/* ==========================================================================
   AI FIX NHANH — a calm, dark-first chat surface
   ========================================================================== */

:root {
  --bg: #07080b;
  --bg-soft: #0c0e13;
  --panel: rgba(255, 255, 255, 0.035);
  --panel-strong: rgba(255, 255, 255, 0.06);
  --line: rgba(255, 255, 255, 0.08);
  --line-strong: rgba(255, 255, 255, 0.14);
  --ink: #eceff6;
  --ink-soft: #b3bbcc;
  --ink-muted: #7b8497;
  --accent: #8b7dff;
  --accent-2: #43dcc8;
  --accent-ink: #0a0b10;
  --danger: #ff7a7a;
  --radius: 16px;
  --radius-sm: 10px;
  --shadow: 0 24px 60px -30px rgba(0, 0, 0, 0.9);
  --font: "Inter", ui-sans-serif, system-ui, -apple-system, "Segoe UI", sans-serif;
  --mono: "JetBrains Mono", ui-monospace, SFMono-Regular, Menlo, monospace;
  --measure: 46rem;
}

html[data-theme="light"] {
  --bg: #f0ece3;
  --bg-soft: #fdfbf6;
  --panel: rgba(16, 18, 24, 0.035);
  --panel-strong: rgba(16, 18, 24, 0.06);
  --line: rgba(16, 18, 24, 0.09);
  --line-strong: rgba(16, 18, 24, 0.16);
  --ink: #14161c;
  --ink-soft: #464c58;
  --ink-muted: #7c8494;
  --accent: #5b46e5;
  --accent-2: #0f9f8f;
  --accent-ink: #ffffff;
  --shadow: 0 20px 50px -28px rgba(24, 22, 40, 0.35);
}

* { box-sizing: border-box; }

[hidden] { display: none !important; }

html, body { height: 100%; }

/* Never let anything drag the shell sideways (wide code, focus scroll, zoom). */
html { overflow: hidden; overflow: clip; overscroll-behavior: none; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--ink);
  font-family: var(--font);
  font-size: 15px;
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
  overflow: hidden;
  overflow: clip;
  overscroll-behavior: none;
  position: fixed;
  inset: 0;
}

/* soft aurora wash behind everything ---------------------------------------- */
.aurora {
  position: fixed;
  inset: -20% -10% auto -10%;
  height: 70vh;
  background:
    radial-gradient(45% 55% at 18% 10%, rgba(139, 125, 255, 0.22), transparent 70%),
    radial-gradient(40% 50% at 82% 0%, rgba(67, 220, 200, 0.16), transparent 70%),
    radial-gradient(35% 45% at 55% 25%, rgba(255, 110, 180, 0.10), transparent 70%);
  filter: blur(20px);
  pointer-events: none;
  z-index: 0;
}

html[data-theme="light"] .aurora { opacity: 0.55; }

html[data-theme="light"] .sidebar {
  background: #fbf9f3;
}

html[data-theme="light"] .field {
  background: #fffefb;
}

html[data-theme="light"] .bubble {
  color: #17142a;
}

html[data-theme="light"] .code {
  background: #f4f2ec;
}

/* layout ------------------------------------------------------------------- */
.app {
  position: fixed;
  inset: 0;
  z-index: 1;
  display: grid;
  grid-template-columns: 278px minmax(0, 1fr);
  grid-template-rows: minmax(0, 1fr);
  height: 100dvh;
  height: 100%;
  width: 100%;
  overflow: hidden;
}

/* sidebar ------------------------------------------------------------------ */
.sidebar {
  display: flex;
  flex-direction: column;
  gap: 14px;
  padding: 20px 14px 14px;
  border-right: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg-soft) 82%, transparent);
  backdrop-filter: blur(18px);
}

.brand {
  display: flex;
  align-items: center;
  gap: 11px;
  padding: 2px 8px 8px;
}

.mark {
  flex: none;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  background: conic-gradient(from 210deg, var(--accent), var(--accent-2), var(--accent));
  box-shadow: 0 0 22px -4px var(--accent);
}

.mark b {
  font-size: 12px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--accent-ink);
}

.brand-text {
  display: flex;
  flex-direction: column;
  min-width: 0;
  line-height: 1.15;
}

.wordmark {
  font-size: 14.5px;
  font-weight: 700;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  color: var(--ink);
}

