@import url("https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600&display=swap");

:root {
  /* Common variables */
  --font-family: "Inter", -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  
  /* Light Theme */
  --bg-primary: #ffffff;
  --bg-secondary: #f4f6f8;
  --bg-hover: #f0f2f5;
  
  --text-primary: #1a1c1e;
  --text-secondary: #64748b;
  --text-tertiary: #94a3b8;
  
  --border-color: #e2e8f0;
  --border-hover: #cbd5e1;
  
  --accent-color: #000000; /* Minimalist black for actions */
  --accent-text: #ffffff;
  
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -1px rgba(0, 0, 0, 0.06);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
  
  --sidebar-width: 280px;
}

[data-theme="dark"] {
  /* Dark Theme - Modern Soft Dark (inspired by Linear/Notion) */
  --bg-primary: #1a1a1a;
  --bg-secondary: #242424;
  --bg-hover: #2e2e2e;

  --text-primary: #ececec;
  --text-secondary: #a0a0a0;
  --text-tertiary: #6b6b6b;

  --border-color: #333333;
  --border-hover: #444444;

  --accent-color: #ffffff;
  --accent-text: #1a1a1a;

  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.3);
  --shadow-md: 0 4px 6px -1px rgba(0, 0, 0, 0.4), 0 2px 4px -1px rgba(0, 0, 0, 0.3);
  --shadow-xl: 0 20px 25px -5px rgba(0, 0, 0, 0.3), 0 10px 10px -5px rgba(0, 0, 0, 0.2);
}

* {
  box-sizing: border-box;
}

/* Global theme transition for smooth color changes */
*,
*::before,
*::after {
  transition: background-color 0.3s ease,
              border-color 0.3s ease,
              color 0.3s ease,
              box-shadow 0.3s ease;
}

/* Disable transition for specific elements that shouldn't animate */
input, textarea, button, .thinking-step {
  transition: background-color 0.2s ease,
              border-color 0.2s ease,
              color 0.2s ease,
              box-shadow 0.2s ease,
              transform 0.15s ease,
              opacity 0.15s ease;
}

body {
  margin: 0;
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  line-height: 1.5;
}

/* Layout */
.app {
  display: flex;
  min-height: 100vh;
}

.sidebar {
  width: var(--sidebar-width);
  height: 100vh;
  position: sticky;
  top: 0;
  background: var(--bg-secondary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  padding: 24px 20px;
  overflow-y: auto;
  flex-shrink: 0;
  z-index: 10;
}

.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  height: 100vh; /* Constrain height to viewport */
  position: relative;
  transition: background 0.3s ease;
}

/* Sidebar Components */
.sidebar-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 32px;
}

.sidebar-header-actions {
  display: flex;
  align-items: center;
  gap: 4px;
}

/* Close sidebar button - hidden on mobile */
.close-sidebar-btn {
  display: flex;
}

@media (max-width: 768px) {
  .close-sidebar-btn {
    display: none;
  }
}

/* Sidebar collapsed state for desktop */
.sidebar.collapsed {
  width: 0;
  padding: 0;
  overflow: hidden;
  border-right: none;
}

.sidebar.collapsed * {
  opacity: 0;
  visibility: hidden;
  transition: opacity 0.1s ease, visibility 0.1s ease;
}

/* Transition for smooth collapse/expand */
.sidebar {
  transition: width 0.3s ease, padding 0.3s ease;
}

.sidebar * {
  transition: opacity 0.2s ease 0.1s, visibility 0.2s ease 0.1s;
}

.brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  font-size: 18px;
  white-space: nowrap;
}

.brand-logo {
  background: var(--accent-color);
  color: var(--accent-text);
  padding: 4px 8px;
  border-radius: 6px;
  font-weight: 700;
  font-size: 14px;
}

.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s;
}

.icon-btn:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-links {
  margin-bottom: 24px;
}

.nav-item {
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.2s;
}

.nav-item.active {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.nav-item:hover {
  color: var(--text-primary);
}

