/* ===== 一体化暖纸时间线布局 ===== */

.app {
  display: grid;
  grid-template-rows: auto 1fr;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

.sidebar {
  background: var(--paper-2);
  border-bottom: 1px solid var(--line);
  display: flex;
  flex-direction: column;
  min-height: 0;
}

.sidebar-head {
  padding: 16px 18px 12px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 14px;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: 'Fraunces', serif;
  font-weight: 600;
  font-size: 17px;
  letter-spacing: 0;
}

.brand-mark {
  width: 30px;
  height: 30px;
  border-radius: 9px;
  background: var(--clay);
  color: var(--clay-ink);
  display: grid;
  place-items: center;
  font-size: 16px;
  transition: transform .5s var(--spring);
}

.brand-mark:hover { transform: rotate(-8deg) scale(1.05); }

.brand-sub {
  font-family: 'Inter', sans-serif;
  font-size: 10.5px;
  color: var(--ink-3);
  font-weight: 400;
  letter-spacing: 0.02em;
}

.top-actions {
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.new-chat-btn {
  padding: 10px 13px;
  border-radius: var(--r-sm);
  border: 1px dashed var(--line-2);
  background: var(--card);
  color: var(--ink-2);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: all .35s var(--ease);
}

.new-chat-btn:hover {
  border-color: var(--clay);
  border-style: solid;
  color: var(--clay-deep);
  background: var(--clay-soft);
  transform: translateY(-1px);
}

.new-chat-btn svg { width: 15px; height: 15px; }

.theme-toggle {
  display: flex;
  gap: 3px;
  background: var(--card-2);
  border-radius: 999px;
  padding: 3px;
}

.theme-toggle button {
  border: none;
  background: transparent;
  width: 26px;
  height: 26px;
  border-radius: 999px;
  cursor: pointer;
  color: var(--ink-3);
  display: grid;
  place-items: center;
  transition: all .35s var(--spring);
}

.theme-toggle button.on {
  background: var(--card);
  color: var(--clay-deep);
  box-shadow: var(--shadow-sm);
}

.theme-toggle button svg { width: 13px; height: 13px; }

.session-list {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  padding: 0 18px 14px;
  min-height: 0;
}

.session-item {
  min-width: 190px;
  max-width: 260px;
  padding: 10px 12px;
  border-radius: var(--r-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 9px;
  position: relative;
  transition: background .25s var(--ease);
  animation: fadeInUp .4s var(--ease) both;
  background: rgba(251, 249, 245, 0.75);
  border: 1px solid transparent;
}

.session-item:hover { background: var(--card-2); }
.session-item.active { background: var(--clay-soft); border-color: var(--clay-line); }

.session-item .dot {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  background: var(--ink-4);
  flex-shrink: 0;
  transition: background .3s var(--ease);
}

.session-item.active .dot { background: var(--clay); }

.session-item .title {
  flex: 1;
  font-size: 13px;
  color: var(--ink-2);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.session-item.active .title { color: var(--ink); font-weight: 500; }

.session-item .meta-mini {
  font-size: 10px;
  color: var(--ink-4);
  font-variant-numeric: tabular-nums;
}

.session-item .del {
  opacity: 0;
  width: 22px;
  height: 22px;
  border-radius: 6px;
  display: grid;
  place-items: center;
  color: var(--ink-3);
  transition: all .25s var(--ease);
}

.session-item:hover .del { opacity: 1; }
.session-item .del:hover { background: var(--err); color: #fff; }
.session-item .del svg { width: 12px; height: 12px; }

.main {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;
  background: var(--paper);
  position: relative;
}

.main-head {
  padding: 16px 28px;
  border-bottom: 1px solid var(--line);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  background: color-mix(in srgb, var(--paper) 85%, transparent);
  backdrop-filter: blur(16px) saturate(1.4);
  -webkit-backdrop-filter: blur(16px) saturate(1.4);
}

.main-head .title-wrap { min-width: 0; }

.main-head .session-title {
  font-family: 'Fraunces', serif;
  font-size: 18px;
  font-weight: 600;
  letter-spacing: 0;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.main-head .session-sub {
  font-size: 11px;
  color: var(--ink-3);
  margin-top: 1px;
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
}

.session-sub .tag {
  display: inline-flex;
  align-items: center;
  gap: 4px;
}

.session-sub .tag .pill {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--ok);
}

.session-sub .tag.thinking .pill { background: var(--clay); }

.chat-scroll {
  flex: 1;
  overflow-y: auto;
  scroll-behavior: smooth;
  padding: 28px 0 8px;
}

.chat-inner {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 28px 26px;
}

.empty-state {
  text-align: center;
  padding: 80px 20px;
  animation: fadeInUp .6s var(--ease) both;
}

.empty-icon {
  width: 76px;
  height: 76px;
  margin: 0 auto 22px;
  border-radius: 22px;
  background: var(--card);
  border: 1px solid var(--line);
  display: grid;
  place-items: center;
  color: var(--clay);
  box-shadow: var(--shadow);
  animation: floaty 4.5s var(--ease-soft) infinite;
}

.empty-icon svg { width: 34px; height: 34px; }

.empty-state h2 {
  font-family: 'Fraunces', serif;
  font-size: 26px;
  font-weight: 600;
  letter-spacing: 0;
  margin-bottom: 10px;
}

.empty-state h2 em {
  font-style: italic;
  color: var(--clay-deep);
}

.empty-state p {
  color: var(--ink-3);
  font-size: 14px;
  max-width: 520px;
  margin: 0 auto;
  line-height: 1.7;
}

.empty-hints {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
  margin-top: 26px;
}

.empty-hints .hint {
  padding: 7px 13px;
  border-radius: 999px;
  border: 1px solid var(--line);
  background: var(--card);
  color: var(--ink-2);
  font-size: 12px;
  cursor: pointer;
  transition: all .3s var(--ease);
}

