/* ============================================================
   HydraChat · layout.css
   极简外壳 / 顶栏 / 对话区 / 居中弹窗
   ============================================================ */

.app {
  display: grid;
  grid-template-rows: 52px 1fr;
  height: 100vh;
  height: 100dvh;
  overflow: hidden;
}

/* ---------------- 顶栏 ---------------- */
.topbar {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: var(--sp-4);
  padding: 0 var(--sp-4);
  background: color-mix(in srgb, var(--surface) 82%, transparent);
  backdrop-filter: blur(16px) saturate(1.3);
  border-bottom: 1px solid var(--border);
  z-index: 40;
}
.topbar__left  { display: flex; align-items: center; gap: var(--sp-2); min-width: 0; }
.topbar__center{ display: flex; justify-content: center; }
.topbar__right { display: flex; align-items: center; justify-content: flex-end; gap: 2px; }

.brand__logo {
  width: 22px; height: 22px;
  display: block;
  flex: none;
}
.brand__logo svg { width: 100%; height: 100%; display: block; }
.brand__name { font-weight: 600; letter-spacing: -.01em; font-size: 14px; }

/* 状态徽标 */
.status-pill {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 11px;
  border-radius: 999px;
  background: color-mix(in srgb, var(--ok) 9%, transparent);
  font-size: 12px;
  font-weight: 550;
  color: var(--ok);
  white-space: nowrap;
  transition: background .3s ease, color .3s ease;
}
.status-dot {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--ok);
  animation: statusPulse 2.4s var(--ease-smooth) infinite;
}
@keyframes statusPulse {
  0%   { box-shadow: 0 0 0 0 color-mix(in srgb, var(--ok) 45%, transparent); }
  70%  { box-shadow: 0 0 0 6px color-mix(in srgb, var(--ok) 0%, transparent); }
  100% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--ok) 0%, transparent); }
}
.status-pill.is-error { background: color-mix(in srgb, var(--err) 10%, transparent); color: var(--err); }
.status-pill.is-error .status-dot { background: var(--err); }
.status-pill.is-checking { color: var(--text-3); background: var(--surface-3); }
.status-pill.is-checking .status-dot { background: var(--text-3); animation: none; }
.status-meta { opacity: .6; font-family: "JetBrains Mono", Consolas, monospace; font-size: 10.5px; }

/* ---------------- 对话区 ---------------- */
.chat {
  position: relative;
  display: grid;
  grid-template-rows: 1fr auto;
  /* 显式单列：否则 grid 自动布局会把 .chat__scroll 与 .composer
     分配到两列（两者都写了 grid-row:1），输入框整块被推到右边。 */
  grid-template-columns: minmax(0, 1fr);
  min-height: 0;
  /* 需高于顶栏(40)：composer 的模型下拉要能完整盖住顶栏，
     否则顶栏的 backdrop-filter 会把菜单顶部糊掉。
     这里不加 overflow:hidden —— 它会把向上展开的菜单裁掉。 */
  z-index: 50;
}
.chat__scroll {
  grid-column: 1;
  overflow-y: auto;
  overflow-x: hidden;
  scroll-behavior: smooth;
  padding: var(--chat-pad);
  display: flex;
  flex-direction: column;
}
.chat__thread {
  width: 100%;
  max-width: var(--bubble-max);
  margin: 0 auto;
  margin-top: auto;          /* 消息贴底堆叠 */
  display: flex;
  flex-direction: column;
  gap: var(--sp-4);
  flex: 0 0 auto;
}

/* 空态：输入框精确居中 */
.chat.is-empty { grid-template-rows: 1fr; }
.chat.is-empty .chat__scroll { grid-row: 1; grid-column: 1; pointer-events: none; }
.chat.is-empty .composer {
  grid-row: 1;
  grid-column: 1;
  align-self: center;
  border-top: none;
  background: none;
  backdrop-filter: none;
  padding-bottom: 0;
}
.chat.is-empty .composer__inner { max-width: 640px; margin: 0 auto; width: 100%; }
.chat.is-empty .composer__hint { opacity: 0; }