.tagline {
  font-size: 9.5px;
  font-weight: 550;
  letter-spacing: 0.18em;
  text-transform: uppercase;
  color: var(--ink-muted);
}

.new-chat {
  display: flex;
  align-items: center;
  gap: 9px;
  width: 100%;
  padding: 10px 12px;
  font: inherit;
  font-weight: 550;
  color: var(--ink);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: background 0.18s ease, border-color 0.18s ease, transform 0.18s ease;
}

.new-chat:hover { background: var(--panel-strong); border-color: var(--line-strong); }
.new-chat:active { transform: translateY(1px); }

.new-chat svg, .model-button svg, .icon-button svg, .send svg, .stop svg {
  width: 17px;
  height: 17px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.9;
  stroke-linecap: round;
  stroke-linejoin: round;
}

.chat-search {
  display: flex;
  align-items: center;
  gap: 8px;
  margin: 2px 2px 6px;
  padding: 7px 9px;
  border: 1px solid var(--line);
  border-radius: 9px;
  background: var(--panel);
  color: var(--ink-muted);
}

.chat-search svg {
  flex: none;
  width: 15px;
  height: 15px;
  fill: none;
  stroke: currentColor;
  stroke-width: 1.9;
  stroke-linecap: round;
}

.chat-search input {
  flex: 1;
  min-width: 0;
  border: 0;
  outline: 0;
  background: transparent;
  color: var(--ink);
  font: inherit;
  font-size: 13px;
}

.chat-search input::placeholder { color: var(--ink-muted); }
.chat-search input::-webkit-search-cancel-button { display: none; }

.chat-search kbd {
  flex: none;
  padding: 1px 5px;
  border: 1px solid var(--line-strong);
  border-radius: 5px;
  font-family: var(--mono);
  font-size: 9.5px;
  color: var(--ink-muted);
  opacity: 0.8;
}

.chats {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 2px;
  padding: 4px 2px;
  scrollbar-width: thin;
}

.chat-item {
  position: relative;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 9px 10px;
  border: 0;
  border-radius: 9px;
  background: transparent;
  color: var(--ink-soft);
  font: inherit;
  font-size: 13.5px;
  text-align: left;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.chat-item .chat-label {
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  flex: 1;
}

.chat-item time {
  flex: none;
  margin-left: auto;
  font-size: 10.5px;
  color: var(--ink-muted);
  opacity: 0.75;
}

.chat-item:hover time, .chat-item[aria-current="true"] time { opacity: 0; }

.chats-empty {
  padding: 14px 10px;
  font-size: 12.5px;
  color: var(--ink-muted);
  text-align: center;
}

.chat-item:hover { background: var(--panel); color: var(--ink); }
.chat-item[aria-current="true"] {
  background: linear-gradient(90deg, color-mix(in srgb, var(--accent) 20%, transparent), transparent 85%);
  color: var(--ink);
  box-shadow: inset 2px 0 0 var(--accent);
}

.chat-delete {
  flex: none;
  width: 22px;
  height: 22px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 6px;
  background: transparent;
  color: var(--ink-muted);
  cursor: pointer;
  opacity: 0;
  transition: opacity 0.15s ease, color 0.15s ease;
}

.chat-item:hover .chat-delete, .chat-item[aria-current="true"] .chat-delete { opacity: 1; }
.chat-delete:hover { color: var(--danger); background: var(--panel-strong); }

.sidebar-foot {
  display: flex;
  gap: 8px;
  align-items: center;
  padding-top: 10px;
  border-top: 1px solid var(--line);
}

/* model picker ------------------------------------------------------------- */
.model-picker { position: relative; flex: 1; min-width: 0; }

.model-button {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 8px 10px;
  font: inherit;
  font-size: 12.5px;
  color: var(--ink-soft);
  background: var(--panel);
  border: 1px solid transparent;
  border-radius: 9px;
  cursor: pointer;
  transition: border-color 0.15s ease, background 0.15s ease;
}

.model-button:hover { border-color: var(--line); background: var(--panel-strong); }
.model-name { flex: 1; text-align: left; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }

.model-menu {
  position: absolute;
  bottom: calc(100% + 8px);
  left: 0;
  width: max(260px, 100%);
  padding: 6px;
  background: color-mix(in srgb, var(--bg-soft) 96%, black);
  border: 1px solid var(--line-strong);
  border-radius: 12px;
  box-shadow: var(--shadow);
  max-height: 320px;
  overflow-y: auto;
  z-index: 30;
}