.empty-hints .hint:hover {
  border-color: var(--clay);
  color: var(--clay-deep);
  background: var(--clay-soft);
  transform: translateY(-1px);
}

.timeline-node {
  position: relative;
  display: grid;
  grid-template-columns: 76px minmax(0, 1fr);
  gap: 14px;
  padding: 18px 0 24px;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 72%, transparent);
  z-index: 1;
}

.timeline-node:hover,
.timeline-node.is-selected,
.timeline-node.is-editing {
  z-index: 30;
}

.timeline-node.streaming {
  z-index: 22;
}

.timeline-node::before {
  content: '';
  position: absolute;
  left: 28px;
  top: 28px;
  bottom: -1px;
  width: 1px;
  background: linear-gradient(var(--line), transparent);
}

.timeline-node.user::before { background: linear-gradient(var(--line), rgba(105,123,97,.18)); }

.timeline-role {
  color: var(--ink-3);
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .1em;
  padding-top: 1px;
  padding-left: 2px;
}

.timeline-body {
  min-width: 0;
  position: relative;
}

.editable-text {
  margin: 0;
  font-size: 17px;
  line-height: 1.78;
  outline: none;
  border-radius: 3px;
  max-width: none;
  width: 100%;
}

.editable-text[contenteditable="true"] {
  background: linear-gradient(180deg, transparent 58%, rgba(201, 109, 74, 0.13) 58%);
  box-shadow: 0 2px 0 rgba(201, 109, 74, 0.22);
  caret-color: var(--clay);
}

.reasoning {
  margin: 0 0 14px 0;
  padding: 0 0 0 14px;
  border-left: 2px solid var(--clay);
  color: var(--ink-2);
  font-size: 14px;
  max-width: none;
  width: 100%;
}

.reasoning summary,
.reasoning-head {
  color: var(--clay-deep);
  cursor: pointer;
  font-size: 12px;
  text-transform: uppercase;
  letter-spacing: .08em;
  margin-bottom: 8px;
  list-style: none;
}

.reasoning-body {
  white-space: pre-wrap;
  line-height: 1.7;
}

.reasoning.collapsed .reasoning-body {
  display: none;
}

.node-tools {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-top: 12px;
  flex-wrap: wrap;
}

.edit-hint {
  color: var(--ink-3);
  font-size: 11px;
  opacity: .65;
}

.branch-wrap {
  position: relative;
  display: inline-flex;
  z-index: 1;
}

.branch-chip {
  border: 1px solid var(--clay-line);
  background: var(--clay-soft);
  color: var(--clay-deep);
  border-radius: 999px;
  padding: 5px 10px;
  font-size: 12px;
}

.branch-menu {
  position: absolute;
  top: calc(100% + 8px);
  left: 0;
  z-index: 120;
  min-width: 188px;
  display: none;
  padding: 6px;
  border: 1px solid var(--line-2);
  border-radius: var(--radius);
  background: #fbf8f2;
  box-shadow: 0 14px 34px rgba(62, 50, 37, 0.12);
}

.branch-wrap.open .branch-menu {
  display: grid;
  gap: 3px;
}

.branch-wrap.open {
  z-index: 140;
}

.branch-menu button {
  width: 100%;
  text-align: left;
  border-color: transparent;
  background: transparent;
  font-size: 12px;
}

.branch-menu button:hover {
  background: var(--clay-soft);
}

.branch-switch {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  font-size: 11px;
  color: var(--ink-3);
  background: var(--card-2);
  border-radius: 999px;
  padding: 2px 4px;
  margin-top: 7px;
}

.timeline-node.is-selected .timeline-body,
.timeline-node.is-editing .timeline-body {
  z-index: 40;
}

.branch-switch button {
  border: none;
  background: transparent;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  cursor: pointer;
  color: var(--ink-3);
  display: grid;
  place-items: center;
  transition: all .25s var(--ease);
}

.branch-switch button:hover {
  background: var(--clay-soft);
  color: var(--clay-deep);
}

.branch-switch .pos {
  font-variant-numeric: tabular-nums;
  padding: 0 4px;
  min-width: 28px;
  text-align: center;
}

.prefix-zone {
  margin: 8px 0 24px;
  padding-left: 76px;
}

.prefix-card {
  position: relative;
  padding: 18px 0 0;
  border-top: 2px solid var(--ink);
}

.prefix-card::before {
  content: '';
  position: absolute;
  left: -14px;
  top: -7px;
  width: 10px;
  height: 10px;
  border-radius: 50%;
  background: var(--clay);
  box-shadow: 0 0 0 6px var(--paper);
}

.prefix-label {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 12px;
  color: var(--clay-deep);
  font-weight: 600;
  margin-bottom: 4px;
}

.prefix-label .pulse {
  width: 8px;
  height: 8px;
  border-radius: 50%;
  background: var(--clay);
  animation: pulse 1.8s var(--ease-soft) infinite;
}

.prefix-hint {
  font-size: 12px;
  color: var(--ink-3);
  margin-bottom: 12px;
  line-height: 1.6;
  max-width: 780px;
}

.prefix-textarea {
  width: 100%;
  min-height: 110px;
  resize: vertical;
  border: 1px solid var(--line);
  border-radius: var(--r-sm);
  background: var(--card);
  color: var(--ink);
  padding: 11px 13px;
  font-family: inherit;
  font-size: 13px;
  line-height: 1.7;
  outline: none;
  transition: border-color .3s var(--ease), box-shadow .3s var(--ease);
}

.prefix-textarea:focus {
  border-color: var(--clay);
  box-shadow: 0 0 0 3px var(--clay-soft);
}

.prefix-textarea::placeholder { color: var(--ink-4); }

.prefix-actions {
  display: flex;
  gap: 9px;
  margin-top: 13px;
  justify-content: flex-end;
  align-items: center;
}

