/* ============================================================
   CSS Custom Properties
   ============================================================ */
:root {
  --color-bg:            #f9f7f4;
  --color-surface:       #ffffff;
  --color-border:        #e8e2d9;
  --color-accent:        #6b3f2a;   /* deep crimson */
  --color-accent-hover:  #7e4b32;
  --color-accent-light:  #f4ede8;
  --color-text:          #2d2418;
  --color-text-muted:    #8a7a6a;
  --color-error-bg:      #fff0ee;
  --color-error-border:  #f5c6c0;
  --color-error-text:    #8b2020;

  --font-serif:  Georgia, 'Times New Roman', serif;
  --font-sans:   'Segoe UI', system-ui, -apple-system, sans-serif;
  --font-mono:   'Fira Code', 'Courier New', monospace;

  --radius:      12px;
  --radius-sm:   6px;
  --max-width:   780px;
  --header-h:    56px;
  --footer-h:    auto;
  --shadow-sm:   0 1px 3px rgba(0,0,0,.07);
  --shadow-md:   0 4px 16px rgba(0,0,0,.10);

  --transition:  .22s ease;
}

/* ============================================================
   Reset & Base
   ============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

html, body {
  height: 100%;
  font-family: var(--font-sans);
  color: var(--color-text);
  background: var(--color-bg);
  -webkit-font-smoothing: antialiased;
}

body {
  display: flex;
  flex-direction: column;
  height: 100dvh;
  overflow: hidden;
}

/* ============================================================
   App Shell
   ============================================================ */
#app {
  display: flex;
  flex-direction: column;
  height: 100dvh;
  width: 100%;
}

/* ============================================================
   Header
   ============================================================ */
#app-header {
  flex-shrink: 0;
  height: var(--header-h);
  background: var(--color-surface);
  border-bottom: 1px solid var(--color-border);
  box-shadow: var(--shadow-sm);
  z-index: 10;
}

.header-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 16px;
  height: 100%;
}

.header-title {
  display: flex;
  align-items: center;
  gap: 8px;
}

.header-icon {
  font-size: 18px;
  color: var(--color-accent);
  line-height: 1;
}

.header-title h1 {
  font-family: var(--font-serif);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--color-accent);
  letter-spacing: .02em;
}

.header-subtitle {
  font-size: .75rem;
  color: var(--color-text-muted);
  border-left: 1px solid var(--color-border);
  padding-left: 8px;
  margin-left: 2px;
}

#settings-btn {
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: none;
  border-radius: 50%;
  background: transparent;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: background var(--transition), color var(--transition);
}
#settings-btn:hover {
  background: var(--color-accent-light);
  color: var(--color-accent);
}

/* ============================================================
   Chat Container
   ============================================================ */
#chat-container {
  flex: 1;
  overflow-y: auto;
  scroll-behavior: smooth;
  padding: 24px 16px 8px;
}

#messages {
  max-width: var(--max-width);
  margin: 0 auto;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

/* ============================================================
   Message Bubbles
   ============================================================ */
.message {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  animation: fadeSlideIn .18s ease;
}

@keyframes fadeSlideIn {
  from { opacity: 0; transform: translateY(6px); }
  to   { opacity: 1; transform: translateY(0); }
}

/* User — right aligned */
.message.user {
  flex-direction: row-reverse;
  margin-left: auto;
  max-width: 75%;
}

.message.user .bubble {
  background: var(--color-accent);
  color: #ffffff;
  border-radius: var(--radius) var(--radius) 4px var(--radius);
  font-size: .95rem;
  line-height: 1.55;
  white-space: pre-wrap;
  word-break: break-word;
}

/* Assistant — left aligned */
.message.assistant {
  margin-right: auto;
  max-width: 82%;
}

.message.assistant .bubble {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius) var(--radius) var(--radius) 4px;
  font-family: var(--font-serif);
  font-size: .97rem;
  line-height: 1.7;
  color: var(--color-text);
  box-shadow: var(--shadow-sm);
}

/* Shared bubble styles */
.bubble {
  padding: 12px 16px;
  word-wrap: break-word;
}

