/* ================= THEME TOKENS + TYPE SYSTEM ================= */
:root {
  --accent: #2f6fed;
  --accent-strong: #1d54c9;
  --accent-glow: rgba(47, 111, 237, 0.18);
  --r-l: 32px;
  --r-m: 20px;
  --r-s: 12px;
  --ease: cubic-bezier(0.25, 1, 0.5, 1);
  --spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --drift: cubic-bezier(0.45, 0.05, 0.55, 0.95);

  --font-body: 'Sora', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-display: 'Sora', var(--font-body);
  --font-input: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  --font-bubble: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, 'Helvetica Neue', Arial, sans-serif;

  --fs-chat: clamp(15px, 14px + 0.25vw, 16.5px);
  --lh-chat: 1.75;
  --measure: 72ch;
  --ls-display: -0.03em;

  --column: 820px;
  --composer-initial: 640px;
  --gutter: clamp(16px, 3vw, 24px);
}

/* LIGHT THEME */
[data-theme="light"] {
  --bg: #f0f2f8;
  --text: #070c1c;
  --muted: #252d44;
  --panel: rgba(255, 255, 255, 0.66);
  --panel-solid: #ffffff;
  --input-bg: #ffffff;
  --user-bubble: #ffffff;
  --line: rgba(10, 15, 35, 0.16);
  --card-border: rgba(10, 15, 35, 0.22);
  --hover: rgba(10, 15, 35, 0.10);
  --input-border: rgba(10, 15, 35, 0.20);
  --grid-color: rgba(10, 15, 35, 0.08);
  --sh-1: 0 1px 2px rgba(10, 15, 35, 0.10);
  --sh-2: 0 1px 2px rgba(10, 15, 35, 0.10), 0 2px 6px -2px rgba(10, 15, 35, 0.14);
  --sh-3: 0 1px 2px rgba(10, 15, 35, 0.10), 0 12px 32px -16px rgba(10, 15, 35, 0.22);
  --sh-4: 0 8px 24px -8px rgba(10, 15, 35, 0.26), 0 2px 6px -2px rgba(10, 15, 35, 0.14);
  --ring: 0 0 0 0 rgba(47, 111, 237, 0);
  --ring-on: 0 0 0 3px rgba(47, 111, 237, 0.20);
  --composer-sheen: none;
  color-scheme: light;
}
[data-theme="light"] body {
  background:
    radial-gradient(1200px 700px at 50% -10%, rgba(200, 190, 245, 0.55), transparent 65%),
    radial-gradient(900px 600px at 15% 30%, rgba(220, 200, 215, 0.40), transparent 60%),
    radial-gradient(1000px 700px at 85% 25%, rgba(190, 210, 245, 0.35), transparent 60%),
    linear-gradient(180deg, #e8eef8 0%, #eef2fa 45%, #f4f6fb 100%);
}