.prefix-spacer {
  flex: 1;
  font-size: 11px;
  color: var(--ink-4);
}

.composer {
  border-top: none;
  padding: 10px 0 22px;
  background: transparent;
}

.composer-inner {
  max-width: 1000px;
  margin: 0 auto;
  padding: 0 28px;
  position: relative;
}

.composer-inner::before {
  content: '';
  position: absolute;
  left: 28px;
  top: -10px;
  bottom: 22px;
  width: 1px;
  background: linear-gradient(var(--line), transparent);
}

.next-headline {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: baseline;
  margin: 0 0 10px 76px;
}

.next-kicker {
  font-family: 'Fraunces', serif;
  font-size: 15px;
  font-weight: 600;
  letter-spacing: 0;
}

.next-note {
  color: var(--ink-3);
  font-size: 11.5px;
}

.composer-box {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  background: transparent;
  border-bottom: 1px solid var(--line-2);
  padding: 10px 0 12px;
  transition: border-color .3s var(--ease), box-shadow .3s var(--ease);
  margin-left: 76px;
}

.composer-box:focus-within {
  border-color: var(--clay);
  box-shadow: 0 0 0 3px var(--clay-soft);
}

.composer textarea {
  flex: 1;
  border: none;
  background: transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: 14.5px;
  line-height: 1.6;
  resize: none;
  outline: none;
  max-height: 160px;
  padding: 4px 0;
}

.composer textarea::placeholder { color: var(--ink-4); }

.send-btn {
  width: 38px;
  height: 38px;
  border-radius: 11px;
  border: 1px solid var(--clay);
  background: var(--clay);
  color: var(--clay-ink);
  cursor: pointer;
  display: grid;
  place-items: center;
  flex-shrink: 0;
  transition: all .35s var(--spring);
  box-shadow: var(--shadow-sm);
}

.send-btn:hover {
  transform: translateY(-1px) scale(1.04);
  box-shadow: var(--shadow);
}

.send-btn:active { transform: scale(0.96); }
.send-btn:disabled { background: var(--ink-4); cursor: not-allowed; transform: none; box-shadow: none; }
.send-btn svg { width: 17px; height: 17px; }

.composer-hint {
  text-align: right;
  font-size: 11px;
  color: var(--ink-4);
  margin-top: 8px;
}

.params {
  margin-top: 14px;
  display: grid;
  gap: 12px;
  margin-left: 76px;
}

.param-group {
  margin-bottom: 0;
  animation: fadeInUp .4s var(--ease) both;
}

.param-label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 12px;
  font-weight: 600;
  color: var(--ink-2);
  margin-bottom: 7px;
}

.param-label .val {
  font-family: 'Inter', monospace;
  font-variant-numeric: tabular-nums;
  font-weight: 500;
  color: var(--clay-deep);
  background: var(--clay-soft);
  padding: 1px 7px;
  border-radius: 999px;
  font-size: 11px;
}

.param-input,
.param-select,
.param-textarea {
  width: 100%;
  padding: 8px 11px;
  border: 1px solid var(--line-2);
  border-radius: var(--r-xs);
  background: var(--card);
  color: var(--ink);
  font-family: inherit;
  font-size: 13px;
  outline: none;
  transition: border-color .3s var(--ease), box-shadow .3s var(--ease);
}

.param-input:focus,
.param-select:focus,
.param-textarea:focus {
  border-color: var(--clay);
  box-shadow: 0 0 0 3px var(--clay-soft);
}

.param-textarea {
  min-height: 70px;
  resize: vertical;
  font-size: 12.5px;
  line-height: 1.6;
}

.slider-row {
  display: flex;
  align-items: center;
  gap: 10px;
}

input[type="range"] {
  -webkit-appearance: none;
  appearance: none;
  flex: 1;
  height: 4px;
  border-radius: 999px;
  background: var(--line-2);
  outline: none;
  cursor: pointer;
}

input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 16px;
  height: 16px;
  border-radius: 50%;
  background: var(--clay);
  border: 2px solid var(--card);
  box-shadow: var(--shadow-sm);
  cursor: pointer;
  transition: transform .25s var(--spring);
}

input[type="range"]::-webkit-slider-thumb:hover { transform: scale(1.2); }

input[type="range"]::-moz-range-thumb {
  width: 14px;
  height: 14px;
  border-radius: 50%;
  background: var(--clay);
  border: 2px solid var(--card);
  cursor: pointer;
}

.seg {
  display: flex;
  gap: 3px;
  background: var(--card-2);
  border-radius: var(--r-xs);
  padding: 3px;
}

.seg button {
  flex: 1;
  border: none;
  background: transparent;
  padding: 6px 10px;
  border-radius: 6px;
  font-size: 12px;
  color: var(--ink-3);
  cursor: pointer;
  font-family: inherit;
  transition: all .3s var(--spring);
}

.seg button.on {
  background: var(--card);
  color: var(--clay-deep);
  box-shadow: var(--shadow-sm);
}

.advanced {
  border-top: 1px solid var(--line);
  padding-top: 2px;
}

.advanced summary {
  cursor: pointer;
  color: var(--ink-3);
  font-size: 12px;
  list-style: none;
  margin-bottom: 10px;
}

.advanced summary::-webkit-details-marker { display: none; }

.advanced-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}

.toast-wrap {
  position: fixed;
  top: 18px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 8px;
  pointer-events: none;
}

.toast {
  background: var(--ink);
  color: var(--paper);
  padding: 10px 16px;
  border-radius: var(--r-sm);
  font-size: 13px;
  box-shadow: var(--shadow-lg);
  animation: toastIn .4s var(--spring) both;
  display: flex;
  align-items: center;
  gap: 8px;
  pointer-events: auto;
}

.toast.err { background: var(--err); color: #fff; }
.toast.ok { background: var(--ok); color: #fff; }
.toast.out { animation: toastOut .35s var(--ease) forwards; }

