:root {
  /* Redefine theme variables to match main.css */
  --bg-app: #121212;
  --bg-panel: #1E1E1E;
  --bg-panel-header: #252526;
  --bg-hover: #2C2C2C;
  --bg-input: #111111;
  --border-color: #333333;
  --text-primary: #E0E0E0;
  --text-secondary: #A0A0A0;
  --text-disabled: #505050;
  --focus-color: #409EFF;
  --color-up: #EB4D3D;
  --color-down: #009944;
  --bg-active: rgba(64, 158, 255, 0.12);
  --border-radius-base: 4px;
  
  --font-size-xs: 11px;
  --font-size-sm: 12px;
  --font-size-base: 13px;
  --fw-medium: 500;

  /* Sidebar */
  --sidebar-width: 140px;
  --sidebar-bg: var(--bg-panel);
  --sidebar-list-bg: var(--bg-app);
  --sidebar-item-border: var(--border-color);
  --sidebar-item-hover: var(--bg-hover);
  --sidebar-item-active: var(--bg-active);
  
  /* Message */
  --msg-self-bg: rgba(64, 158, 255, 0.15);
  --msg-self-text: var(--text-primary);
  --msg-other-bg: var(--bg-hover);
  --msg-other-border: var(--border-color);
  
  /* Input */
  --input-bg: var(--bg-input);
  --input-border: var(--border-color);
  --input-focus-border: var(--focus-color);
  
  /* Button */
  --btn-bg: var(--bg-hover);
  --btn-text: var(--text-primary);
  --btn-hover-bg: var(--bg-active);
  
  --scrollbar-track: transparent;
  --scrollbar-thumb: #4b4b4b;
}

body.theme-white {
  --bg-app: #F0F2F5;
  --bg-panel: #FFFFFF;
  --bg-panel-header: #FAFAFA;
  --bg-hover: #F5F7FA;
  --bg-input: #FFFFFF;
  --border-color: #DCDFE6;
  --text-primary: #303133;
  --text-secondary: #606266;
  --text-disabled: #C0C4CC;
  --focus-color: #409EFF;
  --color-up: #D9001B;
  --color-down: #009944;
  --bg-active: rgba(64, 158, 255, 0.1);
  
  --sidebar-bg: var(--bg-panel);
  --sidebar-list-bg: var(--bg-app);
  --sidebar-item-border: var(--border-color);
  --sidebar-item-hover: var(--bg-hover);
  --sidebar-item-active: var(--bg-active);
  
  --msg-self-bg: rgba(64, 158, 255, 0.1);
  --msg-self-text: var(--text-primary);
  --msg-other-bg: #FFFFFF;
  --msg-other-border: var(--border-color);
  
  --input-bg: #FFFFFF;
  --input-border: var(--border-color);
  --input-focus-border: var(--focus-color);
  
  --btn-bg: #F0F2F5;
  --btn-text: var(--text-primary);
  --btn-hover-bg: #E6E8EB;
  
  --scrollbar-thumb: #C0C4CC;

  background: var(--bg-app);
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html,
body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  background-color: var(--bg-app);
  background: var(--bg-app); /* Remove gradient */
  color: var(--text-primary);
  height: 100%;
  height: 100dvh; /* Mobile viewport fix */
  overflow: hidden; /* Prevent body scroll */
}

.chat-shell {
  height: 100%;
  width: 100%;
  display: flex;
  background: transparent;
  position: relative;
  overflow: hidden;
}

.chat-sidebar {
  width: var(--sidebar-width);
  border-right: 1px solid var(--border-color);
  padding: 0; /* padding moved to content/footer */
  font-size: 12px;
  color: var(--text-primary);
  flex-shrink: 0;
  background: var(--sidebar-bg);
  transition: transform 0.3s ease, width 0.3s ease;
  z-index: 20;
  display: flex;
  flex-direction: column;
}

.chat-sidebar-content {
  flex: 1;
  overflow-y: auto;
  padding: 8px 6px;
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) transparent;
}

.chat-sidebar-content::-webkit-scrollbar {
  width: 4px;
}
.chat-sidebar-content::-webkit-scrollbar-thumb {
  background-color: var(--scrollbar-thumb);
  border-radius: 4px;
}