.side-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 24px;
}

.btn-primary {
  background: var(--accent-color);
  color: var(--accent-text);
  border: none;
  padding: 12px;
  border-radius: 8px;
  font-family: inherit;
  font-weight: 500; /* Regular weight look */
  font-size: 14px;
  cursor: pointer;
  transition: opacity 0.2s;
  width: 100%;
}

.btn-primary:hover {
  opacity: 0.9;
}

.suggestions {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.suggestion-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  margin-bottom: 4px;
  letter-spacing: 0.5px;
}

.chip {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 13px;
  text-align: left;
  cursor: pointer;
  transition: all 0.2s;
  font-family: inherit;
}

.chip:hover {
  background: var(--bg-hover);
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.sidebar-footer {
  margin-top: auto;
  padding-top: 12px;
  border-top: 1px solid var(--border-color);
}

.friend-links {
  margin-bottom: 12px;
  padding-bottom: 12px;
  border-bottom: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 6px;
}

.friend-links-title {
  font-size: 11px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.friend-link {
  font-size: 12px;
  color: var(--text-secondary);
  text-decoration: none;
  transition: color 0.2s;
}

.friend-link:hover {
  color: var(--accent-color);
}

.footer-text {
  font-size: 12px;
  color: var(--text-tertiary);
  display: block;
  text-align: center;
}

.footer-icp {
  font-size: 11px;
  color: var(--text-tertiary);
  text-decoration: none;
  display: block;
  text-align: center;
  margin-top: 6px;
}

.footer-icp:hover {
  color: var(--accent-color);
}

/* =============================================================================
   History Section
   ============================================================================= */
.history-section {
  display: flex;
  flex-direction: column;
  gap: 8px;
  flex: 1;
  min-height: 0;
}

.history-title {
  font-size: 12px;
  font-weight: 600;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 4px;
  overflow-y: auto;
  flex: 1;
}

.history-item {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 10px 12px;
  border-radius: 8px;
  font-size: 13px;
  color: var(--text-secondary);
  cursor: pointer;
  transition: all 0.15s;
  background: transparent;
  border: none;
  text-align: left;
  width: 100%;
}

.history-item:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.history-item.active {
  background: var(--bg-hover);
  color: var(--text-primary);
}

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

.history-item-time {
  font-size: 11px;
  color: var(--text-tertiary);
  flex-shrink: 0;
}

.history-item-delete {
  opacity: 0;
  background: transparent;
  border: none;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: 2px;
  border-radius: 4px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s;
}

.history-item:hover .history-item-delete {
  opacity: 1;
}

.history-item-delete:hover {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

.history-empty {
  font-size: 13px;
  color: var(--text-tertiary);
  text-align: center;
  padding: 20px 0;
}

/* Main Content Components */
.top-bar {
  flex-shrink: 0;
  padding: 16px 32px;
  border-bottom: 1px solid var(--border-color);
  background: rgba(255, 255, 255, 0.8);
  backdrop-filter: blur(12px);
  position: sticky;
  top: 0;
  z-index: 5;
}

[data-theme="dark"] .top-bar {
  background: rgba(26, 26, 26, 0.9);
}

.page-title {
  font-size: 16px;
  font-weight: 600;
  margin: 0;
}

.chat-area {
  flex: 1;
  overflow-y: auto;
  padding: 32px;
  display: flex;
  flex-direction: column;
  gap: 24px;
  scroll-behavior: smooth;
}

.input-area {
  flex-shrink: 0;
  padding: 24px 32px 32px;
  background: var(--bg-primary);
  border-top: 1px solid var(--border-color);
  transition: background 0.3s ease;
}

.composer-wrapper {
  position: relative;
  max-width: 800px;
  margin: 0 auto;
}

.input-field {
  width: 100%;
  background: var(--bg-secondary);
  border: 1px solid transparent;
  border-radius: 12px;
  padding: 16px 48px 16px 16px; 
  color: var(--text-primary);
  font-family: inherit;
  font-size: 15px;
  line-height: 1.5;
  resize: none;
  box-shadow: none;
  transition: all 0.2s;
  outline: none;
}

.input-field:focus {
  background: var(--bg-primary);
  border-color: var(--border-hover);
  box-shadow: 0 0 0 2px var(--bg-hover);
}