.loading-overlay {
  position: absolute;
  inset: 0;
  background: color-mix(in srgb, var(--paper) 60%, transparent);
  backdrop-filter: blur(2px);
  display: grid;
  place-items: center;
  z-index: 50;
  animation: fadeIn .3s var(--ease);
}

.loading-overlay .spinner {
  width: 38px;
  height: 38px;
  border: 3px solid var(--line-2);
  border-top-color: var(--clay);
  border-radius: 50%;
  animation: spin .8s linear infinite;
}

.msg-edit-area {
  width: 100%;
  min-height: 80px;
  padding: 11px 13px;
  border: 1px solid var(--clay);
  border-radius: var(--r-sm);
  background: var(--paper);
  color: var(--ink);
  font-family: inherit;
  font-size: 14px;
  line-height: 1.6;
  resize: vertical;
  outline: none;
  box-shadow: 0 0 0 3px var(--clay-soft);
}

.msg-edit-actions {
  display: flex;
  gap: 7px;
  margin-top: 8px;
  justify-content: flex-end;
}

.btn-mini {
  padding: 5px 12px;
  border-radius: 7px;
  border: 1px solid var(--line-2);
  background: var(--card);
  color: var(--ink-2);
  font-size: 12px;
  cursor: pointer;
  font-family: inherit;
  transition: all .25s var(--ease);
}

.btn-mini:hover { border-color: var(--ink-4); color: var(--ink); }

.btn-mini.primary {
  background: var(--clay);
  border-color: var(--clay);
  color: var(--clay-ink);
}

.btn-mini.primary:hover { background: var(--clay-deep); }

@media (max-width: 900px) {
  .app { grid-template-rows: auto 1fr; }
  .sidebar-head { padding: 14px 14px 10px; }
  .session-list { padding: 0 14px 12px; }
  .main-head { padding: 14px 16px; }
  .chat-inner { padding: 0 16px 22px; }
  .composer { padding: 10px 0 18px; }
  .timeline-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }
  .timeline-node::before { left: 6px; top: 24px; }
  .timeline-role { padding-left: 0; }
  .prefix-zone { padding-left: 0; }
  .editable-text { font-size: 16px; }
  .advanced-grid { grid-template-columns: 1fr; }
  .next-headline { flex-direction: column; align-items: flex-start; }
  .composer-hint { text-align: left; }
}


/* ===== layout-v2 overrides ===== */
.chat-scroll {
  padding: 22px 0 10px;
}

.chat-inner {
  max-width: 960px;
  padding: 0 24px 28px;
  display: flex;
  flex-direction: column;
  position: relative;
  isolation: isolate;
}

.chat-body {
  display: flex;
  flex-direction: column;
}

.timeline-node {
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 10px;
}

.timeline-node::before {
  left: 22px;
}

.timeline-role {
  padding-left: 0;
}

.prefix-zone {
  padding-left: 58px;
}

.prefix-card {
  border-top-color: color-mix(in srgb, var(--line) 86%, var(--ink) 14%);
}

.composer-node {
  position: relative;
  display: grid;
  grid-template-columns: 58px minmax(0, 1fr);
  gap: 10px;
  padding: 22px 0 28px;
  border-top: 1px solid color-mix(in srgb, var(--line) 78%, transparent);
  margin-top: 4px;
}

.composer-node::before {
  content: '';
  position: absolute;
  left: 22px;
  top: 22px;
  bottom: -1px;
  width: 1px;
  background: linear-gradient(var(--line), transparent);
}

.composer-node .timeline-role {
  padding-top: 2px;
}

.composer-node .timeline-body {
  min-width: 0;
  position: relative;
  display: flex;
  flex-direction: column;
}

.composer-node .next-headline {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  align-items: baseline;
  margin: 0 0 10px;
}

.composer-node .composer-box {
  margin-left: 0;
}

.composer-node .params {
  margin-left: 0;
}

.timeline-node.branch-open {
  z-index: 260;
}

.timeline-node.branch-open .timeline-body {
  z-index: 260;
}

.branch-wrap {
  z-index: 2;
}

.branch-menu {
  z-index: 320;
}

.branch-wrap.open {
  z-index: 340;
}

@media (max-width: 900px) {
  .chat-inner {
    max-width: none;
    padding: 0 16px 24px;
  }

  .timeline-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .timeline-node::before {
    left: 6px;
    top: 24px;
  }

  .prefix-zone {
    padding-left: 0;
  }

  .composer-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .composer-node::before {
    left: 6px;
    top: 24px;
  }

  .composer-node .next-headline {
    flex-direction: column;
    align-items: flex-start;
  }

  .composer-node .composer-hint {
    text-align: left;
  }
}


/* ===== history overflow guard ===== */
html,
body,
.app,
.main,
.chat-scroll,
.chat-inner,
.chat-body,
.timeline-node,
.timeline-body,
.composer-node {
  max-width: 100%;
  min-width: 0;
}

body {
  overflow-x: hidden;
}

.chat-scroll {
  overflow-x: hidden;
}

.timeline-body,
.editable-text,
.reasoning,
.reasoning-body,
.node-tools,
.composer-node .timeline-body,
.composer-box,
.params,
.param-group {
  min-width: 0;
  max-width: 100%;
}

.editable-text,
.reasoning-body,
.prefix-hint,
.prefix-textarea,
.composer textarea,
.param-textarea,
.param-input {
  overflow-wrap: anywhere;
  word-break: break-word;
}

.reasoning-body {
  max-height: min(42vh, 360px);
  overflow: auto;
  padding-right: 8px;
}

.editable-text pre,
.reasoning-body pre,
.timeline-body pre {
  max-width: 100%;
  overflow-x: auto;
  white-space: pre;
}

.editable-text code,
.reasoning-body code,
.timeline-body code {
  overflow-wrap: anywhere;
  word-break: break-word;
}