.model-option {
  display: flex;
  align-items: center;
  gap: 8px;
  width: 100%;
  padding: 8px 10px;
  border: 0;
  border-radius: 8px;
  background: transparent;
  color: var(--ink-soft);
  font: inherit;
  font-size: 13px;
  text-align: left;
  cursor: pointer;
}

.model-option:hover { background: var(--panel-strong); color: var(--ink); }
.model-option[aria-selected="true"] { color: var(--ink); background: color-mix(in srgb, var(--accent) 16%, transparent); }
.model-option small { margin-left: auto; font-size: 11px; color: var(--ink-muted); }

/* stage -------------------------------------------------------------------- */
.stage {
  display: flex;
  flex-direction: column;
  min-width: 0;
  min-height: 0;   /* without this the column grows to content and pushes the page */
  height: 100%;
  position: relative;
}

.topbar {
  position: sticky;
  top: 0;
  z-index: 5;
  flex: none;
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 22px;
  border-bottom: 1px solid var(--line);
  background: color-mix(in srgb, var(--bg) 65%, transparent);
  backdrop-filter: blur(14px);
}

.thread-title {
  flex: 1;
  margin: 0;
  font-size: 14px;
  font-weight: 550;
  letter-spacing: 0.01em;
  color: var(--ink-soft);
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
  cursor: text;
  border-radius: 6px;
  padding: 2px 4px;
  margin-left: -4px;
  transition: background 0.15s ease;
}

.thread-title:hover { background: var(--panel); }

.thread-title[contenteditable="true"] {
  background: var(--panel-strong);
  outline: 1px solid var(--accent);
  cursor: text;
}

.status {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 10px;
  font-size: 11.5px;
  color: var(--ink-muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
}

.status span {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  background: var(--ink-muted);
}

.status em { font-style: normal; }

.status[data-state="busy"] { color: var(--accent-2); border-color: color-mix(in srgb, var(--accent-2) 40%, transparent); }
.status[data-state="busy"] span {
  background: var(--accent-2);
  box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent-2) 70%, transparent);
  animation: pulse 1.6s ease-out infinite;
}

.status[data-state="error"] { color: var(--danger); border-color: color-mix(in srgb, var(--danger) 45%, transparent); }
.status[data-state="error"] span { background: var(--danger); }

@keyframes pulse {
  0% { box-shadow: 0 0 0 0 color-mix(in srgb, var(--accent-2) 60%, transparent); }
  100% { box-shadow: 0 0 0 7px transparent; }
}

/* thread ------------------------------------------------------------------- */
.thread {
  flex: 1 1 0;
  min-width: 0;
  min-height: 0;   /* lets the thread scroll instead of stretching the shell */
  overflow-y: auto;
  overflow-x: hidden;
  overscroll-behavior-x: none;
  padding: 34px 22px 12px;
  scrollbar-width: thin;
  scroll-behavior: smooth;
}

.thread > * { max-width: var(--measure); margin-inline: auto; }

.empty {
  display: grid;
  justify-items: center;
  text-align: center;
  gap: 10px;
  padding-top: clamp(20px, 9vh, 90px);
  animation: rise 0.5s ease both;
}

.hero-mark {
  width: 78px;
  height: 78px;
  display: grid;
  place-items: center;
  border-radius: 22px;
  background: conic-gradient(from 205deg, var(--accent), var(--accent-2), #ff86c8, var(--accent));
  box-shadow: 0 20px 55px -18px color-mix(in srgb, var(--accent) 75%, transparent);
  animation: breathe 7s ease-in-out infinite;
}

.hero-mark b {
  font-size: 26px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--accent-ink);
}

.hero-badge {
  margin-top: 4px;
  padding: 3px 10px;
  font-size: 9.5px;
  font-weight: 650;
  letter-spacing: 0.22em;
  text-transform: uppercase;
  color: var(--ink-muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  background: var(--panel);
}

@keyframes breathe {
  0%, 100% { transform: translateY(0) scale(1); }
  50% { transform: translateY(-6px) scale(1.03); }
}