.send-btn {
  position: absolute;
  right: 8px;
  top: 50%;
  transform: translateY(-50%);
  background: transparent;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, color 0.2s;
}

.send-btn svg {
  display: block;
}

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

.input-hint {
  text-align: center;
  font-size: 12px;
  color: var(--text-tertiary);
  margin-top: 12px;
}

.input-hint a {
  color: var(--text-tertiary);
  text-decoration: none;
}

.input-hint a:hover {
  color: var(--accent-color);
}

/* Messages */
.msg-row {
  max-width: 800px;
  margin: 0 auto;
  width: 100%;
  display: flex;
  gap: 16px;
}

.msg-row.user {
  flex-direction: row-reverse;
}

.avatar {
  flex-shrink: 0;
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 12px;
  font-weight: 500;
}

.msg-row.user .avatar {
  background: var(--text-primary);
  color: var(--bg-primary);
}

.msg-row.assistant .avatar {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.content {
  flex: 1;
  font-size: 15px;
  line-height: 1.6;
  max-width: 80%;
}

.msg-row.user .content {
  background: var(--bg-secondary);
  padding: 12px 16px;
  border-radius: 16px;
  border-top-right-radius: 4px;
}

.msg-row.assistant .content {
  padding-top: 4px; /* Align with avatar */
}

/* Markdown Styles */
.content h1, .content h2, .content h3 {
  margin-top: 1.5em;
  margin-bottom: 0.5em;
  font-weight: 600;
  line-height: 1.3;
}
.content h1 { font-size: 1.4em; }
.content h2 { font-size: 1.25em; }
.content p { margin-bottom: 1em; }
.content pre {
  background: var(--bg-secondary);
  padding: 16px;
  border-radius: 8px;
  overflow-x: auto;
  border: 1px solid var(--border-color);
}
.content code {
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, Courier, monospace;
  font-size: 0.9em;
}
.content ul, .content ol {
  padding-left: 20px;
  margin-bottom: 1em;
}
.content li {
  margin-bottom: 0.4em;
}
.content a {
  color: var(--text-primary);
  text-decoration: underline;
  text-decoration-thickness: 1px;
  text-underline-offset: 2px;
}

/* Thinking Process */
.thinking-process {
  margin-bottom: 16px;
  font-size: 13px;
}

.thinking-process details > summary {
  cursor: pointer;
  color: var(--text-tertiary);
  list-style: none;
  user-select: none;
}
.thinking-process details > summary:hover {
  color: var(--text-secondary);
}
.thinking-process pre {
  margin-top: 8px;
  color: var(--text-secondary);
  background: var(--bg-secondary);
  border: none;
  font-size: 12px;
  white-space: pre-wrap;
}

/* =============================================================================
   Streaming Thinking Process (Real-time)
   ============================================================================= */
.thinking-process.streaming {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  padding: 12px 14px;
}

.thinking-process.finished {
  border-color: var(--border-color);
}

.thinking-header {
  display: flex;
  align-items: center;
  gap: 10px;
  margin-bottom: 10px;
  padding-bottom: 8px;
  border-bottom: 1px solid var(--border-color);
}

.thinking-title {
  font-weight: 500;
  color: var(--text-secondary);
  font-size: 13px;
}

.thinking-timer {
  margin-left: auto;
  font-family: "SFMono-Regular", Consolas, "Liberation Mono", Menlo, monospace;
  font-size: 12px;
  color: var(--text-tertiary);
}

.thinking-status {
  font-size: 12px;
  color: var(--text-tertiary);
  max-width: 180px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.thinking-content {
  max-height: 180px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.thinking-step {
  display: flex;
  align-items: flex-start;
  gap: 8px;
  padding: 5px 8px;
  background: var(--bg-primary);
  border-radius: 4px;
  font-size: 12px;
  line-height: 1.5;
  color: var(--text-secondary);
}

.thinking-step .step-label {
  flex-shrink: 0;
  font-size: 11px;
  font-weight: 500;
  color: var(--text-tertiary);
  text-transform: uppercase;
  letter-spacing: 0.3px;
  min-width: 32px;
}