.branch-menu {
  max-width: min(260px, calc(100vw - 32px));
}


/* ===== timeline role/input refinement ===== */
.timeline-node,
.composer-node {
  grid-template-columns: 92px minmax(0, 1fr);
  gap: 24px;
}

.timeline-node::before,
.composer-node::before {
  left: 104px;
}

.timeline-role {
  position: relative;
  z-index: 1;
  white-space: nowrap;
  text-align: right;
  overflow: visible;
  font-size: 11px;
  letter-spacing: 0.06em;
  padding-right: 0;
}

.composer-node .timeline-role {
  padding-top: 5px;
}

.composer-node .composer-box {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  min-height: 46px;
  border-bottom: 1px solid var(--line-2);
  padding: 8px 0 12px;
  background: transparent;
}

.composer-node .composer-box:focus-within {
  border-color: var(--clay);
  box-shadow: 0 2px 0 var(--clay-soft);
}

.composer-node textarea,
#msgInput {
  display: block;
  flex: 1 1 auto;
  width: 100%;
  min-width: 0;
  min-height: 28px;
  max-height: 160px;
  border: none;
  background: transparent;
  color: var(--ink);
  font-family: inherit;
  font-size: 15px;
  line-height: 1.65;
  resize: none;
  outline: none;
  padding: 3px 0;
}

.composer-node textarea::placeholder,
#msgInput::placeholder {
  color: var(--ink-4);
}

@media (max-width: 900px) {
  .timeline-node,
  .composer-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .timeline-node::before,
  .composer-node::before {
    left: 6px;
  }

  .timeline-role {
    text-align: left;
  }
}


/* ===== immersive control polish ===== */
.session-item {
  background: color-mix(in srgb, var(--card) 76%, transparent);
  border-color: color-mix(in srgb, var(--line) 72%, transparent);
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--card) 74%, transparent);
}

.session-item:hover {
  background: color-mix(in srgb, var(--card-2) 82%, var(--clay-soft));
  border-color: var(--line-2);
  transform: translateY(-1px);
}

.session-item.active {
  background: color-mix(in srgb, var(--clay-soft) 72%, var(--card));
  border-color: var(--clay-line);
}

[data-theme="dark"] .session-item {
  background: color-mix(in srgb, var(--card) 72%, #000 10%);
  border-color: var(--line);
  box-shadow: inset 0 1px 0 rgba(255,255,255,0.025);
}

[data-theme="dark"] .session-item:hover {
  background: color-mix(in srgb, var(--card-2) 82%, var(--clay-soft));
}

[data-theme="dark"] .session-item.active {
  background: color-mix(in srgb, var(--clay-soft) 55%, var(--card));
}

.chat-inner {
  max-width: 940px;
}

.timeline-node,
.composer-node {
  grid-template-columns: 72px minmax(0, 1fr);
  gap: 18px;
}

.timeline-node::before,
.composer-node::before {
  left: 86px;
  opacity: .72;
}

.timeline-role {
  color: color-mix(in srgb, var(--ink-3) 82%, var(--paper));
  font-size: 10px;
  letter-spacing: .075em;
  text-align: right;
  transform: translateY(1px);
}

.timeline-node {
  padding: 17px 0 22px;
}

.timeline-body {
  padding-left: 2px;
}

.reasoning-composer {
  margin-top: 12px;
  border-left: 2px solid color-mix(in srgb, var(--clay) 58%, transparent);
  padding-left: 12px;
  color: var(--ink-2);
  transition: border-color .35s var(--ease), opacity .35s var(--ease);
}

.reasoning-composer summary {
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: baseline;
  gap: 9px;
  color: var(--clay-deep);
  font-size: 12px;
  font-weight: 600;
  letter-spacing: .04em;
  user-select: none;
}

.reasoning-composer summary::-webkit-details-marker {
  display: none;
}

.reasoning-composer summary::before {
  content: '+';
  width: 16px;
  height: 16px;
  border-radius: 999px;
  display: inline-grid;
  place-items: center;
  border: 1px solid var(--clay-line);
  color: var(--clay-deep);
  font-size: 12px;
  line-height: 1;
  transition: transform .35s var(--spring), background .35s var(--ease);
}

.reasoning-composer[open] summary::before {
  content: '−';
  background: var(--clay-soft);
  transform: rotate(180deg);
}

.reasoning-composer.is-suggested {
  border-left-color: var(--clay);
}

.reasoning-composer-note {
  color: var(--ink-3);
  font-size: 11px;
  font-weight: 400;
  letter-spacing: 0;
}

.reasoning-composer textarea {
  width: 100%;
  margin-top: 10px;
  min-height: 76px;
  max-height: 180px;
  resize: vertical;
  border: none;
  border-top: 1px solid var(--line);
  background: transparent;
  color: var(--ink);
  padding: 10px 0 4px;
  font: inherit;
  font-size: 13px;
  line-height: 1.65;
  outline: none;
  transition: border-color .3s var(--ease);
}

.reasoning-composer textarea:focus {
  border-top-color: var(--clay);
}

.reasoning-composer textarea::placeholder {
  color: var(--ink-4);
}

.param-select,
.param-input,
.param-textarea,
.seg,
.advanced summary,
.reasoning-composer summary,
.send-btn,
.new-chat-btn,
.theme-toggle button,
.branch-chip,
.branch-menu button {
  transition: background-color .28s var(--ease), border-color .28s var(--ease), color .28s var(--ease), box-shadow .28s var(--ease), transform .28s var(--spring), opacity .28s var(--ease);
}

.param-select:hover,
.param-input:hover,
.param-textarea:hover {
  border-color: color-mix(in srgb, var(--clay) 45%, var(--line-2));
  background: color-mix(in srgb, var(--card) 88%, var(--clay-soft));
}

.param-select:focus,
.param-input:focus,
.param-textarea:focus {
  transform: translateY(-1px);
}

.seg {
  box-shadow: inset 0 0 0 1px color-mix(in srgb, var(--line) 78%, transparent);
}