.chat-sidebar-footer {
  padding: 8px 6px;
  border-top: 1px solid var(--border-color);
  background: rgba(0, 0, 0, 0.1);
}

.chat-logout-btn {
  width: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 8px;
  background: transparent;
  border: 1px solid var(--border-color);
  border-radius: 6px;
  color: var(--text-secondary);
  font-size: 12px;
  cursor: pointer;
  transition: all 0.2s;
}

.chat-logout-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  border-color: rgba(255, 255, 255, 0.2);
}

.chat-sidebar-section + .chat-sidebar-section {
  margin-top: 8px;
}

.chat-sidebar-title {
  font-size: var(--font-size-xs);
  color: var(--text-secondary);
  margin-bottom: 4px;
  font-weight: var(--fw-medium);
}

.chat-sidebar-list {
  border-radius: 8px;
  background: var(--sidebar-list-bg);
  border: 1px solid var(--border-color);
  overflow: hidden;
}

.chat-sidebar-item {
  padding: 6px 8px;
  cursor: pointer;
  border-bottom: 1px solid var(--sidebar-item-border);
  transition: all 0.2s;
  position: relative;
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: var(--font-size-sm);
  color: var(--text-primary);
}

.chat-sidebar-item:last-child {
  border-bottom: none;
}

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

.chat-sidebar-item-active {
  background: var(--bg-active);
  box-shadow: inset 2px 0 0 var(--focus-color);
}

.chat-sidebar-item-active .chat-sidebar-item-name {
  color: var(--focus-color);
  font-weight: var(--fw-medium);
}

.chat-sidebar-item-name {
  flex: 1;
  min-width: 0;
  font-size: var(--font-size-sm);
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  padding: 0 4px;
}

.chat-sidebar-item-close {
  margin-left: 6px;
  flex-shrink: 0;
  border: none;
  background: transparent;
  color: #9ca3af;
  cursor: pointer;
  padding: 2px;
  border-radius: 4px;
  transition: all 0.2s;
  display: flex;
  align-items: center;
  justify-content: center;
}

.chat-sidebar-item-close:hover {
  background: rgba(255, 255, 255, 0.1);
  color: #ef4444;
}

.chat-unread-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 8px;
  height: 8px;
  padding: 0 4px;
  border-radius: 999px;
  background-color: #10b981;
  color: #fff;
  font-size: 10px;
  line-height: 1;
  margin-left: 6px;
  box-shadow: 0 0 4px rgba(16, 185, 129, 0.4);
}

.chat-toggle-btn {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px;
  margin-right: 8px;
  border-radius: 4px;
  position: relative;
}

.chat-toggle-btn.has-unread::after {
  content: '';
  position: absolute;
  top: 2px;
  right: 2px;
  width: 8px;
  height: 8px;
  background-color: #ef4444; /* Red for attention when hidden */
  border-radius: 50%;
  border: 1px solid var(--sidebar-bg);
}

.chat-main {
  flex: 1;
  display: flex;
  flex-direction: column;
  padding: 8px;
  min-width: 0;
  position: relative;
}

.chat-header {
  padding: 0 4px 4px;
  display: flex;
  align-items: center;
  min-height: 24px;
}

/* Sidebar Toggle Button - Original location commented out as we moved styles up */
/* .chat-toggle-btn {
  display: none;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  cursor: pointer;
  padding: 4px;
  margin-right: 8px;
  border-radius: 4px;
}
.chat-toggle-btn:hover {
  background: var(--sidebar-item-hover);
  color: var(--text-primary);
} */

.chat-header-title {
  font-size: var(--font-size-sm);
  color: var(--text-secondary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.chat-messages {
  flex: 1;
  padding: 12px 12px 0;
  overflow-y: auto;
  min-height: 0;
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

.chat-messages::-webkit-scrollbar {
  width: 6px;
}

.chat-messages::-webkit-scrollbar-track {
  background: var(--scrollbar-track);
}

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

.chat-message {
  margin-bottom: 8px;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
}

.chat-message-meta {
  font-size: 11px;
  color: var(--text-secondary);
  margin-bottom: 2px;
}

.chat-message-content {
  display: inline-block;
  width: auto;
  max-width: 85%;
  padding: 6px 10px;
  border-radius: 10px;
  font-size: 13px;
  line-height: 1.4;
  word-break: break-word;
}

