@font-face {
  font-family: "OpenAI Sans";
  font-style: normal;
  font-weight: 400;
  font-display: swap;
  src: url("https://cdn.openai.com/common/fonts/openai-sans/v2/OpenAISans-Regular.woff2") format("woff2");
}

@font-face {
  font-family: "OpenAI Sans";
  font-style: normal;
  font-weight: 500;
  font-display: swap;
  src: url("https://cdn.openai.com/common/fonts/openai-sans/v2/OpenAISans-Medium.woff2") format("woff2");
}

@font-face {
  font-family: "OpenAI Sans";
  font-style: normal;
  font-weight: 600;
  font-display: swap;
  src: url("https://cdn.openai.com/common/fonts/openai-sans/v2/OpenAISans-Semibold.woff2") format("woff2");
}

:root {
  color-scheme: light;
  --spacing: 0.25rem;
  --white: #fff;
  --black: #000;
  --gray-50: #f9f9f9;
  --gray-100: #ececec;
  --gray-200: #e3e3e3;
  --gray-300: #cdcdcd;
  --gray-400: #b4b4b4;
  --gray-500: #9b9b9b;
  --gray-600: #676767;
  --gray-700: #424242;
  --gray-750: #2f2f2f;
  --gray-800: #212121;
  --gray-900: #171717;
  --gray-950: #0d0d0d;
  --main-surface-background: #fffffff2;
  --message-surface: #e9e9e980;
  --composer-surface: var(--message-surface);
  --composer-blue-bg: #daeeff;
  --composer-blue-hover: #bddcf4;
  --composer-blue-hover-tint: #0084ff24;
  --composer-surface-primary: var(--main-surface-primary);
  --dot-color: var(--black);
  --text-primary: var(--gray-950);
  --text-primary-inverse: var(--gray-100);
  --text-secondary: #0009;
  --text-tertiary: #0000004a;
  --text-quaternary: #00000030;
  --text-placeholder: #000000b3;
  --text-error: #f93a37;
  --border-xlight: #0000000d;
  --border-light: #0000001a;
  --border-medium: #00000026;
  --border-heavy: #0003;
  --border-xheavy: #00000040;
  --border-sharp: #0000000d;
  --main-surface-primary: var(--white);
  --main-surface-primary-inverse: var(--gray-800);
  --main-surface-secondary: var(--gray-50);
  --main-surface-secondary-selected: #0000001a;
  --main-surface-tertiary: var(--gray-100);
  --sidebar-surface-primary: var(--gray-50);
  --sidebar-surface-secondary: var(--gray-100);
  --sidebar-surface-tertiary: var(--gray-200);
  --sidebar-title-primary: #28282880;
  --sidebar-surface: #fcfcfc;
  --sidebar-body-primary: #0d0d0d;
  --sidebar-icon: #7d7d7d;
  --surface-hover: #00000012;
  --link: #2964aa;
  --link-hover: #749ac8;
  --scrollbar-color: #0000001a;
  --scrollbar-color-hover: #0003;
  --header-height: calc(13 * var(--spacing));
  --sidebar-width: 260px;
  --composer-bar-height: 52px;
  --composer-width: 768px;
  --shadow-soft: 0 1px 2px rgba(0, 0, 0, 0.06);
}

body.dark {
  color-scheme: dark;
  --main-surface-background: #212121e6;
  --message-surface: #323232d9;
  --composer-blue-bg: #2a4a6d;
  --composer-blue-hover: #1a416a;
  --composer-blue-hover-tint: #0084ff24;
  --composer-surface-primary: #303030;
  --dot-color: var(--white);
  --text-primary: var(--gray-100);
  --text-primary-inverse: var(--gray-950);
  --text-secondary: #ffffffb3;
  --text-tertiary: #ffffff94;
  --text-quaternary: #ffffff69;
  --text-placeholder: #fffc;
  --border-xlight: #ffffff0d;
  --border-light: #ffffff1a;
  --border-medium: #ffffff26;
  --border-heavy: #fff3;
  --border-xheavy: #ffffff40;
  --border-sharp: #ffffff0d;
  --main-surface-primary: var(--gray-800);
  --main-surface-primary-inverse: var(--white);
  --main-surface-secondary: var(--gray-750);
  --main-surface-secondary-selected: #ffffff26;
  --main-surface-tertiary: var(--gray-700);
  --sidebar-surface-primary: var(--gray-900);
  --sidebar-surface-secondary: var(--gray-800);
  --sidebar-surface-tertiary: var(--gray-750);
  --sidebar-title-primary: #f0f0f080;
  --sidebar-surface: #2b2b2b;
  --sidebar-body-primary: #ededed;
  --sidebar-icon: #a4a4a4;
  --surface-hover: #ffffff26;
  --link: #7ab7ff;
  --link-hover: #5e83b3;
  --scrollbar-color: #ffffff1a;
  --scrollbar-color-hover: #fff3;
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  font-family: "OpenAI Sans", "Segoe UI", Helvetica, Arial, sans-serif;
  background: var(--main-surface-background);
  color: var(--text-primary);
  font-size: 14px;
  line-height: 1.5;
}