.empty h2 {
  margin: 0;
  font-size: clamp(24px, 3vw, 32px);
  font-weight: 600;
  letter-spacing: -0.02em;
  background: linear-gradient(100deg, var(--ink), color-mix(in srgb, var(--accent) 55%, var(--ink)));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.empty p {
  margin: 0;
  max-width: 34rem;
  color: var(--ink-muted);
  font-size: 13.5px;
}

.suggestions {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-top: 18px;
}

.suggestions button {
  padding: 9px 14px;
  font: inherit;
  font-size: 13px;
  color: var(--ink-soft);
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.18s ease, border-color 0.18s ease, color 0.18s ease, background 0.18s ease;
}

.suggestions button:hover {
  color: var(--ink);
  border-color: color-mix(in srgb, var(--accent) 55%, transparent);
  background: color-mix(in srgb, var(--accent) 12%, transparent);
  transform: translateY(-1px);
}

/* messages ----------------------------------------------------------------- */
.msg {
  display: flex;
  gap: 14px;
  margin-block: 22px;
  animation: rise 0.35s ease both;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: none; }
}

.msg.user { justify-content: flex-end; }

.bubble {
  max-width: 38rem;
  padding: 11px 16px;
  border-radius: 18px 18px 4px 18px;
  background: linear-gradient(140deg, color-mix(in srgb, var(--accent) 26%, transparent), color-mix(in srgb, var(--accent) 12%, transparent));
  border: 1px solid color-mix(in srgb, var(--accent) 34%, transparent);
  color: var(--ink);
  white-space: pre-wrap;
  overflow-wrap: anywhere;
}

.avatar {
  flex: none;
  width: 28px;
  height: 28px;
  display: grid;
  place-items: center;
  margin-top: 2px;
  border-radius: 9px;
  font-size: 9.5px;
  font-weight: 800;
  letter-spacing: 0.01em;
  color: var(--accent-ink);
  background: conic-gradient(from 210deg, var(--accent), var(--accent-2), var(--accent));
  box-shadow: 0 0 18px -6px var(--accent);
}

.body { flex: 1; min-width: 0; }

.byline {
  display: flex;
  align-items: center;
  gap: 8px;
  margin-bottom: 6px;
  font-size: 11.5px;
  color: var(--ink-muted);
}

.byline b { color: var(--ink-soft); font-weight: 550; }

.prose { overflow-wrap: anywhere; min-width: 0; }
.prose img, .prose video, .prose table, .prose iframe { max-width: 100%; }

.prose > :first-child { margin-top: 0; }
.prose > :last-child { margin-bottom: 0; }
.prose p { margin: 0 0 0.85em; }
.prose h1, .prose h2, .prose h3 { margin: 1.3em 0 0.5em; line-height: 1.3; letter-spacing: -0.01em; }
.prose h1 { font-size: 1.35em; }
.prose h2 { font-size: 1.2em; }
.prose h3 { font-size: 1.05em; }
.prose ul, .prose ol { margin: 0 0 0.9em; padding-left: 1.35em; }
.prose li { margin-bottom: 0.3em; }
.prose a { color: var(--accent-2); text-underline-offset: 2px; }
.prose strong { font-weight: 620; color: var(--ink); }
.prose blockquote {
  margin: 0 0 0.9em;
  padding-left: 12px;
  border-left: 2px solid var(--line-strong);
  color: var(--ink-soft);
}
.prose code {
  font-family: var(--mono);
  font-size: 0.87em;
  padding: 0.15em 0.4em;
  border-radius: 5px;
  background: var(--panel-strong);
  border: 1px solid var(--line);
}

.code {
  position: relative;
  margin: 0 0 0.9em;
  border: 1px solid var(--line);
  border-radius: 12px;
  background: color-mix(in srgb, var(--bg-soft) 88%, black);
  overflow: hidden;
}

.code header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 6px 10px;
  font-family: var(--mono);
  font-size: 10.5px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-muted);
  border-bottom: 1px solid var(--line);
}

.code button {
  font: inherit;
  font-size: 10.5px;
  letter-spacing: 0.06em;
  color: var(--ink-muted);
  background: transparent;
  border: 0;
  cursor: pointer;
  text-transform: uppercase;
}

.code button:hover { color: var(--accent-2); }

.code pre {
  margin: 0;
  max-width: 100%;
  padding: 12px 14px;
  overflow-x: auto;
  font-family: var(--mono);
  font-size: 12.8px;
  line-height: 1.6;
}