/* Markdown content inside assistant bubbles */
.message.assistant .bubble p { margin: 0 0 .75em; }
.message.assistant .bubble p:last-child { margin-bottom: 0; }
.message.assistant .bubble h1,
.message.assistant .bubble h2,
.message.assistant .bubble h3 {
  font-family: var(--font-serif);
  font-weight: 700;
  margin: .9em 0 .4em;
  color: var(--color-accent);
}
.message.assistant .bubble h1 { font-size: 1.15rem; }
.message.assistant .bubble h2 { font-size: 1.05rem; }
.message.assistant .bubble h3 { font-size: .97rem; }
.message.assistant .bubble strong { color: var(--color-accent); }
.message.assistant .bubble em { font-style: italic; }
.message.assistant .bubble ul,
.message.assistant .bubble ol { padding-left: 1.4em; margin: .5em 0; }
.message.assistant .bubble li { margin-bottom: .25em; }
.message.assistant .bubble blockquote {
  border-left: 3px solid var(--color-accent);
  margin: .6em 0;
  padding: .3em .8em;
  color: var(--color-text-muted);
  font-style: italic;
}
.message.assistant .bubble code {
  font-family: var(--font-mono);
  font-size: .88em;
  background: var(--color-accent-light);
  padding: .1em .35em;
  border-radius: var(--radius-sm);
}
.message.assistant .bubble pre {
  background: #f3ede8;
  border-radius: var(--radius-sm);
  padding: .8em 1em;
  overflow-x: auto;
  margin: .6em 0;
}
.message.assistant .bubble pre code {
  background: none;
  padding: 0;
  font-size: .87em;
}
.message.assistant .bubble a {
  color: var(--color-accent);
  text-decoration: underline;
}
.message.assistant .bubble hr {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: .8em 0;
}

/* Group spacing: less space between consecutive messages from same role */
.message + .message.user  { margin-top: 2px; }
.message + .message.assistant { margin-top: 2px; }
.message.user  + .message.assistant { margin-top: 12px; }
.message.assistant + .message.user  { margin-top: 12px; }

/* ============================================================
   Typing Indicator
   ============================================================ */
#typing-indicator {
  display: none;
  max-width: var(--max-width);
  margin: 8px auto 0;
}

#typing-indicator.visible {
  display: flex;
}

.typing-bubble {
  display: flex;
  align-items: center;
  gap: 5px;
  padding: 14px 18px;
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: var(--radius) var(--radius) var(--radius) 4px;
  box-shadow: var(--shadow-sm);
}

.dot {
  width: 7px;
  height: 7px;
  background: var(--color-text-muted);
  border-radius: 50%;
  animation: bounce 1.3s infinite ease-in-out;
}
.dot:nth-child(2) { animation-delay: .18s; }
.dot:nth-child(3) { animation-delay: .36s; }

@keyframes bounce {
  0%, 80%, 100% { transform: translateY(0);   opacity: .5; }
  40%           { transform: translateY(-6px); opacity: 1; }
}

/* ============================================================
   Error bubble
   ============================================================ */
.message.error .bubble {
  background: var(--color-error-bg);
  border: 1px solid var(--color-error-border);
  border-radius: var(--radius);
  color: var(--color-error-text);
  font-size: .9rem;
}

/* ============================================================
   Welcome message
   ============================================================ */
.welcome {
  text-align: center;
  padding: 40px 20px 24px;
  color: var(--color-text-muted);
  max-width: var(--max-width);
  margin: 0 auto;
}
.welcome-icon {
  font-size: 2.4rem;
  color: var(--color-accent);
  margin-bottom: 12px;
  display: block;
  opacity: .8;
}
.welcome h2 {
  font-family: var(--font-serif);
  font-size: 1.3rem;
  color: var(--color-text);
  margin-bottom: 8px;
}
.welcome p {
  font-size: .9rem;
  line-height: 1.6;
  max-width: 480px;
  margin: 0 auto;
}
.welcome .api-warning {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  margin-top: 16px;
  padding: 8px 14px;
  background: #fff8e1;
  border: 1px solid #f0d060;
  border-radius: var(--radius-sm);
  font-size: .82rem;
  color: #7a5c00;
}

/* ============================================================
   Input Area
   ============================================================ */
#input-area {
  flex-shrink: 0;
  background: var(--color-surface);
  border-top: 1px solid var(--color-border);
  padding: 12px 16px 10px;
}

.input-inner {
  display: flex;
  align-items: flex-end;
  gap: 8px;
  max-width: var(--max-width);
  margin: 0 auto;
  background: var(--color-surface);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius);
  padding: 8px 8px 8px 14px;
  transition: border-color var(--transition), box-shadow var(--transition);
}
.input-inner:focus-within {
  border-color: var(--color-accent);
  box-shadow: 0 0 0 3px rgba(107,63,42,.1);
}

#user-input {
  flex: 1;
  border: none;
  outline: none;
  background: transparent;
  font-family: var(--font-sans);
  font-size: .95rem;
  color: var(--color-text);
  resize: none;
  line-height: 1.5;
  max-height: 144px; /* ~6 lines */
  overflow-y: auto;
}
#user-input::placeholder { color: var(--color-text-muted); }
#user-input:disabled { opacity: .5; }

