/* ===== CSS Variables ===== */
:root {
  --primary: #4285F4;
  --primary-hover: #3367d6;
  --bg-primary: #ffffff;
  --bg-secondary: #f8f9fa;
  --bg-tertiary: #e8eaed;
  --text-primary: #202124;
  --text-secondary: #5f6368;
  --text-muted: #9aa0a6;
  --border-color: #dadce0;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
  --radius-sm: 6px;
  --radius-md: 10px;
  --radius-lg: 16px;
  --transition: all 0.2s ease;
  --sidebar-width: 340px;
  --header-height: 60px;
  --danger: #ea4335;
  --success: #34A853;
  --warning: #FBBC04;
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
}

body {
  font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, sans-serif;
  background: var(--bg-secondary);
  color: var(--text-primary);
  height: 100vh;
  overflow: hidden;
  line-height: 1.5;
}

a {
  color: var(--primary);
  text-decoration: none;
}

a:hover {
  text-decoration: underline;
}

/* ===== Header ===== */
.app-header {
  height: var(--header-height);
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 20px;
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  z-index: 100;
  box-shadow: var(--shadow-sm);
}

.header-left {
  display: flex;
  align-items: center;
  gap: 12px;
}

.logo {
  display: flex;
  align-items: center;
}

.app-title {
  font-size: 1.2rem;
  font-weight: 600;
  color: var(--text-primary);
}

.header-right {
  display: flex;
  align-items: center;
  gap: 12px;
}

.user-info {
  font-size: 0.85rem;
  color: var(--text-secondary);
  max-width: 200px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 16px;
  border: none;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  font-weight: 500;
  cursor: pointer;
  transition: var(--transition);
  white-space: nowrap;
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

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

.btn-primary {
  background: var(--primary);
  color: white;
}

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

.btn-outline {
  background: transparent;
  border: 1px solid var(--border-color);
}

.btn-outline:hover {
  background: var(--bg-secondary);
  border-color: var(--text-muted);
}

.btn-sm {
  padding: 5px 10px;
  font-size: 0.8rem;
}

.btn-auth {
  background: var(--primary);
  color: white;
  font-weight: 500;
}

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

.btn-auth.logged-in {
  background: var(--bg-tertiary);
  color: var(--text-primary);
}

.btn-auth.logged-in:hover {
  background: var(--danger);
  color: white;
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 32px;
  height: 32px;
  border: none;
  border-radius: 50%;
  cursor: pointer;
  background: transparent;
  color: var(--text-secondary);
  transition: var(--transition);
  font-size: 1.2rem;
}

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

/* ===== Main Layout ===== */
.app-main {
  display: flex;
  height: calc(100vh - var(--header-height));
  margin-top: var(--header-height);
}

/* ===== Sidebar ===== */
.sidebar {
  width: var(--sidebar-width);
  min-width: var(--sidebar-width);
  background: var(--bg-primary);
  border-right: 1px solid var(--border-color);
  display: flex;
  flex-direction: column;
  overflow: hidden;
}

.sidebar-header {
  padding: 16px;
  border-bottom: 1px solid var(--border-color);
}

.sidebar-header h2 {
  font-size: 1rem;
  font-weight: 600;
  margin-bottom: 12px;
  color: var(--text-primary);
}

.search-box {
  display: flex;
  gap: 6px;
}

.search-box input {
  flex: 1;
  padding: 8px 12px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.85rem;
  outline: none;
  transition: var(--transition);
  background: var(--bg-secondary);
}

.search-box input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(66,133,244,0.15);
  background: var(--bg-primary);
}

.file-list-container {
  flex: 1;
  overflow-y: auto;
  padding: 8px;
}

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

.file-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: var(--transition);
  border: none;
  background: transparent;
  width: 100%;
  text-align: left;
  font-size: 0.875rem;
  color: var(--text-primary);
}

.file-item:hover {
  background: var(--bg-secondary);
}

.file-item.active {
  background: #e8f0fe;
  color: var(--primary);
}

.file-item .file-item-icon {
  flex-shrink: 0;
  width: 20px;
  height: 20px;
  display: flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
}

.file-item.active .file-item-icon {
  color: var(--primary);
}

.file-item .file-item-info {
  flex: 1;
  min-width: 0;
}

.file-item .file-item-name {
  font-weight: 500;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-item .file-item-meta {
  font-size: 0.75rem;
  color: var(--text-muted);
  margin-top: 1px;
}

.sidebar-footer {
  padding: 10px 16px;
  border-top: 1px solid var(--border-color);
  display: flex;
  align-items: center;
  justify-content: space-between;
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* ===== Content Viewer ===== */
.content-viewer {
  flex: 1;
  background: var(--bg-secondary);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: auto;
  min-width: 0;
}

/* Welcome Screen */
.welcome-screen {
  text-align: center;
  padding: 40px 20px;
  max-width: 460px;
}

.welcome-icon {
  margin-bottom: 20px;
}

.welcome-screen h2 {
  font-size: 1.5rem;
  font-weight: 600;
  margin-bottom: 8px;
  color: var(--text-primary);
}

.welcome-screen > p {
  color: var(--text-secondary);
  margin-bottom: 32px;
  font-size: 0.95rem;
}

.welcome-steps {
  display: flex;
  flex-direction: column;
  gap: 16px;
  text-align: left;
}

.step {
  display: flex;
  align-items: center;
  gap: 14px;
  padding: 14px 18px;
  background: var(--bg-primary);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-sm);
  border: 1px solid var(--border-color);
}