/* 空态 hero —— 悬浮在输入框正上方 */
.composer__inner { position: relative; }
.empty-hero {
  position: absolute;
  bottom: calc(100% + 16px);
  left: 0; right: 0;
  display: flex;
  justify-content: center;
  pointer-events: none;
  opacity: 1;
  transform: translateY(0);
  transition: opacity .32s var(--ease-smooth), transform .5s var(--ease-smooth);
}
.empty-hero__inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--sp-2);
  text-align: center;
}
.empty-hero__canvas {
  width: 72px; height: 72px;
  image-rendering: pixelated;
  border-radius: 18px;
  background: var(--surface);
  border: 1px solid var(--border);
  box-shadow: var(--shadow-2);
}
.empty-hero__title { font-size: 17px; font-weight: 600; letter-spacing: -.01em; }
.empty-hero__sub { font-size: 12.5px; color: var(--text-3); }
.chat:not(.is-empty) .empty-hero {
  opacity: 0;
  transform: translateY(16px) scale(.96);
}

/* ---------------- 输入区 ---------------- */
.composer {
  border-top: 1px solid var(--border);
  background: color-mix(in srgb, var(--surface) 86%, transparent);
  backdrop-filter: blur(16px);
  padding: var(--sp-3) var(--chat-pad) var(--sp-4);
  display: flex;
  flex-direction: column;
  gap: 6px;
  z-index: 60;          /* 需高于顶栏，模型下拉才能完整展开 */
}
.composer__inner {
  width: 100%;
  max-width: var(--bubble-max);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 6px;
}
.composer__tools {
  display: flex;
  align-items: center;
  gap: var(--sp-2);
}
.composer__spacer { flex: 1; }
.composer__input {
  display: flex;
  align-items: flex-end;
  gap: var(--sp-2);
  padding: 7px 7px 7px 14px;
  border-radius: var(--radius);
  background: var(--surface);
  border: 1px solid var(--border);
  transition: border-color .2s ease, box-shadow .25s ease;
}
.composer__input:focus-within {
  border-color: var(--accent-line);
  box-shadow: 0 0 0 3px var(--accent-soft);
}
.composer__input textarea {
  flex: 1;
  border: none; outline: none; background: none;
  resize: none;
  font-size: 13.5px;
  line-height: 1.65;
  max-height: 150px;
  padding: 5px 0;
}
.composer__input textarea::placeholder { color: var(--text-3); }
.composer__hint {
  text-align: center;
  font-size: 11px;
  color: var(--text-3);
  transition: opacity .3s ease;
}
.chat:not(.is-empty) .composer__hint { opacity: .75; }

.send-btn {
  width: 34px; height: 34px;
  border-radius: 10px;
  display: grid; place-items: center;
  background: var(--accent);
  color: #fff;
  flex: none;
  position: relative;
  overflow: hidden;
  transition: filter .18s ease, box-shadow .2s ease, transform .18s var(--ease-spring), opacity .2s ease;
}
.send-btn:hover { filter: brightness(1.08); box-shadow: var(--shadow-2); }
.send-btn .ico { fill: currentColor; stroke: none; }

/* ---------------- 遮罩 + 弹窗 ---------------- */
.scrim {
  position: fixed;
  inset: 0;
  z-index: 100;
  background: rgba(16, 20, 28, .34);
  backdrop-filter: blur(3px);
  opacity: 0;
  transition: opacity .28s var(--ease-smooth);
}
.scrim.is-open { opacity: 1; }

.modal {
  position: fixed;
  inset: 0;
  z-index: 110;
  display: grid;
  place-items: center;
  padding: var(--sp-5);
  pointer-events: none;
}
.modal[hidden] { display: none; }

.modal__card {
  width: min(var(--modal-w), 100%);
  max-height: min(84vh, 760px);
  display: grid;
  grid-template-rows: auto auto 1fr auto;
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-3);
  overflow: hidden;
  pointer-events: auto;
  opacity: 0;
  transform: translateY(16px) scale(.96);
  transition: opacity .3s var(--ease-smooth), transform .38s var(--ease-spring);
}
.modal.is-open .modal__card { opacity: 1; transform: none; }
.modal--sessions .modal__card { --modal-w: 460px; }

/* 弹窗头 */
.modal__head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--sp-3) var(--sp-3) var(--sp-3) var(--sp-4);
  border-bottom: 1px solid var(--border);
}
.modal__title { font-size: 14px; font-weight: 600; letter-spacing: -.01em; }