::-webkit-scrollbar {
  width: 10px;
}

::-webkit-scrollbar-thumb {
  background: var(--scrollbar-color);
  border-radius: 999px;
}

::-webkit-scrollbar-thumb:hover {
  background: var(--scrollbar-color-hover);
}

.app {
  display: grid;
  grid-template-columns: var(--sidebar-width) 1fr;
  min-height: 100vh;
}

.sidebar {
  background: var(--sidebar-surface);
  border-right: 1px solid var(--border-light);
  display: flex;
  flex-direction: column;
  gap: calc(var(--spacing) * 4);
  padding: calc(var(--spacing) * 3);
}

.sidebar-header {
  padding: 0 calc(var(--spacing) * 1);
}

.btn {
  border: 1px solid var(--border-light);
  border-radius: 10px;
  padding: 8px 12px;
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  font-family: inherit;
  color: var(--text-primary);
  background: var(--main-surface-secondary);
}

.btn:hover {
  background: var(--surface-hover);
}

.btn.primary {
  background: var(--gray-900);
  color: #fff;
  border-color: transparent;
}

.btn.primary:hover {
  background: var(--gray-800);
}

.btn.ghost {
  background: transparent;
  border-color: var(--border-light);
}

.btn.small {
  padding: 6px 10px;
  font-size: 12px;
}

.btn.full {
  width: 100%;
}

.btn.new-chat {
  width: 100%;
  display: flex;
  align-items: center;
  gap: 8px;
  background: var(--main-surface-primary);
  border: 1px solid var(--border-light);
}

.btn.new-chat .plus {
  font-size: 16px;
  line-height: 1;
}

.sidebar-section {
  display: flex;
  flex-direction: column;
  gap: calc(var(--spacing) * 2);
}

.section-title {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--sidebar-title-primary);
  padding: 0 calc(var(--spacing) * 1);
}

.sidebar-list {
  display: flex;
  flex-direction: column;
  gap: 2px;
}

.list-item {
  padding: 8px 10px;
  border-radius: 10px;
  cursor: pointer;
  display: flex;
  flex-direction: column;
  gap: 2px;
  color: var(--sidebar-body-primary);
}

.list-item:hover {
  background: var(--main-surface-secondary);
}

.list-item.active {
  background: var(--main-surface-tertiary);
  box-shadow: inset 0 0 0 1px var(--border-light);
}

.list-item .title {
  font-size: 13px;
}

.list-item .meta {
  font-size: 11px;
  color: var(--text-tertiary);
}

.pair-box {
  display: flex;
  gap: 8px;
}

.pair-box input {
  flex: 1;
  height: 34px;
  padding: 0 10px;
  border-radius: 10px;
  border: 1px solid var(--border-light);
  background: var(--main-surface-primary);
  color: var(--text-primary);
  text-transform: uppercase;
  letter-spacing: 0.1em;
  font-size: 12px;
}

.pair-hint {
  font-size: 11px;
  color: var(--text-tertiary);
  margin: 0;
}

.sidebar-footer {
  margin-top: auto;
  border-top: 1px solid var(--border-light);
  padding-top: calc(var(--spacing) * 3);
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.user-label {
  font-size: 12px;
  color: var(--text-secondary);
}

.chat {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
  background: var(--main-surface-primary);
}

.chat-header {
  height: var(--header-height);
  border-bottom: 1px solid var(--border-light);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  background: var(--main-surface-primary);
  position: sticky;
  top: 0;
  z-index: 5;
}

.model-pill {
  font-size: 13px;
  color: var(--text-secondary);
  border: 1px solid var(--border-light);
  background: var(--main-surface-secondary);
  padding: 6px 12px;
  border-radius: 999px;
}

.status {
  font-size: 11px;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  color: var(--text-tertiary);
}

.message-list {
  flex: 1;
  overflow-y: auto;
  padding: calc(var(--spacing) * 4) 0 calc(var(--spacing) * 18);
  scrollbar-gutter: stable;
}