/* DARK THEME */
[data-theme="dark"] {
  --bg: #060b16;
  --grid-color: rgba(255, 255, 255, 0.02);
  --panel: rgba(13, 20, 36, 0.7);
  --panel-solid: #0d1424;
  --text: #f3f6fc;
  --muted: #8ea0bd;
  --line: rgba(255, 255, 255, 0.05);
  --card-border: rgba(255, 255, 255, 0.09);
  --hover: rgba(255, 255, 255, 0.045);
  --input-bg: rgba(13, 20, 36, 0.78);
  --input-border: rgba(255, 255, 255, 0.08);
  --user-bubble: #16233d;
  --composer-sheen: linear-gradient(180deg, rgba(255,255,255,0.04) 0%, rgba(255,255,255,0) 100%);
  --sh-1: 0 1px 2px rgba(0, 0, 0, 0.3);
  --sh-2: 0 1px 2px rgba(0, 0, 0, 0.32), 0 1px 3px rgba(0, 0, 0, 0.22);
  --sh-3: 0 2px 6px -2px rgba(0, 0, 0, 0.4);
  --sh-4: 0 6px 14px -8px rgba(0, 0, 0, 0.55);
  --ring: 0 0 0 0 rgba(90, 145, 255, 0);
  --ring-on: 0 0 0 3px rgba(90, 145, 255, 0.18);
  color-scheme: dark;
}
@media (prefers-color-scheme: dark) {
  [data-theme="system"] {
    --bg: #060b16; --grid-color: rgba(255, 255, 255, 0.02);
    --panel: rgba(13, 20, 36, 0.7); --panel-solid: #0d1424;
    --text: #f3f6fc; --muted: #8ea0bd; --line: rgba(255, 255, 255, 0.05);
    --card-border: rgba(255, 255, 255, 0.09); --hover: rgba(255, 255, 255, 0.045);
    --input-bg: rgba(13, 20, 36, 0.78); --input-border: rgba(255, 255, 255, 0.08);
    --user-bubble: #16233d;
    --composer-sheen: linear-gradient(180deg, rgba(255,255,255,0.04) 0%, rgba(255,255,255,0) 100%);
    --sh-1: 0 1px 2px rgba(0, 0, 0, 0.3);
    --sh-2: 0 1px 2px rgba(0, 0, 0, 0.32), 0 1px 3px rgba(0, 0, 0, 0.22);
    --sh-3: 0 2px 6px -2px rgba(0, 0, 0, 0.4);
    --sh-4: 0 6px 14px -8px rgba(0, 0, 0, 0.55);
    --ring: 0 0 0 0 rgba(90, 145, 255, 0);
    --ring-on: 0 0 0 3px rgba(90, 145, 255, 0.18);
    color-scheme: dark;
  }
}
@media (prefers-color-scheme: light) {
  [data-theme="system"] {
    --bg: #f0f2f8; --grid-color: rgba(10, 15, 35, 0.08);
    --panel: rgba(255, 255, 255, 0.66); --panel-solid: #ffffff;
    --text: #070c1c; --muted: #252d44; --line: rgba(10, 15, 35, 0.16);
    --card-border: rgba(10, 15, 35, 0.22); --hover: rgba(10, 15, 35, 0.10);
    --input-bg: #ffffff; --input-border: rgba(10, 15, 35, 0.20);
    --user-bubble: #ffffff;
    --composer-sheen: none;
    --sh-1: 0 1px 2px rgba(10, 15, 35, 0.10);
    --sh-2: 0 1px 2px rgba(10, 15, 35, 0.10), 0 2px 6px -2px rgba(10, 15, 35, 0.14);
    --sh-3: 0 1px 2px rgba(10, 15, 35, 0.10), 0 12px 32px -16px rgba(10, 15, 35, 0.22);
    --sh-4: 0 8px 24px -8px rgba(10, 15, 35, 0.26), 0 2px 6px -2px rgba(10, 15, 35, 0.14);
    --ring: 0 0 0 0 rgba(47, 111, 237, 0);
    --ring-on: 0 0 0 3px rgba(47, 111, 237, 0.20);
    color-scheme: light;
  }
}
@media (prefers-color-scheme: light) {
  [data-theme="system"] body {
    background:
      radial-gradient(1200px 700px at 50% -10%, rgba(200, 190, 245, 0.55), transparent 65%),
      radial-gradient(900px 600px at 15% 30%, rgba(220, 200, 215, 0.40), transparent 60%),
      radial-gradient(1000px 700px at 85% 25%, rgba(190, 210, 245, 0.35), transparent 60%),
      linear-gradient(180deg, #e8eef8 0%, #eef2fa 45%, #f4f6fb 100%);
  }
}

/* ================= BASE ================= */
*{box-sizing:border-box;margin:0;padding:0;}
html,body{height:100%;}
body{
  font-family:var(--font-body);
  font-kerning:normal;
  text-rendering:optimizeLegibility;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
  color:var(--text);
  height:100dvh; overflow:hidden;
  overscroll-behavior: none;
  transition: background-color .6s ease, color .4s ease;
}
::selection{background:color-mix(in srgb, var(--accent) 25%, transparent);}
button{font-family:inherit; user-select:none; border:none; background:none; cursor:pointer; color:inherit;}

