  position: absolute;
  left: 0;
  right: 0;
  top: 50%;
  margin: 0;
  padding: 0 52px;
  transform: translateY(-50%);
  text-align: center;
  font-family: var(--serif);
  font-size: 1.35rem;
  font-weight: 700;
  letter-spacing: 0.02em;
  line-height: 1.2;
  color: var(--ink);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  pointer-events: none;
}

.subpage-header .app-back {
  position: relative;
  z-index: 1;
  margin: 0;
}

.nav-title {
  position: relative;
  z-index: 1;
  flex: 0 1 auto;
  width: 100%;
  max-width: 100%;
  margin: 0;
  padding: 0 4.5rem;
  font-family: var(--serif);
  font-size: var(--nav-title-size);
  font-weight: 700;
  letter-spacing: 0.01em;
  color: var(--ink);
  line-height: 1.1;
  text-align: center;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

body:has(#page-home.is-active) .nav-title {
  font-weight: 900;
  letter-spacing: -0.01em;
}

body:has(#page-home.is-active) .nav-back[hidden] + .nav-title {
  padding-left: 1rem;
  padding-right: 1rem;
}

.auth-nav-btn {
  position: absolute;
  right: max(16px, env(safe-area-inset-right, 0px));
  top: 50%;
  transform: translateY(-50%);
  z-index: 2;
  max-width: 42%;
  padding: 0 12px;
  height: 36px;
  font-size: 0.8rem;
  font-weight: 600;
  color: var(--ink);
  background: var(--card);
  border: 1px solid var(--border);
  border-radius: 10px;
  cursor: pointer;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  transition: box-shadow 0.15s;
}

.auth-nav-btn:hover { box-shadow: var(--shadow); }
.auth-nav-btn[hidden] { display: none; }

.auth-nav-btn--icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  max-width: 36px;
  padding: 0;
}

.auth-nav-btn--icon svg {
  width: 18px;
  height: 18px;
}

.auth-modal {
  max-width: 400px;
  width: calc(100% - 32px);
  padding: 22px 20px 20px;
}

.auth-modal-close {
  position: absolute;
  top: 12px;
  right: 12px;
  width: 32px;
  height: 32px;
  border: none;
  border-radius: 8px;
  background: transparent;
  font-size: 1.4rem;
  line-height: 1;
  cursor: pointer;
  color: var(--muted);
}

.auth-modal-title {
  margin: 0 0 12px;
  font-family: var(--serif);
  font-size: 1.5rem;
  font-weight: 700;
}

.auth-modal-hint {
  margin: 0 0 10px;
  font-size: 0.9rem;
  color: var(--text-muted);
}

.auth-message {
  margin: 0 0 12px;
  font-size: 0.85rem;
  color: var(--text-muted);
}

.auth-message--error { color: #b42318; }
.auth-message--ok { color: #027a48; }
.auth-message[hidden],
.auth-modal-hint[hidden],
.auth-tabs[hidden],
.auth-credentials[hidden] { display: none !important; }

.app-flash {
  position: fixed;
  top: 16px;
  left: 50%;
  z-index: 10000;
  max-width: min(92vw, 420px);
  padding: 12px 16px;
  border-radius: 12px;
  background: #ecfdf3;
  border: 1px solid #abefc6;
  color: #027a48;
  font-size: 0.9rem;
  font-weight: 500;
  line-height: 1.4;
  text-align: center;
  box-shadow: 0 8px 24px rgba(15, 23, 42, 0.12);
  transform: translateX(-50%);
}

.app-flash[hidden] { display: none !important; }

.auth-tabs {
  display: flex;
  gap: 8px;
  margin-bottom: 14px;
}

.auth-tab {
  flex: 1;
  height: 36px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  font-weight: 600;
  cursor: pointer;
}

.auth-tab.is-active {
  background: color-mix(in srgb, var(--fr-tricolor-bleu) 18%, white);
  border-color: color-mix(in srgb, var(--fr-tricolor-bleu) 40%, var(--border));
}

.auth-credentials { margin-bottom: 12px; }
.auth-input { margin-bottom: 10px; }

.auth-password-wrap {
  position: relative;
}

.auth-password-wrap .auth-input {
  padding-right: 40px;
}

.auth-password-toggle {
  position: absolute;
  right: 4px;
  top: 50%;
  transform: translateY(-50%);
  width: 34px;
  height: 34px;
  display: flex;
  align-items: center;
  justify-content: center;
  border: none;
  background: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0;
}

.auth-password-toggle:hover { color: var(--ink); }
.auth-password-toggle svg { width: 18px; height: 18px; }

.auth-panel { display: flex; flex-direction: column; gap: 10px; }
.auth-panel[hidden] { display: none; }

.auth-consent {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  margin: 0 0 2px;
  cursor: pointer;
}

.auth-consent input {
  flex-shrink: 0;
  width: 18px;
  height: 18px;
  margin: 2px 0 0;
  accent-color: var(--ink);
  cursor: pointer;
}