.message-row {
  padding: calc(var(--spacing) * 5) 0;
}

.message-inner {
  max-width: var(--composer-width);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  gap: 12px;
  align-items: flex-start;
}

.message-row.user .message-inner {
  flex-direction: row-reverse;
}

.avatar {
  width: 28px;
  height: 28px;
  border-radius: 8px;
  display: grid;
  place-items: center;
  font-size: 11px;
  font-weight: 600;
  background: var(--gray-900);
  color: #fff;
  flex-shrink: 0;
}

.avatar.user {
  background: var(--composer-blue-bg);
  color: var(--text-primary);
  border: 1px solid var(--composer-blue-hover);
}

.message-content {
  line-height: 1.6;
  white-space: pre-wrap;
  font-size: 14.5px;
  background: var(--message-surface);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 10px 14px;
  box-shadow: var(--shadow-soft);
  max-width: 100%;
}

.message-row.user .message-content {
  background: var(--composer-blue-bg);
  border-color: var(--composer-blue-hover);
}

.message-row.streaming .message-content::after {
  content: "▍";
  margin-left: 4px;
  color: var(--dot-color);
  animation: blink 1s steps(1) infinite;
}

.system-card {
  background: var(--main-surface-secondary);
  border: 1px solid var(--border-light);
  border-radius: 12px;
  padding: 12px 14px;
  font-size: 13px;
  box-shadow: var(--shadow-soft);
}

.system-card strong {
  display: block;
  margin-bottom: 6px;
  font-size: 12px;
  color: var(--text-secondary);
}

.system-actions {
  margin-top: 10px;
  display: flex;
  gap: 8px;
}

.composer {
  position: sticky;
  bottom: 0;
  padding: 12px 20px 24px;
  background: linear-gradient(to bottom, rgba(255, 255, 255, 0), var(--main-surface-primary) 40%);
}

body.dark .composer {
  background: linear-gradient(to bottom, rgba(0, 0, 0, 0), var(--main-surface-primary) 40%);
}

.composer-inner {
  max-width: var(--composer-width);
  margin: 0 auto;
  display: flex;
  align-items: flex-end;
  gap: 8px;
  background: var(--composer-surface-primary);
  border: 1px solid var(--border-light);
  border-radius: 16px;
  padding: 10px 12px;
  box-shadow: var(--shadow-soft);
}

.composer textarea {
  flex: 1;
  background: transparent;
  border: none;
  outline: none;
  color: var(--text-primary);
  font-size: 15px;
  line-height: 1.5;
  resize: none;
  font-family: inherit;
}

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

.send-button {
  width: 32px;
  height: 32px;
  border-radius: 999px;
  border: none;
  background: var(--gray-900);
  color: #fff;
  display: grid;
  place-items: center;
  cursor: pointer;
}

.send-button:hover {
  background: var(--gray-800);
}

.send-button svg {
  width: 16px;
  height: 16px;
}

.composer-footer {
  max-width: var(--composer-width);
  margin: 8px auto 0;
  display: flex;
  justify-content: space-between;
  align-items: center;
  color: var(--text-tertiary);
  font-size: 12px;
}

.hint {
  color: var(--text-tertiary);
}

.login-screen {
  position: fixed;
  inset: 0;
  display: grid;
  place-items: center;
  background: var(--main-surface-primary);
  z-index: 10;
}

.login-screen.hidden {
  display: none;
}

.login-card {
  background: var(--main-surface-primary);
  border: 1px solid var(--border-light);
  border-radius: 16px;
  padding: 32px;
  width: 320px;
  text-align: center;
  display: flex;
  flex-direction: column;
  gap: 12px;
  box-shadow: var(--shadow-soft);
}

.login-mark {
  width: 48px;
  height: 48px;
  border-radius: 14px;
  margin: 0 auto;
  background: var(--gray-900);
  display: grid;
  place-items: center;
}

.login-dot {
  width: 10px;
  height: 10px;
  border-radius: 999px;
  background: #fff;
}

.login-card h1 {
  font-size: 18px;
  margin: 0;
}

.login-card .subtitle {
  color: var(--text-secondary);
  font-size: 13px;
  margin: 0 0 8px;
}

@keyframes blink {
  50% {
    opacity: 0;
  }
}

@media (max-width: 900px) {
  .app {
    grid-template-columns: 1fr;
  }
  .sidebar {
    display: none;
  }
  .chat-header {
    padding: 0 16px;
  }
  .message-inner {
    padding: 0 16px;
  }
  .composer {
    padding: 12px 16px 24px;
  }
}