.chat-message-self .chat-message-content {
  margin-left: auto;
  background: var(--msg-self-bg);
  color: var(--msg-self-text);
}

.chat-message-other .chat-message-content {
  background: var(--msg-other-bg);
  border: 1px solid var(--msg-other-border);
  color: var(--text-primary);
}

.chat-message-content img {
  max-width: 100%;
  height: auto;
  border-radius: 8px;
  display: block;
}

.chat-input-section {
  padding: 8px 0 4px;
}

.chat-form {
  display: flex;
  gap: 6px;
  align-items: center;
}

.chat-input {
  flex: 1;
  min-width: 0; /* Important for flex items to shrink */
  padding: 8px 12px;
  border-radius: 999px;
  border: 1px solid var(--input-border);
  background: var(--input-bg);
  color: var(--text-primary);
  font-size: 13px;
  transition: border-color 0.2s;
}

.chat-input:focus {
  outline: none;
  border-color: var(--input-focus-border);
}

.chat-send,
.chat-upload {
  padding: 8px 14px;
  border-radius: 999px;
  border: none;
  cursor: pointer;
  font-size: 13px;
  font-weight: 500;
  white-space: nowrap;
  transition: background 0.2s;
}

.chat-send {
  color: var(--btn-text);
  background: var(--btn-bg);
}

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

.chat-upload {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 8px 12px;
  color: var(--text-primary);
  background: var(--sidebar-item-hover); /* Reusing hover color for secondary btn */
}

.chat-upload:hover {
  background: var(--sidebar-item-active);
}

.chat-image-modal {
  position: fixed;
  inset: 0;
  display: flex;
  align-items: center;
  justify-content: center;
  background: rgba(0, 0, 0, 0.7);
  z-index: 9999;
}

.chat-image-modal-content img {
  max-width: 90vw;
  max-height: 90vh;
  border-radius: 10px;
  box-shadow: 0 10px 40px rgba(0, 0, 0, 0.7);
}

.chat-send:disabled {
  opacity: 0.6;
  cursor: default;
}

/* Responsive & Collapsed State */

/* Mobile / Narrow Mode */
@media (max-width: 480px) {
  .chat-toggle-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
  }
  
  .chat-sidebar {
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 180px;
    transform: translateX(-100%);
    background: var(--sidebar-list-bg);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    box-shadow: 2px 0 10px rgba(0,0,0,0.2);
  }
  
  .chat-sidebar.active {
    transform: translateX(0);
  }

  /* When sidebar is active, maybe dim the main content? */
  .chat-shell::after {
    content: '';
    position: absolute;
    inset: 0;
    background: rgba(0,0,0,0.5);
    z-index: 15;
    opacity: 0;
    pointer-events: none;
    transition: opacity 0.3s;
  }
  
  .chat-sidebar.active ~ .chat-main + .chat-sidebar-backdrop { 
    /* We might need a JS-controlled backdrop or just use the shell::after trick if we can toggle class on shell */
  }

  .chat-input-section {
    padding: 6px 0 2px;
  }
  
  .chat-send {
    padding: 6px 10px;
    font-size: 12px;
  }
  
  .chat-upload {
    padding: 6px 8px;
    font-size: 12px;
  }
}

.link-preview-card {
  display: flex;
  flex-direction: column;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  overflow: hidden;
  margin-top: 8px;
  max-width: 300px;
  background: var(--sidebar-list-bg);
  text-decoration: none;
}

/* Large Screens / Independent Chat Window */
@media (min-width: 600px) {
  :root {
    --sidebar-width: 200px;
  }

  .chat-sidebar-item-name {
    font-size: 14px;
  }
  
  .chat-header-title {
    font-size: 16px;
  }
  
  .chat-message-content {
    font-size: 15px;
    padding: 8px 12px;
  }
  
  .chat-input {
    font-size: 15px;
    padding: 10px 14px;
  }
  
  .chat-send, 
  .chat-upload {
    font-size: 14px;
    padding: 10px 16px;
  }
  
  .chat-sidebar-title {
    font-size: 13px;
  }

  .chat-message-meta {
    font-size: 12px;
  }
}