.seg button:hover {
  color: var(--clay-deep);
  background: color-mix(in srgb, var(--clay-soft) 70%, transparent);
}

.seg button.on {
  transform: translateY(-1px);
}

.advanced summary:hover,
.reasoning-composer summary:hover {
  color: var(--clay);
}

.param-select {
  cursor: pointer;
}

@media (max-width: 900px) {
  .timeline-node,
  .composer-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .timeline-node::before,
  .composer-node::before {
    left: 6px;
  }

  .timeline-role {
    text-align: left;
  }
}

/* ===== integrated timeline polish v3 ===== */
.chat-inner {
  max-width: 980px;
}

.timeline-node,
.composer-node {
  grid-template-columns: 86px minmax(0, 1fr);
  gap: 22px;
}

.timeline-node::before,
.composer-node::before {
  left: 101px;
  opacity: .58;
  background: linear-gradient(180deg, color-mix(in srgb, var(--line-2) 76%, transparent), transparent 92%);
}

.timeline-role {
  color: color-mix(in srgb, var(--ink-3) 78%, var(--paper));
  font-size: 10.5px;
  letter-spacing: .06em;
  line-height: 1.5;
  text-align: right;
  padding-right: 2px;
}

.timeline-body {
  padding-left: 8px;
}

.timeline-node {
  padding: 19px 0 24px;
}

.timeline-node:hover .timeline-role,
.timeline-node.is-selected .timeline-role,
.composer-node:focus-within .timeline-role {
  color: var(--clay-deep);
}

.timeline-node:hover,
.timeline-node.is-selected {
  border-bottom-color: color-mix(in srgb, var(--clay-line) 34%, var(--line));
}

.editable-text {
  font-size: 16.5px;
  line-height: 1.82;
}

.local-pending {
  animation: fadeInUp .28s var(--ease) both;
}

.composer-node {
  margin-top: 0;
  padding-top: 24px;
}

.composer-node .timeline-body {
  padding-left: 8px;
}

.composer-node .next-headline {
  margin-bottom: 12px;
}

.next-kicker {
  font-size: 16px;
}

.next-note {
  color: color-mix(in srgb, var(--ink-3) 90%, var(--clay));
}

.composer-node .composer-box {
  min-height: 50px;
  padding: 7px 0 11px;
  border-bottom-color: color-mix(in srgb, var(--line-2) 82%, transparent);
}

.composer-node .composer-box:focus-within {
  border-color: var(--clay);
  box-shadow: 0 1px 0 var(--clay), 0 8px 24px -22px var(--clay);
}

.send-btn {
  border-radius: 999px;
  background: color-mix(in srgb, var(--clay) 94%, var(--ink));
}

.send-btn:disabled {
  background: var(--line-2);
  color: var(--ink-3);
  border-color: var(--line-2);
  opacity: .8;
}

.reasoning-composer {
  margin-top: 10px;
  padding-left: 13px;
  border-left-color: color-mix(in srgb, var(--clay) 48%, var(--line));
}

.reasoning-composer[open] {
  border-left-color: var(--clay);
}

.params {
  grid-template-columns: minmax(220px, 1.2fr) minmax(150px, .55fr) minmax(180px, .8fr) minmax(150px, .65fr);
  align-items: end;
  gap: 14px 16px;
  margin-top: 17px;
}

.param-group.system {
  grid-column: 1 / -1;
}

.advanced {
  grid-column: 1 / -1;
}

.param-input,
.param-select,
.param-textarea {
  border-radius: 9px;
  background: color-mix(in srgb, var(--card) 76%, transparent);
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--card) 74%, transparent);
}

.param-select {
  appearance: none;
  background-image:
    linear-gradient(45deg, transparent 50%, currentColor 50%),
    linear-gradient(135deg, currentColor 50%, transparent 50%);
  background-position:
    calc(100% - 17px) 50%,
    calc(100% - 12px) 50%;
  background-size: 5px 5px, 5px 5px;
  background-repeat: no-repeat;
  padding-right: 32px;
}

.param-select:hover,
.param-select:focus {
  color: var(--clay-deep);
}

.seg {
  position: relative;
  border-radius: 999px;
  padding: 4px;
  background: color-mix(in srgb, var(--card-2) 74%, transparent);
}

.seg button {
  border-radius: 999px;
  padding: 7px 10px;
}

.seg button.on {
  background: color-mix(in srgb, var(--card) 88%, var(--clay-soft));
  box-shadow: 0 1px 2px rgba(60, 50, 38, .04), 0 7px 20px -16px var(--clay);
}

.session-item .del {
  border: 1px solid transparent;
  background: transparent;
}

[data-theme="dark"] .session-item,
[data-theme="dark"] .session-item.active,
[data-theme="dark"] .session-item:hover {
  color: var(--ink);
}

[data-theme="dark"] .session-item .title,
[data-theme="dark"] .session-item.active .title {
  color: var(--ink-2);
}

[data-theme="dark"] .session-item.active .title {
  color: var(--ink);
}

[data-theme="dark"] .session-item .del {
  color: var(--ink-3);
  background: transparent;
}

[data-theme="dark"] .session-item:hover .del {
  background: color-mix(in srgb, var(--card-2) 70%, transparent);
  border-color: var(--line-2);
}

[data-theme="dark"] .session-item .del:hover {
  background: var(--err);
  color: #1a1512;
  border-color: var(--err);
}

[data-theme="dark"] .branch-menu {
  background: color-mix(in srgb, var(--card) 92%, #000);
  border-color: var(--line-2);
  box-shadow: 0 18px 42px rgba(0, 0, 0, .34);
}

[data-theme="dark"] .param-input,
[data-theme="dark"] .param-select,
[data-theme="dark"] .param-textarea,
[data-theme="dark"] .seg {
  background-color: color-mix(in srgb, var(--card) 86%, #000 8%);
}