/* ---------- Main ---------- */
main{flex:1; min-width:0; display:flex; flex-direction:column; position:relative; height:100dvh; overflow:hidden;}

/* ---------- Content ---------- */
.content{
  position: relative; z-index: 5; width: 100%;
  flex: 1 1 auto; min-height: 0;
  overflow-y: auto; scrollbar-width: none;
  display: flex; flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  padding-top: clamp(100px, 22vh, 220px);
  padding-bottom: 0;
  transition: padding-top 0.6s var(--ease);
}
.content::-webkit-scrollbar { display: none; }

.content.session-active {
  padding-top: 0;
}

h1{
  font-family: var(--font-display);
  font-size: clamp(32px, 4.4vw, 56px);
  line-height: 1.12; font-weight: 300;
  letter-spacing: var(--ls-display); color: var(--text);
  text-wrap: balance; text-align: center;
  width: 100%;
  max-width: calc(var(--column) + var(--gutter) * 2);
  padding: 0 var(--gutter);
  transition: opacity 0.5s ease, transform 0.5s ease, margin 0.5s ease;
  margin-bottom: 0;
}
.greeting-sub {
  color: var(--muted); display: block;
  font-size: clamp(15px, 1.8vw, 18px);
  font-weight: 400;
  margin: 14px 0 clamp(24px, 3.5vh, 40px);
  letter-spacing: -0.01em;
}
.greeting-sub[hidden] { display: none; }
h1.hidden { opacity: 0; transform: translateY(-30px); margin: 0; height: 0; overflow: hidden; pointer-events: none; }

/* ---------- Chat ---------- */
.chat {
  display: flex; flex-direction: column;
  gap: clamp(20px, 3vw, 32px);
  margin-bottom: clamp(20px, 3vw, 32px);
  width: 100%;
  max-width: calc(var(--column) + var(--gutter) * 2);
  padding: 0 var(--gutter);
}
.chat:empty {
  display: none;
  margin: 0;
}

.content.session-active .chat {
  display: flex;
  flex: 1 0 auto;
  padding-top: clamp(28px, 5vh, 52px);
}
/* ---------- MESSAGE BASE (shared typography) ---------- */
.message {
  font-family: var(--font-bubble);
  font-size: var(--fs-chat);
  font-weight: 500;
  line-height: 1.55;
  letter-spacing: -0.011em;
  font-kerning: normal;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1, "cv05" 1, "ss03" 1;
  font-optical-sizing: auto;
  word-wrap: break-word;
  position: relative;
  animation: msgIn 0.4s var(--ease) both;
}
@keyframes msgIn { from { opacity: 0; transform: translateY(12px); } to { opacity: 1; transform: none; } }

/* ---------- USER BUBBLE ---------- */
.message.user {
  align-self: flex-end;
  background: var(--user-bubble);
  color: var(--text);
  border-radius: clamp(16px, 3vw, 22px);
  padding: clamp(10px, 2vw, 14px) clamp(16px, 3vw, 22px);
  max-width: clamp(70%, 80vw, 80%);
  text-wrap: pretty;
  white-space: pre-wrap;
  box-shadow: var(--sh-2), 0 0 0 1px var(--card-border);
}

/* ---------- AI MESSAGE (matches bubble typography, no bubble chrome) ---------- */
.message.ai {
  align-self: flex-start;
  background: transparent;
  color: var(--text);
  border: none;
  padding: 0;
  max-width: 100%;
  width: 100%;
  text-wrap: pretty;
}
.message.ai.loading { display: flex; align-items: center; gap: 12px; }

.answer p { margin: 0 0 1em; max-width: var(--measure); text-wrap: pretty; }
.answer p:last-child { margin-bottom: 0; }
.answer .stream-active { max-width: var(--measure); white-space: pre-wrap; }