.code code { background: none; border: 0; padding: 0; font-size: inherit; }

/* reasoning + tool trace */
.trace { margin: 4px 0 10px; }

.trace summary {
  display: inline-flex;
  align-items: center;
  gap: 7px;
  padding: 4px 9px;
  font-size: 11.5px;
  color: var(--ink-muted);
  border: 1px dashed var(--line-strong);
  border-radius: 999px;
  cursor: pointer;
  list-style: none;
}

.trace summary::-webkit-details-marker { display: none; }
.trace summary:hover { color: var(--ink-soft); border-color: var(--accent); }

.trace[open] summary { color: var(--accent-2); border-color: color-mix(in srgb, var(--accent-2) 45%, transparent); }

.trace .trace-body {
  margin-top: 8px;
  padding: 10px 12px;
  font-family: var(--mono);
  font-size: 11.8px;
  line-height: 1.6;
  color: var(--ink-muted);
  white-space: pre-wrap;
  border-left: 2px solid var(--line-strong);
  max-height: 240px;
  overflow-y: auto;
}

.tool-chip {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin: 0 6px 6px 0;
  padding: 3px 8px;
  font-family: var(--mono);
  font-size: 11px;
  color: var(--accent-2);
  background: color-mix(in srgb, var(--accent-2) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--accent-2) 28%, transparent);
  border-radius: 6px;
}

.msg-actions {
  display: flex;
  gap: 4px;
  margin-top: 8px;
  opacity: 0;
  transition: opacity 0.15s ease;
}

.msg:hover .msg-actions { opacity: 1; }

.msg-actions button {
  font: inherit;
  font-size: 11.5px;
  padding: 3px 8px;
  color: var(--ink-muted);
  background: transparent;
  border: 1px solid transparent;
  border-radius: 6px;
  cursor: pointer;
}

.msg-actions button:hover { color: var(--ink); border-color: var(--line); background: var(--panel); }

.usage {
  margin-top: 6px;
  font-family: var(--mono);
  font-size: 10.5px;
  color: var(--ink-muted);
  opacity: 0.75;
}

.dots { display: inline-flex; gap: 4px; padding: 6px 0; }
.dots i {
  width: 5px;
  height: 5px;
  border-radius: 50%;
  background: var(--accent-2);
  animation: blink 1.4s infinite ease-in-out;
}
.dots i:nth-child(2) { animation-delay: 0.18s; }
.dots i:nth-child(3) { animation-delay: 0.36s; }

@keyframes blink {
  0%, 80%, 100% { opacity: 0.25; transform: translateY(0); }
  40% { opacity: 1; transform: translateY(-2px); }
}

.error-note {
  margin-top: 8px;
  padding: 9px 12px;
  font-size: 12.5px;
  color: var(--danger);
  background: color-mix(in srgb, var(--danger) 10%, transparent);
  border: 1px solid color-mix(in srgb, var(--danger) 35%, transparent);
  border-radius: 9px;
}

/* composer ----------------------------------------------------------------- */
.jump {
  position: absolute;
  right: 26px;
  bottom: 104px;
  z-index: 6;
  width: 34px;
  height: 34px;
  display: grid;
  place-items: center;
  border: 1px solid var(--line-strong);
  border-radius: 50%;
  background: var(--panel-strong);
  color: var(--ink-soft);
  box-shadow: var(--shadow);
  cursor: pointer;
  animation: rise 0.18s ease both;
}

.jump:hover { color: var(--ink); border-color: var(--accent); }
.jump svg { width: 16px; height: 16px; fill: none; stroke: currentColor; stroke-width: 2; stroke-linecap: round; stroke-linejoin: round; }

.composer {
  flex: none;
  padding: 12px 22px 18px;
  background: linear-gradient(to top, var(--bg) 55%, transparent);
}

.composer > * { max-width: var(--measure); margin-inline: auto; }

.field {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  padding: 8px 8px 8px 14px;
  background: color-mix(in srgb, var(--bg-soft) 88%, transparent);
  border: 1px solid var(--line);
  border-radius: 18px;
  box-shadow: var(--shadow);
  transition: border-color 0.2s ease, box-shadow 0.2s ease;
}

.field:focus-within {
  border-color: color-mix(in srgb, var(--accent) 60%, transparent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 14%, transparent), var(--shadow);
}