@media (max-width: 900px) {
  .timeline-node,
  .composer-node {
    grid-template-columns: 1fr;
    gap: 8px;
  }

  .timeline-node::before,
  .composer-node::before {
    left: 6px;
  }

  .timeline-role {
    text-align: left;
    padding-right: 0;
  }

  .timeline-body,
  .composer-node .timeline-body {
    padding-left: 0;
  }

  .params {
    grid-template-columns: 1fr;
  }
}

/* ===== refinement v4: compact header, theme switch, branch/edit, stream cursor ===== */
.main-head {
  display: none;
}

.status-line {
  min-height: 22px;
  padding: 0 28px;
  margin-top: -2px;
  border-bottom: 1px solid color-mix(in srgb, var(--line) 70%, transparent);
  background: color-mix(in srgb, var(--paper) 86%, transparent);
  display: flex;
  align-items: center;
  gap: 8px;
  flex-wrap: wrap;
  color: var(--ink-3);
  font-size: 11px;
}

.status-line:empty {
  display: none;
}

.session-sub .tag .pill.neutral {
  background: var(--ink-4);
}

.empty-sessions {
  text-align: center;
  color: var(--ink-4);
  font-size: 12px;
  padding: 26px 0;
}

.theme-toggle {
  display: none;
}

.theme-switch {
  width: 54px;
  height: 30px;
  padding: 0;
  border: 1px solid color-mix(in srgb, var(--line-2) 82%, transparent);
  border-radius: 999px;
  background: color-mix(in srgb, var(--card) 82%, transparent);
  color: var(--ink-2);
  cursor: pointer;
  display: inline-grid;
  place-items: center;
  box-shadow: inset 0 1px 0 color-mix(in srgb, var(--card) 76%, transparent), var(--shadow-sm);
  transition: background-color .35s var(--ease), border-color .35s var(--ease), box-shadow .35s var(--ease), transform .35s var(--spring);
}

.theme-switch:hover {
  transform: translateY(-1px);
  border-color: color-mix(in srgb, var(--clay) 44%, var(--line-2));
}

.theme-switch-track {
  position: relative;
  width: 46px;
  height: 22px;
  display: block;
}

.theme-switch-thumb {
  position: absolute;
  left: 0;
  top: 0;
  width: 22px;
  height: 22px;
  border-radius: 999px;
  display: grid;
  place-items: center;
  background: var(--paper);
  color: var(--clay-deep);
  box-shadow: 0 2px 8px rgba(60, 50, 38, .14);
  transition: transform .45s var(--spring), background-color .35s var(--ease), color .35s var(--ease);
}

.theme-switch svg {
  grid-area: 1 / 1;
  width: 13px;
  height: 13px;
  transition: opacity .25s var(--ease), transform .35s var(--spring);
}

.theme-switch .moon {
  opacity: 0;
  transform: rotate(-25deg) scale(.78);
}

.theme-switch[data-theme="dark"] .theme-switch-thumb {
  transform: translateX(24px);
  background: color-mix(in srgb, var(--card) 88%, #000);
  color: var(--clay);
}

.theme-switch[data-theme="dark"] .sun {
  opacity: 0;
  transform: rotate(35deg) scale(.78);
}

.theme-switch[data-theme="dark"] .moon {
  opacity: 1;
  transform: rotate(0) scale(1);
}

.branch-wrap {
  z-index: 18;
}

.branch-chip {
  padding: 4px 9px;
  border-color: color-mix(in srgb, var(--clay-line) 70%, var(--line));
  background: color-mix(in srgb, var(--paper) 42%, var(--clay-soft));
  box-shadow: none;
}

.branch-chip:hover,
.branch-wrap.open .branch-chip {
  color: var(--clay-deep);
  background: color-mix(in srgb, var(--clay-soft) 84%, var(--card));
  border-color: var(--clay-line);
}

.branch-menu {
  left: auto;
  right: 0;
  min-width: 150px;
  border-radius: 10px;
  background: color-mix(in srgb, var(--card) 94%, var(--paper));
  backdrop-filter: blur(14px) saturate(1.2);
  -webkit-backdrop-filter: blur(14px) saturate(1.2);
}

.branch-menu button {
  border-radius: 7px;
  padding: 7px 9px;
  color: var(--ink-2);
}

.branch-menu button:hover {
  color: var(--clay-deep);
}

.edit-hint {
  transition: color .25s var(--ease), opacity .25s var(--ease);
}

.timeline-node.is-editing .edit-hint {
  color: var(--clay-deep);
  opacity: 1;
}

.typing-cursor {
  display: inline-block;
  width: 8px;
  height: 1.22em;
  margin-left: 3px;
  vertical-align: -0.2em;
  border-radius: 99px;
  background: color-mix(in srgb, var(--clay) 88%, #fff 12%);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--clay-soft) 88%, transparent), 0 0 18px color-mix(in srgb, var(--clay) 36%, transparent);
  animation: cursorPulse 1s var(--ease-soft) infinite;
}

.streaming .timeline-body {
  position: relative;
}

.streaming .timeline-body::after {
  content: '';
  position: absolute;
  left: -14px;
  top: .55em;
  width: 6px;
  height: 6px;
  border-radius: 999px;
  background: var(--clay);
  box-shadow: 0 0 0 6px var(--clay-soft);
  animation: streamGlow 1.4s var(--ease-soft) infinite;
}

.param-select {
  height: 38px;
  border-radius: 999px;
  border-color: color-mix(in srgb, var(--line-2) 86%, transparent);
  background-color: color-mix(in srgb, var(--card) 86%, transparent);
  background-image:
    linear-gradient(45deg, transparent 50%, color-mix(in srgb, var(--ink-3) 86%, var(--clay)) 50%),
    linear-gradient(135deg, color-mix(in srgb, var(--ink-3) 86%, var(--clay)) 50%, transparent 50%),
    linear-gradient(90deg, transparent, color-mix(in srgb, var(--line) 68%, transparent));
  background-position:
    calc(100% - 18px) 51%,
    calc(100% - 13px) 51%,
    calc(100% - 34px) 50%;
  background-size: 5px 5px, 5px 5px, 1px 18px;
  background-repeat: no-repeat;
  padding: 8px 38px 8px 14px;
}