.stream-caret{ display:inline-block; width:8px; height:1.05em; background:var(--accent); border-radius:2px; margin-left:4px; vertical-align:text-bottom; animation: caretBlink .8s steps(2) infinite; }
@keyframes caretBlink{ 50%{ opacity:0; } }
.ai-actions { display: flex; gap: 6px; margin-top: 16px; opacity: 1; }
.action-btn { width: 32px; height: 32px; border-radius: 8px; display: grid; place-items: center; color: var(--muted); transition: background 0.2s var(--ease), color 0.2s var(--ease); }
.action-btn:hover { background: var(--hover); color: var(--text); }
.action-btn svg { width: 16px; height: 16px; stroke: currentColor; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }

.think-spinner { width: 20px; height: 20px; border-radius: 50%; border: 2.5px solid var(--card-border); border-top-color: var(--accent); animation: spinChrome 1.2s cubic-bezier(0.5, 0, 0.5, 1) infinite; }
.think-text { font-size: 14px; font-weight: 500; color: var(--muted); letter-spacing: 0.01em; }
@keyframes spinChrome { 0% { transform: rotate(0deg); } 100% { transform: rotate(360deg); } }

/* ---------- Markdown content (.answer) ---------- */
.answer :is(h1,h2,h3,h4,h5,h6){ margin: 1.3em 0 0.5em; max-width: var(--measure); font-weight: 700; letter-spacing: -0.01em; }
.answer :is(h1,h2,h3,h4,h5,h6):first-child { margin-top: 0; }
.answer h1{ font-size: 1.45em; } .answer h2{ font-size: 1.28em; } .answer h3{ font-size: 1.14em; }
.answer h4{ font-size: 1.05em; } .answer h5{ font-size: 1em; } .answer h6{ font-size: .95em; }
.answer a{ color: var(--accent); text-decoration: underline; text-underline-offset: 2px; transition: color .2s ease; }
.answer a:hover{ color: var(--accent-strong); }
.answer strong{ font-weight: 700; }
.answer em{ font-style: italic; }
.answer del{ opacity: .6; }
.answer code{ font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, 'Cascadia Code', monospace; font-size: .88em; }
.answer :not(pre) > code{ background: var(--hover); border: 1px solid var(--card-border); border-radius: 6px; padding: .08em .32em; }
.answer .md-pre{ margin: .7em 0; max-width: var(--measure); padding: 14px 18px; background: var(--input-bg); border: 1px solid var(--card-border); border-radius: var(--r-s); overflow-x: auto; box-shadow: var(--sh-1); position: relative; }
.answer .md-pre code{ font-size: .86em; line-height: 1.6; white-space: pre; }
.answer .md-pre .code-copy{ position: absolute; top: 10px; right: 10px; width: 30px; height: 30px; border-radius: 8px; display: grid; place-items: center; color: var(--muted); background: var(--panel-solid); border: 1px solid var(--card-border); opacity: 0; transition: opacity .2s var(--ease), color .2s var(--ease), background .2s var(--ease); z-index: 2; }
.answer .md-pre:hover .code-copy{ opacity: 1; }
.code-copy:hover{ color: var(--text); background: var(--hover); }
.code-copy svg{ width: 15px; height: 15px; stroke: currentColor; fill: none; stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; }
.answer .md-quote{ margin: .7em 0; max-width: var(--measure); padding: .35em 1em .35em 1.1em; border-left: 3px solid color-mix(in srgb, var(--accent) 55%, transparent); background: color-mix(in srgb, var(--muted) 8%, transparent); border-radius: 0 10px 10px 0; color: var(--muted); }
.answer .md-quote p{ margin: .4em 0; }
.answer .md-quote :is(h1,h2,h3,h4,h5,h6){ margin: .6em 0 .3em; color: var(--text); }
.answer .md-hr{ border: 0; height: 1px; background: var(--line); margin: 1.1em 0; max-width: var(--measure); }
.answer .md-list{ margin: .5em 0; max-width: var(--measure); }
.answer ul, .answer ol{ padding-left: 16px; }
.answer ul ul, .answer ol ul, .answer ul ol, .answer ol ol{ margin-top: .3em; }
.answer li{ margin: .3em 0; }
.answer li::marker{ color: var(--muted); }
.answer li.md-task{ list-style: none; }
.answer li.md-task input{ margin: .18em .1em 0 0; accent-color: var(--accent); width: 15px; height: 15px; }
.answer li.md-task.checked > span{ color: var(--muted); text-decoration: line-through; }
.answer .md-table-wrap{ margin: .8em 0; overflow-x: auto; border: 1px solid var(--card-border); border-radius: var(--r-s); background: color-mix(in srgb, var(--panel-solid) 55%, transparent); box-shadow: var(--sh-1); }
.answer .md-table-wrap table{ border-collapse: collapse; width: 100%; font-size: .94em; }
.answer .md-table-wrap th, .answer .md-table-wrap td{ padding: 8px 14px; text-align: left; border-bottom: 1px solid var(--line); max-width: 42ch; vertical-align: top; }
.answer .md-table-wrap th{ font-weight: 600; background: var(--hover); }
.answer .md-table-wrap tr:last-child td{ border-bottom: 0; }
.answer .align-center{ text-align: center; }
.answer .align-right{ text-align: right; }