.thinking-step.thinking {
  color: var(--text-secondary);
}

.thinking-step.tool_start {
  border-left: 2px solid var(--text-tertiary);
}

.thinking-step.tool_start .tool-name {
  font-weight: 500;
  color: var(--text-primary);
  margin-right: 6px;
}

.thinking-step.tool_start .tool-input {
  color: var(--text-tertiary);
  word-break: break-word;
}

.thinking-step.tool_end {
  border-left: 2px solid var(--text-tertiary);
}

.thinking-step.tool_end .tool-output {
  color: var(--text-secondary);
  word-break: break-word;
}

.thinking-step.error {
  border-left: 2px solid #dc2626;
  color: #dc2626;
}

[data-theme="dark"] .thinking-step.error {
  color: #f87171;
}

/* Collapsed thinking (after completion) */
.thinking-process .thinking-elapsed {
  font-family: "SFMono-Regular", Consolas, monospace;
  font-size: 12px;
  color: var(--text-tertiary);
}

.thinking-process .thinking-steps {
  margin-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 6px;
  max-height: 300px;
  overflow-y: auto;
}

::-webkit-scrollbar {
  width: 8px;
  height: 8px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--border-hover);
}

/* =============================================================================
   Login Confirmation Card
   ============================================================================= */
.login-card {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 12px;
  padding: 20px;
  margin: 8px 0;
  max-width: 400px;
}

.login-card-title {
  display: flex;
  align-items: center;
  gap: 10px;
  font-weight: 600;
  font-size: 16px;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.login-card-title svg {
  color: var(--accent-color);
}

.login-card-message {
  font-size: 14px;
  color: var(--text-secondary);
  margin-bottom: 16px;
  line-height: 1.5;
}

.login-card-buttons {
  display: flex;
  gap: 12px;
}

.login-card-buttons .btn-primary,
.login-card-buttons .btn-secondary {
  flex: 1;
  padding: 10px 16px;
  border-radius: 8px;
  font-size: 14px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.login-card-buttons .btn-secondary {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.login-card-buttons .btn-secondary:hover {
  background: var(--bg-hover);
  border-color: var(--border-hover);
  color: var(--text-primary);
}

/* =============================================================================
   Login Modal
   ============================================================================= */
.login-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  backdrop-filter: blur(4px);
}

.login-modal-content {
  background: var(--bg-primary);
  border: 1px solid var(--border-color);
  border-radius: 16px;
  width: 100%;
  max-width: 400px;
  margin: 16px;
  box-shadow: var(--shadow-md);
  animation: modalSlideIn 0.2s ease-out;
}

@keyframes modalSlideIn {
  from {
    opacity: 0;
    transform: translateY(-20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

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

.login-modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
}

.login-modal-header h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
}

.login-modal-close {
  background: transparent;
  border: none;
  font-size: 24px;
  color: var(--text-tertiary);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 6px;
  line-height: 1;
  transition: all 0.2s;
}

.login-modal-close:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.login-form {
  padding: 24px;
}

.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 14px;
  font-weight: 500;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.form-group input {
  width: 100%;
  padding: 12px 14px;
  font-size: 15px;
  font-family: inherit;
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: 8px;
  color: var(--text-primary);
  transition: all 0.2s;
  outline: none;
}

.form-group input:focus {
  border-color: var(--accent-color);
  box-shadow: 0 0 0 3px rgba(0, 0, 0, 0.1);
}

[data-theme="dark"] .form-group input:focus {
  box-shadow: 0 0 0 3px rgba(255, 255, 255, 0.1);
}

.form-group input::placeholder {
  color: var(--text-tertiary);
}

.login-form-hint {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 13px;
  color: var(--text-tertiary);
  margin-bottom: 24px;
}

.login-form-hint svg {
  flex-shrink: 0;
}

.login-form-buttons {
  display: flex;
  gap: 12px;
}

.login-form-buttons .btn-primary,
.login-form-buttons .btn-secondary {
  flex: 1;
  padding: 12px 16px;
  border-radius: 8px;
  font-size: 15px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.login-form-buttons .btn-secondary {
  background: transparent;
  border: 1px solid var(--border-color);
  color: var(--text-secondary);
}