#input {
  flex: 1;
  max-height: 220px;
  padding: 7px 0;
  font: inherit;
  color: var(--ink);
  background: transparent;
  border: 0;
  outline: none;
  resize: none;
  line-height: 1.55;
}

#input::placeholder { color: var(--ink-muted); }

.send, .stop {
  flex: none;
  width: 36px;
  height: 36px;
  display: grid;
  place-items: center;
  border: 0;
  border-radius: 11px;
  cursor: pointer;
  transition: transform 0.15s ease, filter 0.15s ease, opacity 0.15s ease;
}

.send {
  color: var(--accent-ink);
  background: linear-gradient(140deg, var(--accent), color-mix(in srgb, var(--accent-2) 60%, var(--accent)));
  box-shadow: 0 8px 22px -10px var(--accent);
}

.send:hover { filter: brightness(1.08); transform: translateY(-1px); }
.send:disabled { opacity: 0.4; cursor: not-allowed; transform: none; filter: none; }

.stop { color: var(--danger); background: color-mix(in srgb, var(--danger) 14%, transparent); border: 1px solid color-mix(in srgb, var(--danger) 40%, transparent); }

.composer-hint {
  margin: 8px 0 0;
  text-align: center;
  font-size: 11px;
  color: var(--ink-muted);
}

kbd {
  padding: 1px 5px;
  font-family: var(--mono);
  font-size: 10px;
  border: 1px solid var(--line-strong);
  border-radius: 4px;
  background: var(--panel);
}

/* utilities ---------------------------------------------------------------- */
.ghost {
  background: transparent;
  border: 1px solid var(--line);
  color: var(--ink-soft);
}

.ghost:hover { color: var(--ink); border-color: var(--line-strong); background: var(--panel); }

.icon-button {
  flex: none;
  width: 38px;
  height: 38px;
  display: grid;
  place-items: center;
  border-radius: 10px;
  cursor: pointer;
  transition: background 0.15s ease, color 0.15s ease;
}

.only-mobile { display: none; }

.toast {
  position: fixed;
  left: 50%;
  bottom: 26px;
  transform: translateX(-50%);
  max-width: min(90vw, 30rem);
  padding: 10px 16px;
  font-size: 13px;
  color: var(--ink);
  background: color-mix(in srgb, var(--bg-soft) 92%, black);
  border: 1px solid color-mix(in srgb, var(--danger) 45%, transparent);
  border-radius: 10px;
  box-shadow: var(--shadow);
  z-index: 50;
}

/* scrollbars --------------------------------------------------------------- */
/* Kill the native light track + arrow buttons that show up in dark mode. */
::-webkit-scrollbar { width: 9px; height: 9px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb {
  background: color-mix(in srgb, var(--ink-muted) 45%, transparent);
  border-radius: 999px;
  border: 2px solid transparent;
  background-clip: padding-box;
}
::-webkit-scrollbar-thumb:hover { background: color-mix(in srgb, var(--ink-muted) 75%, transparent); background-clip: padding-box; }
::-webkit-scrollbar-button { display: none; width: 0; height: 0; }
::-webkit-scrollbar-corner { background: transparent; }

html { scrollbar-width: thin; scrollbar-color: color-mix(in srgb, var(--ink-muted) 45%, transparent) transparent; }

#input { scrollbar-width: thin; scrollbar-color: color-mix(in srgb, var(--ink-muted) 45%, transparent) transparent; }

.scrim {
  position: fixed;
  inset: 0;
  z-index: 35;
  background: rgba(4, 5, 9, 0.55);
  backdrop-filter: blur(2px);
  animation: fade 0.2s ease both;
}

@keyframes fade { from { opacity: 0; } to { opacity: 1; } }

/* responsive --------------------------------------------------------------- */
@media (max-width: 860px) {
  .app { grid-template-columns: 1fr; }

  .sidebar {
    position: fixed;
    inset: 0 auto 0 0;
    width: min(84vw, 300px);
    z-index: 40;
    transform: translateX(-102%);
    transition: transform 0.28s cubic-bezier(0.4, 0, 0.2, 1);
    box-shadow: var(--shadow);
  }

  .sidebar.open { transform: none; }
  .only-mobile { display: grid; }
  .thread { padding: 24px 16px 8px; }
  .composer { padding: 10px 14px 14px; }
  .topbar { padding: 12px 14px; }
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after { animation: none !important; transition: none !important; }
  .thread { scroll-behavior: auto; }
}