/* ---------- Composer ---------- */
.composer-wrap {
  position: relative;
  margin-top: 0;
  width: 100%;
  max-width: calc(var(--composer-initial) + var(--gutter) * 2);
  padding: 0 var(--gutter) clamp(24px, 5vh, 44px);
  flex-shrink: 0;
  transition: max-width 0.6s var(--ease);
}

.content.session-active .composer-wrap {
  position: sticky;
  bottom: 0;
  margin-top: auto;
  max-width: calc(var(--column) + var(--gutter) * 2);
  padding: 12px var(--gutter) clamp(16px, 3vh, 24px);
  background: linear-gradient(
    to bottom,
    transparent 0%,
    color-mix(in srgb, var(--bg) 80%, transparent) 30%,
    var(--bg) 70%,
    var(--bg) 100%
  );
  z-index: 10;
}

.composer {
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 32px;
  padding: 24px 28px 18px;
  backdrop-filter: blur(20px) saturate(140%);
  -webkit-backdrop-filter: blur(20px) saturate(140%);
  transition: border-color 0.25s var(--ease), background 0.3s ease;
  display: flex; flex-direction: column;
  position: relative;
  overflow: visible;
}
.composer::before { content: ''; position: absolute; inset: 0; border-radius: inherit; background: var(--composer-sheen); pointer-events: none; z-index: 0; }
.composer:focus-within { border-color: color-mix(in srgb, var(--accent) 42%, transparent); }
[data-theme="light"] .composer { backdrop-filter: none; -webkit-backdrop-filter: none; }
[data-theme="light"] .composer:focus-within { border-color: rgba(47, 111, 237, 0.34); }
@media (prefers-color-scheme: light) {
  [data-theme="system"] .composer { backdrop-filter: none; -webkit-backdrop-filter: none; }
  [data-theme="system"] .composer:focus-within { border-color: rgba(47, 111, 237, 0.34); }
}

.composer textarea {
  display: block; width: 100%; resize: none; border: none; background: transparent;
  font-family: var(--font-input);
  font-size: clamp(16px, 15.5px + 0.2vw, 17.5px);
  font-weight: 400;
  line-height: 1.6;
  letter-spacing: -0.011em;
  font-kerning: normal;
  font-feature-settings: "kern" 1, "liga" 1, "calt" 1, "ss01" 1;
  max-height: 200px;
  padding: 2px 4px 4px;
  color: var(--text); outline: none; caret-color: var(--accent);
  position: relative; z-index: 1;
}
.composer textarea::placeholder {
  color: var(--muted); opacity: 0.62; font-weight: 400; letter-spacing: -0.008em;
}