.step-number {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-weight: 700;
  font-size: 0.85rem;
  flex-shrink: 0;
}

.step p {
  font-size: 0.9rem;
  color: var(--text-secondary);
}

/* File Preview */
.file-preview {
  display: flex;
  flex-direction: column;
  width: 100%;
  height: 100%;
}

.preview-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px;
  background: var(--bg-primary);
  border-bottom: 1px solid var(--border-color);
}

.preview-file-info {
  display: flex;
  align-items: center;
  gap: 12px;
  min-width: 0;
}

.file-icon {
  flex-shrink: 0;
  color: var(--text-muted);
}

.preview-file-details {
  min-width: 0;
}

.preview-file-details h3 {
  font-size: 1rem;
  font-weight: 600;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.file-meta {
  font-size: 0.8rem;
  color: var(--text-muted);
}

.preview-actions {
  display: flex;
  gap: 6px;
  flex-shrink: 0;
}

.preview-content {
  flex: 1;
  overflow: auto;
  padding: 20px;
}

.content-text {
  background: var(--bg-primary);
  padding: 20px;
  border-radius: var(--radius-md);
  border: 1px solid var(--border-color);
  font-family: 'SF Mono', 'Fira Code', 'Consolas', monospace;
  font-size: 0.85rem;
  line-height: 1.6;
  white-space: pre-wrap;
  word-break: break-word;
  overflow-x: auto;
  min-height: 100px;
  box-shadow: var(--shadow-sm);
}

/* ===== Loading Spinner ===== */
.loading-spinner {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 40px 20px;
  color: var(--text-muted);
  font-size: 0.9rem;
}

.spinner {
  width: 28px;
  height: 28px;
  border: 3px solid var(--border-color);
  border-top-color: var(--primary);
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* ===== Empty State ===== */
.empty-state {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 60px 20px;
  color: var(--text-muted);
  gap: 12px;
}

.empty-state p {
  font-size: 0.9rem;
}

/* ===== Content Error ===== */
.content-error {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 12px;
  padding: 40px;
  color: var(--danger);
}

.content-error p {
  font-size: 0.9rem;
}

/* ===== Toast ===== */
.toast-container {
  position: fixed;
  bottom: 24px;
  right: 24px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  z-index: 1000;
}

.toast {
  padding: 12px 20px;
  border-radius: var(--radius-sm);
  font-size: 0.875rem;
  color: white;
  animation: slideIn 0.3s ease;
  box-shadow: var(--shadow-md);
  max-width: 360px;
}

.toast.success { background: var(--success); }
.toast.error { background: var(--danger); }
.toast.info { background: var(--primary); }

@keyframes slideIn {
  from { transform: translateX(100%); opacity: 0; }
  to { transform: translateX(0); opacity: 1; }
}

/* ===== Config Modal ===== */
.config-modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(0,0,0,0.5);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 200;
  backdrop-filter: blur(4px);
}

.config-modal {
  background: var(--bg-primary);
  border-radius: var(--radius-lg);
  width: 90%;
  max-width: 540px;
  max-height: 90vh;
  overflow-y: auto;
  box-shadow: 0 20px 60px rgba(0,0,0,0.2);
}

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

.modal-header h2 {
  font-size: 1.15rem;
  font-weight: 600;
}

.modal-body {
  padding: 24px;
}

.modal-body > p {
  color: var(--text-secondary);
  margin-bottom: 16px;
  font-size: 0.9rem;
  line-height: 1.6;
}

.config-steps {
  padding-left: 20px;
  margin-bottom: 20px;
}

.config-steps li {
  margin-bottom: 8px;
  font-size: 0.875rem;
  color: var(--text-secondary);
  line-height: 1.5;
}

.config-steps code {
  background: var(--bg-secondary);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 0.8rem;
  color: var(--text-primary);
}

.config-form {
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.config-form label {
  font-size: 0.85rem;
  font-weight: 500;
  color: var(--text-primary);
}

.config-form input {
  padding: 10px 14px;
  border: 1px solid var(--border-color);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  outline: none;
  transition: var(--transition);
}

.config-form input:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 2px rgba(66,133,244,0.15);
}

.config-form .btn {
  align-self: flex-start;
  margin-top: 4px;
}

/* ===== Utility ===== */
.hidden {
  display: none !important;
}

/* ===== Scrollbar ===== */
::-webkit-scrollbar {
  width: 6px;
  height: 6px;
}
::-webkit-scrollbar-track {
  background: transparent;
}
::-webkit-scrollbar-thumb {
  background: var(--border-color);
  border-radius: 3px;
}
::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}

/* ===== Responsive ===== */
@media (max-width: 768px) {
  :root {
    --sidebar-width: 100%;
  }

  .sidebar {
    position: fixed;
    top: var(--header-height);
    left: 0;
    right: 0;
    bottom: 0;
    z-index: 50;
    transform: translateX(-100%);
    transition: transform 0.3s ease;
  }

  .sidebar.open {
    transform: translateX(0);
  }

  .content-viewer {
    width: 100%;
  }

  .app-header {
    padding: 0 12px;
  }

  .app-title {
    font-size: 1rem;
  }

  .welcome-steps {
    gap: 12px;
  }

  .step {
    padding: 12px 14px;
  }

  .config-modal {
    width: 95%;
    border-radius: var(--radius-md);
  }
}