:root {
  --chat-vvh: 100vh;
  --color-bg: #eaf1f8;
  --color-bg-soft: #f5f9fd;
  --color-surface: #ffffff;
  --color-text: #16263a;
  --color-text-soft: #5b6d80;
  --color-border: #c8d4e1;
  --color-accent: #0f6fd1;
  --color-accent-strong: #0c5cad;
  --color-success: #1d7f3d;
  --color-danger: #b3261e;
  --color-danger-strong: #8d1f19;
  --radius-sm: .55rem;
  --radius-md: .8rem;
  --radius-lg: 1rem;
  --focus-ring: 0 0 0 3px rgba(15, 111, 209, .28);
  --shadow-card: 0 10px 30px rgba(16, 36, 58, .12);
  --shadow-soft: 0 2px 10px rgba(16, 36, 58, .08);
}
html, body { height: 100%; }
body {
  font-family: "Segoe UI", "Avenir Next", "Helvetica Neue", Arial, sans-serif;
  margin: 0;
  overflow: hidden;
  background: radial-gradient(circle at 20% -15%, #f9fcff 0%, var(--color-bg) 52%, #dde9f5 100%);
  color: var(--color-text);
  line-height: 1.45;
}
.container {
  max-width: 920px;
  width: 100%;
  height: var(--chat-vvh);
  min-height: 320px;
  margin: 0 auto;
  padding: .8rem;
  box-sizing: border-box;
  display: flex;
  flex-direction: column;
  min-height: 0;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}
form#chatForm {
  flex: 1 1 auto;
  min-height: 0;
  display: flex;
  flex-direction: column;
  overflow: hidden;
}
#chat {
  flex: 1 1 auto;
  min-height: 0;
  overflow: auto;
  white-space: pre-wrap;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: .65rem .7rem;
  background: var(--color-bg-soft);
  -webkit-overflow-scrolling: touch;
  overscroll-behavior: contain;
}
.lockbanner {
  background: var(--color-danger);
  color: #fff;
  padding: .6rem .8rem;
  border-radius: var(--radius-md);
  margin-bottom: .55rem;
  box-shadow: var(--shadow-soft);
}
.lockbanner[hidden] { display:none; }

.ui-mode-prompt {
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:.55rem;
  margin: .1rem 0 .55rem;
  padding: .55rem .65rem;
  border: 1px solid #bfd0e2;
  border-radius: var(--radius-md);
  background: #f0f6fc;
}
.ui-mode-prompt[hidden] { display:none; }
.ui-mode-prompt-label {
  font-size: .93rem;
  color: var(--color-text-soft);
}
.ui-mode-actions {
  display:flex;
  align-items:center;
  gap:.4rem;
}
.ui-mode-btn {
  min-height: 40px;
  padding: .4rem .75rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-surface);
  color: var(--color-text);
  font: inherit;
}
.ui-mode-btn:hover { background: #edf4fb; }
.ui-mode-btn:focus-visible {
  outline: none;
  border-color: var(--color-accent);
  box-shadow: var(--focus-ring);
}

.controls {
  display:flex;
  gap:.5rem;
  align-items:flex-end;
  flex-wrap: wrap;
  margin: .3rem 0 .6rem;
}
.mobile-ui-control {
  display:inline-flex;
}
.mobile-ui-control[hidden] {
  display:none;
}
.toggle {
  display:inline-flex;
  align-items:center;
  gap:.5rem;
  padding:.5rem .72rem;
  border-radius: var(--radius-md);
  border:1px solid var(--color-border);
  background: var(--color-surface);
  transition:border-color .15s ease, box-shadow .15s ease, background .15s ease;
  font:inherit;
  color: var(--color-text);
  text-align:left;
}
.toggle {
  appearance:none;
  user-select:none;
}
.toggle:hover { background:#f3f8fd; }
.toggle:focus-visible,
#name:focus-visible,
#message:focus-visible,
button:focus-visible,
input[type="submit"]:focus-visible {
  outline:none;
  border-color: var(--color-accent);
  box-shadow: var(--focus-ring);
}
.toggle[role="switch"][aria-checked="true"] { border-color: var(--color-accent); }
.toggle-label { line-height:1.2; }
.toggle-switch {
  position:relative;
  width:2.25rem;
  height:1.25rem;
  border-radius:999px;
  background:#aebdcc;
  flex:0 0 auto;
  transition:background .2s ease;
}
.toggle-thumb {
  position:absolute;
  top:2px;
  left:2px;
  width:.85rem;
  height:.85rem;
  border-radius:50%;
  background:#fff;
  box-shadow:0 1px 2px rgba(0,0,0,.22);
  transition:transform .2s ease;
}
.toggle[role="switch"][aria-checked="true"] .toggle-switch { background: var(--color-accent); }
.toggle[role="switch"][aria-checked="true"] .toggle-thumb { transform:translateX(1rem); }
.toggle strong { white-space:nowrap; min-width:3.8rem; text-align:right; }
button:disabled,
input[type="submit"]:disabled {
  opacity:.6;
  cursor:not-allowed;
}