.login-form-buttons .btn-secondary:hover {
  background: var(--bg-hover);
  border-color: var(--border-hover);
  color: var(--text-primary);
}

.login-form-buttons .btn-primary:disabled {
  opacity: 0.6;
  cursor: not-allowed;
}

.login-error {
  margin-top: 16px;
  padding: 12px;
  background: #fee2e2;
  border: 1px solid #fecaca;
  border-radius: 8px;
  color: #dc2626;
  font-size: 14px;
}

[data-theme="dark"] .login-error {
  background: rgba(220, 38, 38, 0.15);
  border-color: rgba(220, 38, 38, 0.3);
  color: #fca5a5;
}

/* =============================================================================
   Login Status in Sidebar
   ============================================================================= */
.login-status {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--text-secondary);
  margin-bottom: 12px;
  padding: 8px 0;
}

.login-status-dot {
  width: 8px;
  height: 8px;
  background: #22c55e;
  border-radius: 50%;
  animation: pulse 2s infinite;
}

@keyframes pulse {
  0%, 100% {
    opacity: 1;
  }
  50% {
    opacity: 0.5;
  }
}

/* =============================================================================
   Announcement Modal (reuses login modal styling)
   ============================================================================= */
.announcement-modal {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1001;
  backdrop-filter: blur(4px);
  animation: fadeIn 0.2s ease-out;
}

.announcement-modal-content {
  background: var(--bg-primary);
  border-radius: 16px;
  width: 90%;
  max-width: 500px;
  max-height: 80vh;
  box-shadow: var(--shadow-xl);
  animation: modalSlideIn 0.2s ease-out;
  display: flex;
  flex-direction: column;
}

.announcement-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 24px;
  border-bottom: 1px solid var(--border-color);
}

.announcement-header h3 {
  margin: 0;
  font-size: 18px;
  font-weight: 600;
  color: var(--text-primary);
  display: flex;
  align-items: center;
  gap: 8px;
}

.announcement-close {
  background: transparent;
  border: none;
  font-size: 24px;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px 8px;
  border-radius: 4px;
}

.announcement-close:hover {
  background: var(--bg-hover);
  color: var(--text-primary);
}

.announcement-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1;
  line-height: 1.6;
  color: var(--text-primary);
}

.announcement-body p {
  margin: 0 0 12px;
}

.announcement-body p:last-child {
  margin-bottom: 0;
}

.announcement-footer {
  padding: 16px 24px;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: flex-end;
}

.announcement-footer .btn-primary {
  padding: 10px 24px;
}

/* =============================================================================
   Mobile Responsive Styles
   ============================================================================= */

/* Mobile menu button (hidden by default, shown on mobile or when sidebar collapsed) */
.mobile-menu-btn {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-primary);
  cursor: pointer;
  padding: 8px;
  border-radius: 8px;
}

.mobile-menu-btn:hover {
  background: var(--bg-hover);
}

/* Show menu button when sidebar is collapsed on desktop */
.sidebar.collapsed ~ .main-content .mobile-menu-btn {
  display: flex;
  align-items: center;
  justify-content: center;
}

/* Hide page title when sidebar is collapsed */
.sidebar.collapsed ~ .main-content .page-title {
  display: none;
}

/* Sidebar overlay for mobile */
.sidebar-overlay {
  display: none;
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.5);
  z-index: 99;
}

.sidebar-overlay.active {
  display: block;
}

/* Tablet styles (768px - 1024px) */
@media (max-width: 1024px) {
  :root {
    --sidebar-width: 260px;
  }

  .chat-area {
    padding: 24px;
  }

  .input-area {
    padding: 16px 24px 24px;
  }

  .top-bar {
    padding: 12px 24px;
  }
}

/* Mobile styles (< 768px) */
@media (max-width: 768px) {
  .app {
    flex-direction: column;
  }

  /* Show mobile menu button */
  .mobile-menu-btn {
    display: flex;
    align-items: center;
    justify-content: center;
  }