.param-select:hover {
  border-color: color-mix(in srgb, var(--clay) 48%, var(--line-2));
  box-shadow: 0 8px 26px -24px var(--clay), inset 0 1px 0 color-mix(in srgb, var(--card) 74%, transparent);
}

.param-select:focus {
  border-color: var(--clay);
  box-shadow: 0 0 0 3px var(--clay-soft), 0 10px 26px -22px var(--clay);
}

.param-select option {
  background: var(--card);
  color: var(--ink);
}

.param-input,
.param-textarea,
.reasoning-composer textarea,
.composer-node textarea,
#msgInput {
  caret-color: var(--clay);
}

[data-theme="dark"] .status-line {
  background: color-mix(in srgb, var(--paper) 90%, #000);
  border-bottom-color: var(--line);
}

[data-theme="dark"] .theme-switch {
  background: color-mix(in srgb, var(--card) 88%, #000 8%);
  border-color: var(--line-2);
  box-shadow: inset 0 1px 0 rgba(255,255,255,.025), var(--shadow-sm);
}

[data-theme="dark"] .branch-chip {
  background: color-mix(in srgb, var(--card) 76%, var(--clay-soft));
  border-color: color-mix(in srgb, var(--clay-line) 58%, var(--line));
  color: var(--ink-2);
}

[data-theme="dark"] .branch-chip:hover,
[data-theme="dark"] .branch-wrap.open .branch-chip {
  background: color-mix(in srgb, var(--card-2) 84%, var(--clay-soft));
  color: var(--clay);
}

[data-theme="dark"] .branch-menu button {
  color: var(--ink-2);
}

[data-theme="dark"] .branch-menu button:hover {
  background: color-mix(in srgb, var(--clay-soft) 70%, transparent);
  color: var(--clay);
}

[data-theme="dark"] .param-select {
  background-color: color-mix(in srgb, var(--card) 88%, #000 8%);
  color: var(--ink);
  border-color: var(--line-2);
}

[data-theme="dark"] .param-select:hover,
[data-theme="dark"] .param-select:focus {
  color: var(--clay);
}

[data-theme="dark"] .param-select option {
  background: #232019;
  color: var(--ink);
}

[data-theme="dark"] .typing-cursor {
  background: var(--clay);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--clay-soft) 80%, transparent), 0 0 20px color-mix(in srgb, var(--clay) 42%, transparent);
}

@keyframes cursorPulse {
  0%, 100% { opacity: .28; transform: translateY(1px) scaleY(.72); }
  45% { opacity: 1; transform: translateY(0) scaleY(1); }
}

@keyframes streamGlow {
  0%, 100% { opacity: .45; transform: scale(.82); }
  50% { opacity: 1; transform: scale(1); }
}

@media (max-width: 900px) {
  .status-line {
    padding: 0 16px;
  }

  .branch-menu {
    left: 0;
    right: auto;
  }
}

/* ===== message-level metadata + assistant branch compose ===== */
.branch-chip {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  max-width: min(520px, 72vw);
}

.branch-meta {
  display: inline-flex;
  align-items: center;
  min-width: 0;
  color: var(--ink-3);
  font-size: 10.5px;
  font-weight: 500;
  letter-spacing: 0;
  white-space: nowrap;
}

.branch-chip:hover .branch-meta,
.branch-wrap.open .branch-meta {
  color: color-mix(in srgb, var(--clay-deep) 72%, var(--ink-2));
}

.branch-compose-line {
  display: none;
  align-items: center;
  gap: 9px;
  margin: 0 0 10px;
  color: var(--ink-3);
  font-size: 12px;
}

.branch-compose-line strong {
  color: var(--clay-deep);
  font-weight: 650;
}

.branch-compose-line button {
  border: 1px solid var(--line);
  border-radius: 999px;
  background: color-mix(in srgb, var(--card) 86%, transparent);
  color: var(--ink-2);
  padding: 3px 10px;
  font: inherit;
  font-size: 11px;
  cursor: pointer;
  transition: background-color .28s var(--ease), border-color .28s var(--ease), color .28s var(--ease), transform .28s var(--spring);
}

.branch-compose-line button:hover {
  transform: translateY(-1px);
  color: var(--clay-deep);
  border-color: var(--clay-line);
  background: color-mix(in srgb, var(--clay-soft) 72%, var(--card));
}

.composer-node.branch-compose .branch-compose-line {
  display: flex;
}

.composer-node.branch-compose .composer-box {
  display: none;
}

.composer-node.branch-compose .reasoning-composer {
  margin-top: 0;
}

.composer-node.branch-compose .next-note::after {
  content: ' · 只填写 reasoning_content';
  color: var(--clay-deep);
}

[data-theme="dark"] .branch-meta {
  color: var(--ink-3);
}

[data-theme="dark"] .branch-compose-line button {
  background: color-mix(in srgb, var(--card) 82%, #000 8%);
  border-color: var(--line-2);
  color: var(--ink-2);
}

@media (max-width: 640px) {
  .branch-chip {
    max-width: 78vw;
    flex-wrap: wrap;
  }

  .branch-meta {
    width: 100%;
  }
}

/* Keep branch send available while hiding only the normal text field. */
.composer-node.branch-compose .composer-box {
  display: flex;
  justify-content: flex-end;
  min-height: 0;
  padding: 0 0 8px;
  border-bottom: 0;
}

.composer-node.branch-compose #msgInput {
  display: none;
}

.composer-node.branch-compose .send-btn {
  width: 38px;
  height: 38px;
}