.auth-consent-text {
  font-size: 0.78rem;
  line-height: 1.4;
  color: var(--text-muted);
}

.auth-consent-text a {
  color: var(--ink);
  font-weight: 600;
}

.auth-primary-btn,
.auth-google-btn {
  width: 100%;
  min-height: 42px;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
}

.auth-primary-btn {
  border: none;
  background: var(--ink);
  color: var(--card);
}

.auth-primary-btn--outline {
  background: var(--card);
  color: var(--ink);
  border: 1px solid var(--border);
}

.auth-google-btn {
  border: 1px solid var(--border);
  background: var(--card);
  color: var(--ink);
}

.auth-account-label {
  margin: 0;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.auth-account-email {
  margin: 0 0 8px;
  font-weight: 600;
  word-break: break-all;
}

.auth-link-btn {
  border: none;
  background: none;
  padding: 0;
  color: var(--text-muted);
  font-size: 0.82rem;
  font-weight: 600;
  text-decoration: underline;
  cursor: pointer;
  align-self: flex-start;
}

.auth-link-btn:hover { color: var(--ink); }

.auth-verify-status {
  margin: 0 0 6px;
  font-size: 0.82rem;
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.auth-verify-badge {
  display: inline-flex;
  align-items: center;
  padding: 2px 8px;
  border-radius: 999px;
  font-size: 0.72rem;
  font-weight: 700;
}

.auth-verify-badge--ok {
  background: color-mix(in srgb, #027a48 15%, white);
  color: #027a48;
}

.auth-verify-badge--pending {
  background: color-mix(in srgb, #b42318 12%, white);
  color: #b42318;
}

.auth-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding-top: 10px;
  border-top: 1px solid var(--border);
}

.auth-section--flat {
  padding-top: 0;
  border-top: none;
}

.auth-settings-field {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.auth-settings-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  width: 100%;
  min-height: 44px;
  padding: 0 12px;
  border: 1px solid var(--border);
  border-radius: 10px;
  background: var(--card);
  color: var(--ink);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  text-align: left;
}

.auth-settings-row:hover { box-shadow: var(--shadow); }

.auth-settings-row-chevron {
  color: var(--text-muted);
  font-size: 1.1rem;
  line-height: 1;
}

.auth-panel-back {
  align-self: flex-start;
  border: none;
  background: none;
  padding: 0;
  margin: 0 0 4px;
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  cursor: pointer;
}

.auth-panel-back:hover { color: var(--ink); }

.auth-settings-legal {
  margin-top: 4px;
  padding-top: 12px;
  border-top: 1px solid var(--border);
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 4px;
  text-align: center;
  font-size: 0.78rem;
  color: var(--text-muted);
}

.auth-settings-legal a,
.auth-settings-legal .cc-reopen-link {
  color: var(--text-muted);
}

.auth-danger-zone {
  margin-top: 4px;
}

.auth-danger-text {
  margin: 0;
  font-size: 0.78rem;
  color: var(--text-muted);
  line-height: 1.4;
}

.auth-danger-btn {
  width: 100%;
  min-height: 42px;
  border-radius: 10px;
  font-weight: 600;
  cursor: pointer;
  border: 1px solid #b42318;
  background: var(--card);
  color: #b42318;
}

.auth-danger-btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.auth-delete-confirm {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 6px;
}

.auth-delete-confirm[hidden] { display: none; }

/* Mobile chrome — 仅窄屏；桌面布局不变 */
@media (max-width: 600px) {
  /* Verb quiz：进入 Vol / 收藏 / 错题 后隐藏全局顶栏（文件夹列表保留） */
  body:has(#page-quiz.is-active #quiz-tenses-view:not([hidden])) .top-nav,
  body:has(#page-quiz.is-active #quiz-session-view:not([hidden])) .top-nav {
    display: none;
  }

  /* Scenario：场景卡片列表保留顶栏返回，隐藏页内重复返回 */
  body:has(#page-scenario.is-active #scenario-scenes-view:not([hidden])) #scenario-scenes-back {
    display: none;
  }

  body:has(#page-scenario.is-active #scenario-scenes-view:not([hidden]))
    .scenario-scenes-toolbar:has(#scenario-a2-mode-btn[hidden]) {
    display: none;
    margin: 0;
    min-height: 0;
  }
}

/* Verb conjugation：手机横屏看矩阵时收起顶栏 */
@media (max-width: 900px) and (orientation: landscape) {
  body:has(#page-verbs.is-active #verb-expand:not([hidden])) .top-nav {
    display: none;
  }
}

/* 手机端：卡片横滑（quiz 单词卡 / scenario 随机卡）的 transform 溢出
   会让整页横向晃动。窄屏钳掉页面级横向溢出；桌面（≥769px）不受影响，
   保留有意的视觉溢出滑动效果。用 clip 而非 hidden：clip 不会把
   overflow-y 计算成 auto，从而不破坏 .top-nav 的 sticky 定位。 */
@media (max-width: 768px) {
  html,
  body {
    overflow-x: hidden;
    overflow-x: clip;
  }
}