  /* Sidebar transforms to slide-out drawer on mobile */
  .sidebar {
    position: fixed;
    left: -100%;
    top: 0;
    width: 85%;
    max-width: 320px;
    height: 100vh;
    z-index: 100;
    transition: left 0.3s ease;
    padding: 20px 16px;
  }

  .sidebar.open {
    left: 0;
  }

  /* Override collapsed state on mobile - use open/close instead */
  .sidebar.collapsed {
    width: 85%;
    max-width: 320px;
    padding: 20px 16px;
    overflow: visible;
    left: -100%;
  }

  .sidebar.collapsed * {
    opacity: 1;
    visibility: visible;
  }

  .sidebar.collapsed.open {
    left: 0;
  }

  /* Main content takes full width */
  .main-content {
    width: 100%;
    height: 100vh;
  }

  /* Top bar adjustments */
  .top-bar {
    padding: 12px 16px;
    display: flex;
    align-items: center;
    gap: 12px;
  }

  .page-title {
    font-size: 15px;
  }

  /* Chat area adjustments */
  .chat-area {
    padding: 16px;
    gap: 16px;
  }

  .msg-row {
    gap: 12px;
  }

  .avatar {
    width: 28px;
    height: 28px;
    font-size: 10px;
  }

  .content {
    max-width: 85%;
    font-size: 14px;
  }

  .msg-row.user .content {
    padding: 10px 14px;
    border-radius: 14px;
    border-top-right-radius: 4px;
  }

  /* Input area adjustments */
  .input-area {
    padding: 12px 16px 16px;
  }

  .input-field {
    padding: 12px 44px 12px 14px;
    font-size: 16px; /* Prevent zoom on iOS */
    border-radius: 10px;
  }

  .send-btn {
    right: 6px;
    bottom: 6px;
  }

  .input-hint {
    font-size: 11px;
    margin-top: 8px;
  }

  /* Thinking process adjustments */
  .thinking-process.streaming {
    padding: 10px 12px;
  }

  .thinking-header {
    flex-wrap: wrap;
    gap: 6px;
  }

  .thinking-status {
    max-width: 120px;
  }

  .thinking-content {
    max-height: 150px;
  }

  .thinking-step {
    padding: 4px 6px;
    font-size: 11px;
  }

  /* Login card adjustments */
  .login-card {
    padding: 16px;
    max-width: 100%;
  }

  .login-card-title {
    font-size: 15px;
  }

  .login-card-message {
    font-size: 13px;
  }

  .login-card-buttons {
    flex-direction: column;
    gap: 8px;
  }

  /* Login modal adjustments */
  .login-modal-content {
    max-width: calc(100% - 32px);
    margin: 16px;
    border-radius: 12px;
  }

  .login-modal-header {
    padding: 16px 20px;
  }

  .login-modal-header h3 {
    font-size: 16px;
  }

  .login-form {
    padding: 20px;
  }

  .form-group input {
    padding: 10px 12px;
    font-size: 16px; /* Prevent zoom on iOS */
  }

  .login-form-buttons {
    flex-direction: column;
    gap: 8px;
  }

  /* Markdown content adjustments */
  .content pre {
    padding: 12px;
    font-size: 12px;
  }

  .content h1 { font-size: 1.25em; }
  .content h2 { font-size: 1.15em; }
}

/* Small mobile styles (< 480px) */
@media (max-width: 480px) {
  .sidebar {
    width: 90%;
  }

  .chat-area {
    padding: 12px;
    gap: 12px;
  }

  .content {
    max-width: 90%;
    font-size: 13px;
  }

  .avatar {
    width: 24px;
    height: 24px;
    font-size: 9px;
  }

  .msg-row {
    gap: 8px;
  }

  .input-field {
    padding: 10px 40px 10px 12px;
  }

  .thinking-content {
    max-height: 120px;
  }
}

/* Safe area insets for notched phones */
@supports (padding: env(safe-area-inset-bottom)) {
  .input-area {
    padding-bottom: calc(16px + env(safe-area-inset-bottom));
  }

  @media (max-width: 768px) {
    .input-area {
      padding-bottom: calc(12px + env(safe-area-inset-bottom));
    }
  }
}