#status {
  color: var(--color-text-soft);
  font-size: .93rem;
}
.offscreen {
  position:absolute;
  left:-9999px;
  width:1px;
  height:1px;
  overflow:hidden;
}
.msg {
  padding: .32rem 0;
  color: var(--color-text);
}
.time { color: var(--color-text-soft); }
.name {
  font-weight: 700;
  color: #21384f;
  overflow-wrap: anywhere;
}
.msg .text {
  overflow-wrap: anywhere;
}
button, input[type="submit"] {
  cursor:pointer;
  min-height: 44px;
  touch-action: manipulation;
}
label {
  display:block;
  margin-top:.5rem;
  color: #334b65;
}
#placeholderMsg {
  color: var(--color-text-soft);
  font-style:italic;
}
.name-field {
  display:flex;
  flex-direction:column;
  flex: 1 1 14rem;
  min-width: 13rem;
}
.name-field label { margin:0 0 .25rem 0; }
#name, #message {
  width: 100%;
  max-width: 100%;
  box-sizing: border-box;
  min-height: 44px;
  padding: .58rem .66rem;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-size: 16px;
  color: var(--color-text);
  background: #fff;
}
.message-row {
  display:flex;
  gap:.5rem;
  align-items:center;
}
.message-row #message { flex:1 1 auto; }
.message-row input[type="submit"] {
  flex: 0 0 auto;
  padding: .58rem 1rem;
  border: 1px solid var(--color-accent-strong);
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  font-weight: 600;
}
.message-row input[type="submit"]:hover { background: var(--color-accent-strong); }
.composer {
  margin-top: .6rem;
  padding: .55rem .1rem max(.45rem, env(safe-area-inset-bottom));
  border-top: 1px solid #d8e2ec;
  background: var(--color-surface);
}
.voice-row {
  display:flex;
  gap:.5rem;
  align-items:center;
  margin-top:.55rem;
  flex-wrap:wrap;
}
#voiceBtn {
  padding: .58rem .98rem;
  border: 1px solid var(--color-accent-strong);
  border-radius: var(--radius-sm);
  background: #eef5fd;
  color: #173651;
}
#voiceBtn:hover { background:#e2eefb; }
#voiceBtn.recording {
  background: var(--color-danger);
  border-color: var(--color-danger-strong);
  color:#fff;
}
#voiceStatus {
  color: var(--color-text-soft);
}
#voiceTimer {
  color: var(--color-text-soft);
  min-width:6.8rem;
  font-variant-numeric: tabular-nums;
}
.msg.voice .voice-play-btn {
  margin-top:.2rem;
  min-height: 36px;
  padding:.34rem .72rem;
  border:1px solid var(--color-border);
  border-radius: var(--radius-sm);
  background:#f2f7fc;
  color:#1f3a53;
}
.msg.voice .voice-play-btn:hover { background:#e8f0f9; }
.msg.voice .voice-play-btn:focus-visible {
  outline:none;
  border-color: var(--color-accent);
  box-shadow: var(--focus-ring);
}

.is-mobile-ui .container {
  padding: .65rem;
}
.is-mobile-ui .ui-mode-prompt {
  flex-direction: column;
  align-items: stretch;
}
.is-mobile-ui .ui-mode-actions {
  width: 100%;
}
.is-mobile-ui .ui-mode-btn {
  flex: 1 1 auto;
}
.is-mobile-ui .controls {
  align-items:stretch;
  gap:.4rem;
  margin: .25rem 0 .5rem;
}
.is-mobile-ui .toggle {
  width: 100%;
  justify-content:space-between;
  text-align:left;
}
.is-mobile-ui .mobile-ui-control {
  width:100%;
}
.is-mobile-ui .mobile-ui-control .toggle {
  width:100%;
  justify-content:space-between;
  text-align:left;
}
.is-mobile-ui .name-field {
  min-width: 100%;
  flex-basis: 100%;
}
.is-mobile-ui .composer {
  margin-top: .5rem;
  padding-top: .6rem;
}
.is-mobile-ui .message-row {
  flex-direction:column;
  align-items:stretch;
}
.is-mobile-ui .message-row input[type="submit"] {
  width: 100%;
  min-height: 46px;
}
.is-mobile-ui .voice-row {
  align-items:stretch;
}
.is-mobile-ui #voiceBtn {
  width: 100%;
  min-height: 46px;
}

@media (max-width: 760px) {
  .container {
    border-radius: 0;
    border-left: 0;
    border-right: 0;
    box-shadow: none;
  }
}