#send-btn {
  flex-shrink: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  border: none;
  border-radius: var(--radius-sm);
  background: var(--color-accent);
  color: #fff;
  cursor: pointer;
  transition: background var(--transition), opacity var(--transition);
}
#send-btn:hover  { background: var(--color-accent-hover); }
#send-btn:disabled { opacity: .45; cursor: not-allowed; }

#input-hint {
  text-align: center;
  font-size: .72rem;
  color: var(--color-text-muted);
  margin-top: 6px;
}
#input-hint kbd {
  font-family: var(--font-mono);
  font-size: .7rem;
  background: var(--color-bg);
  border: 1px solid var(--color-border);
  border-radius: 3px;
  padding: 1px 4px;
}

/* ============================================================
   Settings Panel
   ============================================================ */
#settings-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,.25);
  z-index: 99;
}
#settings-overlay.visible { display: block; }

#settings-panel {
  position: fixed;
  top: 0;
  right: 0;
  bottom: 0;
  width: 320px;
  background: var(--color-surface);
  border-left: 1px solid var(--color-border);
  box-shadow: var(--shadow-md);
  z-index: 100;
  padding: 24px 20px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 10px;
  transform: translateX(100%);
  transition: transform var(--transition);
}
#settings-panel.open { transform: translateX(0); }

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 8px;
}
.settings-header h2 {
  font-family: var(--font-serif);
  font-size: 1.05rem;
  color: var(--color-text);
}
#settings-close-btn {
  width: 30px;
  height: 30px;
  border: none;
  background: transparent;
  font-size: 1.3rem;
  color: var(--color-text-muted);
  cursor: pointer;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  line-height: 1;
  transition: background var(--transition);
}
#settings-close-btn:hover { background: var(--color-accent-light); color: var(--color-accent); }

#settings-panel label {
  display: block;
  font-size: .8rem;
  font-weight: 600;
  color: var(--color-text-muted);
  text-transform: uppercase;
  letter-spacing: .05em;
  margin-top: 4px;
}

#settings-panel input,
#settings-panel select {
  width: 100%;
  padding: 9px 12px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: var(--color-bg);
  font-family: var(--font-sans);
  font-size: .9rem;
  color: var(--color-text);
  outline: none;
  transition: border-color var(--transition);
}
#settings-panel input:focus,
#settings-panel select:focus {
  border-color: var(--color-accent);
}

.settings-hint {
  font-size: .78rem;
  color: var(--color-text-muted);
  line-height: 1.5;
}
.settings-hint code {
  font-family: var(--font-mono);
  font-size: .8em;
  background: var(--color-accent-light);
  padding: .1em .3em;
  border-radius: 3px;
}

.settings-divider {
  border: none;
  border-top: 1px solid var(--color-border);
  margin: 8px 0;
}

.btn-secondary {
  width: 100%;
  padding: 9px 16px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  background: transparent;
  font-family: var(--font-sans);
  font-size: .88rem;
  color: var(--color-text-muted);
  cursor: pointer;
  transition: border-color var(--transition), color var(--transition), background var(--transition);
  text-align: center;
}
.btn-secondary:hover {
  border-color: var(--color-accent);
  color: var(--color-accent);
  background: var(--color-accent-light);
}

.proxy-status {
  margin-top: 4px;
  font-size: .78rem;
  color: var(--color-text-muted);
  min-height: 20px;
}
.proxy-status.active  { color: #2e7d32; }
.proxy-status.direct  { color: var(--color-text-muted); }

/* ============================================================
   Scrollbar (webkit)
   ============================================================ */
#chat-container::-webkit-scrollbar { width: 6px; }
#chat-container::-webkit-scrollbar-track { background: transparent; }
#chat-container::-webkit-scrollbar-thumb { background: var(--color-border); border-radius: 3px; }

/* ============================================================
   Responsive — 600px breakpoint
   ============================================================ */
@media (max-width: 600px) {
  .header-subtitle { display: none; }

  .message.user      { max-width: 88%; }
  .message.assistant { max-width: 94%; }

  #settings-panel {
    width: 100%;
    top: auto;
    right: 0;
    left: 0;
    bottom: 0;
    height: 75dvh;
    border-left: none;
    border-top: 1px solid var(--color-border);
    border-radius: var(--radius) var(--radius) 0 0;
    transform: translateY(100%);
    transition: transform var(--transition);
  }
  #settings-panel.open { transform: translateY(0); }

  #input-hint { display: none; }
}