html, body {
  height: 100%; margin: 0; padding: 0;
}
body {
  background: #e5ddd5;
  font-family: 'Segoe UI', 'Arial', sans-serif;
  margin: 0;
  width: 100%;
  min-height: 100dvh;
  height: 100%;
  overflow: hidden;
  display: flex;
  justify-content: center;
  align-items: stretch;
}
.overlay {
  position: fixed;
  z-index: 8888;
  top: 0; left: 0; right: 0; bottom: 0;
  background: rgba(50,40,90,0.62); /* 半透明深色 */
  display: flex;
  align-items: center;
  justify-content: center;
  transition: opacity .3s;
}
.overlay-content {
  background: #fff;
  padding: 2.2em 1.5em 2em 1.5em;
  border-radius: 17px;
  box-shadow: 0 7px 32px #4a3e5d33;
  text-align: left;
  max-width: 350px;
  width: 92vw;
  font-family: 'Noto Sans TC', Arial, sans-serif;
}

.start-btn {
  margin-top: 1.5em;
  font-size: 1.13em;
  background: linear-gradient(90deg,#6e49ff 70%,#ba81e3 100%);
  color: #fff;
  border: none;
  border-radius: 25px;
  padding: 0.6em 2.5em;
  font-weight: 700;
  cursor: pointer;
  box-shadow: 0 3px 12px #a991ff29;
  letter-spacing: 1px;
  transition: background .18s, transform .14s;
}
.start-btn:hover { background: #7c63d3; transform: scale(1.03);}

.leave-btn {
  position: fixed;
  left: 16px;
  bottom: 18px;
  z-index: 999;
  background: #651fff;
  color: #fff;
  font-size: 0.75em;
  font-family: inherit;
  border: none;
  border-radius: 999px;
  box-shadow: 0 2px 18px #baaefb50;
  padding: 0.66em 1.45em;
  font-weight: 700;
  cursor: pointer;
  opacity: 0.97;
  transition: background 0.18s, box-shadow 0.15s, transform 0.13s;
}
.leave-btn:hover {
  background: linear-gradient(90deg, #5122c9 60%, #a21caf 100%);
  box-shadow: 0 6px 20px #baaefb80;
  transform: scale(0.98);
}
.chat-container {
  background: #ece5dd;
  width: 100%;
  height: 100%;
  max-width: 500px;
  min-width: 0;
  min-height: 0;
  margin: 0;
  border-radius: 0;
  box-shadow: 0 4px 0px #bbb6;
  display: flex;
  flex-direction: column;
  padding-bottom: 0;
  overflow: hidden;
  position: fixed;
}
.chat-header {
  flex-shrink: 0;
  background: #075e54;
  color: #fff;
  padding: 18px;
  font-size: 1.15em;
  font-weight: bold;
  text-align: left;
  letter-spacing: 1px;
  border-radius: 18px 18px 0 0;
  padding-right: 74px;
}
.main-menu-btn {
  position: absolute;
  right: 14px;
  top: 18px;
  background: #0ba26e;
  color: #fff;
  border: none;
  border-radius: 6px;
  padding: 3px 8px;
  font-size: 0.8em;
  font-weight: 500;
  cursor: pointer;
}
.chat-box {
  flex: 1 1 auto;
  padding: 22px 14px 0 14px;
  min-height: 0;
  max-height: 85vh;
  box-sizing: border-box;
  background: #ece5dd;
  display: flex;
  flex-direction: column;
  gap: 0;
  overflow-y: auto;
  scroll-behavior: auto;
  position: relative;
}
.chat-msg { display: flex; flex-direction: column; max-width: 82%; word-break: break-word; margin-bottom: 28px; position: relative; }
.chat-msg.a { align-self: flex-start; align-items: flex-start; }
.chat-msg.b { align-self: flex-end; align-items: flex-end; }
.bubble {
  padding: 11px 38px 11px 15px;
  border-radius: 18px;
  font-size: 1.06em;
  margin-bottom: 7px;
  line-height: 1.44;
  box-shadow: 0 1px 4px #aaa2;
  background: #fff;
  position: relative;
  min-width: 72px;
}
.chat-msg.b .bubble { background: #dcf8c6; color: #222; border-bottom-right-radius: 5px; }
.chat-msg.a .bubble { background: #fff; color: #222; border-bottom-left-radius: 5px; }
.speaker-icon {
  position: absolute;
  right: 12px; bottom: 13px; width: 22px; height: 22px; cursor: pointer; opacity: 0.75; transition: opacity 0.2s; z-index: 2;
  background: none; border: none; padding: 0; display: flex; align-items: center; justify-content: center;
}
.speaker-icon:hover, .speaker-icon:active { opacity: 1; }
.speaker-icon .spinner { display: none; }
.speaker-icon.loading svg.speaker-svg { display: none; }
.speaker-icon.loading .spinner {
  display: block; width: 20px; height: 20px; margin: 0 auto;
  border: 2.5px solid #ccc; border-top: 2.5px solid #45966c;
  border-radius: 50%; animation: spin 0.7s linear infinite; background: none;
}
@keyframes spin { 0% { transform: rotate(0);} 100% { transform: rotate(360deg);} }
.translation {
  font-size: 0.97em;
  color: #757575;
  padding-top: 1px;
  padding-left: 2px;
  margin-bottom: 0;
  display: none;
}
.tap-hint {
  background: none;
  color: #b0afaf;
  font-size: 1em;
  text-align: center;
  margin: 0;
  padding: 8px 0 8px 0;
  user-select: none;
  box-shadow: none;
  border: none;
  pointer-events: none;
  transition: color 0.3s;
}
.vocab-review {
  padding: 20px 20px 30px 20px;
  background: #f8fff7;
  font-size: 1.03em;
  height: 98%;
  overflow-y: auto;
  box-sizing: border-box;
  display: none;
  flex-direction: column;
}
.vocab-head { margin-bottom: 2px; }
.vocab-head-row { display: flex; align-items: center; gap: 7px; }
.vocab-en { font-weight: bold; font-size: 1.17em; color: #0d6544; margin-right: 0; }
.vocab-speaker { cursor: pointer; opacity: 0.7; border: none; background: none; padding: 0; width: 20px; height: 20px; display: inline-flex; align-items: center; margin-left: 2px; margin-bottom: 0; vertical-align: middle;}
.vocab-speaker:hover { opacity: 1; }
.vocab-zh { color: #555; margin-left: 0; display: inline-block; font-size: 0.8em; }
.vocab-example { margin-top: 4px; margin-left: 0; color: #333; font-style: italic; font-size: 1em;}
.vocab-example-zh { margin-left: 0; color: #666; font-size: 0.8em; display: block; margin-bottom: 3px;}
.vocab-item { margin-bottom: 21px; border-bottom: 1px dashed #aadac2; padding-bottom: 10px;}