/* 弹窗体 */
.modal__body {
  overflow-y: auto;
  overflow-x: hidden;
  padding: var(--sp-3);
  display: flex;
  flex-direction: column;
  gap: var(--sp-3);
}
.modal--sessions .modal__body { gap: var(--sp-2); }

/* 弹窗脚 */
.modal__foot {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: var(--sp-2);
  padding: var(--sp-2) var(--sp-3);
  border-top: 1px solid var(--border);
  background: var(--surface-2);
}

/* 会话分区 */
.modal__section-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 7px 8px;
  color: var(--text-3);
  font-size: 11.5px;
  font-weight: 600;
  letter-spacing: .04em;
  text-transform: uppercase;
  cursor: pointer;
  border-radius: 7px;
  user-select: none;
  transition: background .18s ease, color .18s ease;
}
.modal__section-head:hover { color: var(--text-2); background: var(--surface-2); }
.modal__section-head .caret { transition: transform var(--dur-collapse) var(--ease-smooth); }
.modal__section.is-collapsed .caret { transform: rotate(-90deg); }

/* 会话分区折叠 —— 同样用 grid-rows 0fr→1fr */
.modal__section-body {
  display: grid;
  grid-template-rows: 1fr;
  transition: grid-template-rows var(--dur-collapse) var(--ease-smooth);
}
.modal__section.is-collapsed .modal__section-body { grid-template-rows: 0fr; }
.modal__section-body > .group__inner {
  overflow: hidden;
  min-height: 0;
  opacity: 1;
  transition: opacity calc(var(--dur-collapse) * .7) ease;
}
.modal__section.is-collapsed .modal__section-body > .group__inner { opacity: 0; }

/* ---------------- Tabs ---------------- */
.tabs {
  display: flex;
  gap: 2px;
  padding: var(--sp-2) var(--sp-2) 0;
  border-bottom: 1px solid var(--border);
  overflow-x: auto;
}
.tab {
  position: relative;
  padding: 7px 11px 9px;
  font-size: 13px;
  color: var(--text-3);
  border-radius: 8px 8px 0 0;
  white-space: nowrap;
  transition: color .2s ease, background .2s ease;
}
.tab:hover { color: var(--text-2); background: var(--surface-2); }
.tab.is-active { color: var(--accent); font-weight: 560; }
.tab.is-active::after {
  content: "";
  position: absolute;
  left: 10px; right: 10px; bottom: -1px;
  height: 2px;
  border-radius: 2px 2px 0 0;
  background: var(--accent);
  animation: tabIn .3s var(--ease-spring);
}
@keyframes tabIn { from { transform: scaleX(.2); opacity: 0; } to { transform: scaleX(1); opacity: 1; } }

.tab-panel { display: none; flex-direction: column; gap: var(--sp-3); }
.tab-panel.is-active { display: flex; animation: panelIn .3s var(--ease-smooth); }
@keyframes panelIn { from { opacity: 0; transform: translateY(6px); } to { opacity: 1; transform: none; } }

/* ---------------- Toast ---------------- */
.toast-host {
  position: fixed;
  bottom: 22px; left: 50%;
  transform: translateX(-50%);
  z-index: 9995;
  display: flex; flex-direction: column; gap: 8px;
  align-items: center;
  pointer-events: none;
}
.toast {
  padding: 9px 16px;
  border-radius: 999px;
  background: var(--text);
  color: var(--bg);
  font-size: 13px;
  box-shadow: var(--shadow-3);
  animation: toastIn .34s var(--ease-spring);
}
.toast.is-out { animation: toastOut .26s var(--ease-smooth) forwards; }
@keyframes toastIn  { from { opacity: 0; transform: translateY(14px) scale(.94); } to { opacity: 1; transform: none; } }
@keyframes toastOut { to { opacity: 0; transform: translateY(10px) scale(.96); } }

/* ---------------- 响应式 ---------------- */
@media (max-width: 640px) {
  .topbar { grid-template-columns: auto 1fr auto; }
  .brand__name { display: none; }
  .status-meta { display: none; }
  .modal { padding: var(--sp-3); }
}