.composer-bar { display: flex; align-items: center; justify-content: space-between; padding-top: clamp(12px, 2vw, 16px); margin-top: clamp(8px, 1.5vw, 12px); position: relative; z-index: 1; }
.cb-left, .cb-right { display: flex; align-items: center; gap: clamp(6px, 1vw, 8px); }

.model-dd{ position: relative; }
.model-trigger{ display:flex; align-items:center; gap:clamp(6px, 1vw, 8px); padding:clamp(6px, 1vw, 8px) clamp(10px, 1.5vw, 14px); border-radius: clamp(12px, 2vw, 16px); border: 1px solid var(--card-border); background: var(--panel-solid); color:var(--text); font-size:clamp(11px, 1.5vw, 13px); font-weight:600; letter-spacing:0.02em; transition: background 0.2s var(--ease), border-color 0.2s var(--ease); box-shadow: var(--sh-1); }
.model-trigger:hover { background: var(--hover); border-color: color-mix(in srgb, var(--muted) 45%, transparent); }
.m-icon { width: 16px; height: 16px; color: var(--accent); flex-shrink: 0; display:grid; place-items:center; }
.m-icon svg { width:16px; height:16px; }
.model-trigger .chev{ width:14px; height:14px; color:var(--muted); transition: none; }
.model-dd.open .model-trigger .chev{ transform: rotate(180deg); }
.model-panel{ position:absolute; bottom:calc(100% + clamp(12px, 2vw, 16px)); left:0; width: clamp(240px, 30vw, 300px); background: var(--panel-solid); border:1px solid var(--card-border); border-radius: clamp(16px, 3vw, 24px); padding: clamp(8px, 1.5vw, 10px); box-shadow: var(--sh-4); opacity:0; transform: translateY(10px) scale(0.96); transform-origin: bottom left; pointer-events:none; transition: opacity 0.25s var(--ease), transform 0.25s var(--spring); z-index: 9999; }
.model-dd.open .model-panel{ opacity:1; transform: translateY(0) scale(1); pointer-events:auto; }
.model-item{ display:flex; align-items:center; gap:12px; width:100%; padding:12px 14px; border-radius: 16px; text-align:left; transition: background 0.2s; }
.model-item:hover{ background: var(--hover); }
.model-item.selected{ background: color-mix(in srgb, var(--accent) 10%, transparent); }
.mi-icon { flex:0 0 20px; width:20px; height:20px; color: var(--muted); stroke-width: 1.8; stroke-linecap: round; stroke-linejoin: round; transition: color 0.2s; }
.model-item:hover .mi-icon, .model-item.selected .mi-icon { color: var(--accent); }
.mi-txt{ display:flex; flex-direction:column; gap:2px; min-width:0; }
.mi-code{ font-size:13.5px; font-weight:700; color:var(--text); letter-spacing:0.02em; }
.mi-desc{ font-size:11.5px; color:var(--muted); font-weight:500; white-space:nowrap; overflow:hidden; text-overflow:ellipsis; }
.mi-check{ margin-left:auto; width:16px; height:16px; color:var(--accent); opacity:0; transform:scale(0.6); transition: opacity 0.2s, transform 0.3s var(--spring); flex:0 0 16px; }
.model-item.selected .mi-check{ opacity:1; transform:scale(1); }

.send { width: 42px; height: 42px; border-radius: 50%; display: grid; place-items: center; background: var(--hover); color: var(--muted); transition: background 0.2s var(--ease), color 0.2s var(--ease); border: 1px solid transparent; }
.send svg { width: 20px; height: 20px; stroke: currentColor; fill: none; stroke-width: 2.5; stroke-linecap: round; stroke-linejoin: round; }
.send.ready { background: var(--accent); color: #fff; box-shadow: var(--sh-2); border-color: var(--accent); }
.send.ready:hover { background: var(--accent-strong); }
.send:disabled { opacity: 0.5; cursor: not-allowed; }

.model-trigger:focus-visible,
.send:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }

.toast{ position: fixed; left: 50%; bottom: 40px; transform: translate(-50%, 20px); z-index: 200; background: var(--panel-solid); border: 1px solid var(--card-border); color: var(--text); font-size: 14px; font-weight: 500; padding: 14px 24px; border-radius: 16px; opacity: 0; pointer-events: none; transition: opacity 0.3s var(--ease), transform 0.3s var(--spring); box-shadow: var(--sh-4); max-width: min(90vw, 480px); text-align: center; }
.toast.show{ opacity: 1; transform: translate(-50%, 0); }

@media (max-width: 900px){ .content { padding-top: clamp(72px, 16vh, 160px); } }
@media (min-width: 1600px){
  :root{ --fs-chat: 17px; --measure: 75ch; --column: 960px; --composer-initial: 720px; }
}
@media (max-width: 600px){
  :root { --gutter: clamp(12px, 3vw, 16px); --composer-initial: 480px; }
  .model-trigger{ font-size: clamp(10px, 2vw, 11.5px); padding: clamp(4px, 1vw, 6px) clamp(8px, 1.5vw, 10px); }
  .model-panel{ width: clamp(200px, 60vw, 260px); }
  .message.user{ max-width: clamp(85%, 90vw, 90%); }
  .composer { padding: clamp(14px, 3vw, 20px) clamp(14px, 3vw, 20px) clamp(10px, 2vw, 14px); border-radius: clamp(20px, 5vw, 28px); }
  .send { width: clamp(34px, 7vw, 40px); height: clamp(34px, 7vw, 40px); }
  .content.session-active .chat { padding-top: clamp(16px, 3vh, 28px); }
}
@media (hover: none) and (pointer: coarse) { .answer .md-pre .code-copy { opacity: 1; } }
@media (prefers-reduced-motion: reduce){
  *, *::before, *::after { animation-duration: 0.01ms !important; animation-iteration-count: 1 !important; transition-duration: 0.01ms !important; }
}

/* ---------- Brand polish ---------- */
body {
  background: var(--bg);
}
h1 {
  font-weight: 500;
  letter-spacing: -0.055em;
}
.greeting-sub {
  color: var(--muted);
  letter-spacing: -0.02em;
  max-width: 42ch;
}
.composer {
  border-color: var(--input-border);
  box-shadow: var(--sh-1);
}
.composer:focus-within {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px color-mix(in srgb, var(--accent) 14%, transparent);
}
.model-trigger {
  backdrop-filter: none;
  -webkit-backdrop-filter: none;
  transition: background 0.2s var(--ease), border-color 0.2s var(--ease), transform 0.2s var(--ease);
}
.model-trigger:hover {
  transform: none;
}
.message.user { border: 1px solid var(--card-border); }

/* ---------- LOW-POWER / LEGACY-DEVICE MODE ---------- */
/* The profile is selected before the stylesheet is applied in index.html. */
html[data-performance="lite"] body {
  background: var(--bg) !important;
  text-rendering: auto;
}
html[data-performance="lite"] .composer,
html[data-performance="lite"] .model-panel,
html[data-performance="lite"] .toast {
  backdrop-filter: none !important;
  -webkit-backdrop-filter: none !important;
}
html[data-performance="lite"] .message {
  contain: layout style;
  content-visibility: auto;
  contain-intrinsic-size: 80px;
  animation: none !important;
}
html[data-performance="lite"] .message.loading {
  content-visibility: visible;
}
html[data-performance="lite"] .stream-caret,
html[data-performance="lite"] .think-spinner {
  animation: none !important;
}
html[data-performance="lite"] .think-spinner {
  border-color: var(--accent);
  opacity: 0.7;
}
html[data-performance="lite"] .composer textarea {
  font-optical-sizing: none;
  font-feature-settings: normal;
}
@media (prefers-reduced-motion: reduce) {
  .composer,
  .model-panel,
  .toast { backdrop-filter: none; -webkit-backdrop-filter: none; }
}