/* ------- Toggle Switch 優化 ------- */
.toggle-switch {
  display: inline-flex;
  align-items: center;
  margin-left: 9px;
  font-size: 0.97em;
  vertical-align: middle;
  user-select: none;
  cursor: pointer;
}
.toggle-switch input[type="checkbox"] {
  display: none;
}
.toggle-slider {
  width: 40px;   /* 讓“翻譯”完全顯示並有點寬度緩衝 */
  height: 20px;
  background: #ccc;
  border-radius: 20px;
  position: relative;
  transition: background 0.2s;
  box-sizing: border-box;
  display: flex;
  align-items: center;
  justify-content: center;
}
.toggle-slider .toggle-label {
  position: absolute;
  right: 5px;  /* 與右邊留空距離，可依需求微調 */
  top: 50%;
  transform: translateY(-50%);
  font-size: 13px;
  color: #555;
  font-weight: 500;
  letter-spacing: 1px;
  pointer-events: none;
  z-index: 1;
  background: transparent;
}
.toggle-slider:after {
  content: '';
  position: absolute;
  width: 14px;
  height: 14px;
  left: 3px;
  top: 3px;
  border-radius: 50%;
  background: #fff;
  transition: transform 0.2s;
  box-shadow: 0 1px 2px #0002;
  z-index: 2;
}
.toggle-switch input[type="checkbox"]:checked + .toggle-slider {
  background: #0ba26e;
}
.toggle-switch input[type="checkbox"]:checked + .toggle-slider .toggle-label {
  opacity: 0;
}
.toggle-switch input[type="checkbox"]:checked + .toggle-slider:after {
  transform: translateX(18px);
}

@media (max-width: 500px) {
  .leave-btn {
    font-size: 0.85em;
    left: 7px;
    bottom: 9px;
    padding: 0.57em 1.09em;
  }
  .chat-container { width: 100%; border-radius: 0; }
  .chat-header { border-radius: 0; }
  .chat-box { max-height: 85vh; min-height: 260px; }
  .vocab-review { padding: 13px 6vw 20px 6vw; height: 98%; }
  .toggle-slider { width: 38px; height: 20px; }
  .toggle-slider .toggle-label { font-size: 11px;}
  .toggle-slider:after { width: 13px; height: 13px; top: 3px; left: 4px;}
}