/* ==========================================
   1. CORE VARIABLES & BASE TYPOGRAPHY
   ========================================== */
:root {
  /* Color Palette */
  --bg-main: #ffffff;
  --bg-surface: #f8fafc;
  --bg-hover: #f1f5f9;
  
  --text-primary: #0f172a;   /* Dark navy/slate for high legibility */
  --text-secondary: #475569; /* Subheadings, metadata */
  --text-muted: #64748b;     /* Placeholders, secondary labels */

  --primary: #0284c7;        /* Enterprise tech blue */
  --primary-hover: #0369a1;
  
  --border-light: #e2e8f0;
  --border-strong: #cbd5e1;

  /* Fonts & Radius */
  --font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  --radius-sm: 4px;
  --radius-md: 6px;
  --shadow-sm: 0 1px 2px 0 rgba(0, 0, 0, 0.05);
}

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

body {
  font-family: var(--font-family);
  background-color: var(--bg-main);
  color: var(--text-primary);
  line-height: 1.6;
  font-size: 16px;
}

h1 {
  font-size: 28px;
  font-weight: 700;
  color: var(--text-primary);
}

/* ==========================================
   2. MAIN APPLICATION LAYOUT
   ========================================== */
.app-container {
  display: grid;
  grid-template-rows: 64px 1fr;
  height: 100vh;
}

.top-navbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 0 24px;
  background-color: var(--bg-main);
  border-bottom: 1px solid var(--border-light);
}

.main-layout {
  display: grid;
  grid-template-columns: 260px 1fr 300px;
  height: calc(100vh - 64px);
}

/* ==========================================
   3. NAVIGATION & SIDE PANELS
   ========================================== */
.left-sidebar {
  background-color: var(--bg-surface);
  border-right: 1px solid var(--border-light);
  padding: 24px 16px;
  overflow-y: auto;
}

.content-area {
  padding: 32px 40px;
  overflow-y: auto;
  background-color: var(--bg-main);
}

.right-filters {
  background-color: var(--bg-surface);
  border-left: 1px solid var(--border-light);
  padding: 24px 20px;
  overflow-y: auto;
}

.nav-group-title {
  font-size: 13px;
  font-weight: 700;
  text-transform: uppercase;
  color: var(--text-muted);
  letter-spacing: 0.05em;
  margin-bottom: 12px;
}

.nav-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 10px 14px;
  font-size: 15px;
  color: var(--text-secondary);
  text-decoration: none;
  border-radius: var(--radius-md);
  font-weight: 500;
  transition: background-color 0.15s ease, color 0.15s ease;
}

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

.nav-item.active {
  background-color: var(--bg-hover);
  color: var(--primary);
  font-weight: 600;
}

/* ==========================================
   4. DATA TABLES (FOLDERS & DOCUMENTS)
   ========================================== */
.header-actions {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 24px;
}

.wiki-table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
}

.wiki-table th {
  background-color: var(--bg-surface);
  color: var(--text-secondary);
  font-weight: 600;
  font-size: 14px;
  padding: 14px 18px;
  border-bottom: 1px solid var(--border-light);
}

.wiki-table td {
  padding: 16px 18px;
  border-bottom: 1px solid var(--border-light);
  color: var(--text-primary);
  font-size: 15px;
}

.wiki-table tbody tr:hover {
  background-color: var(--bg-surface);
  cursor: pointer;
}

/* ==========================================
   5. FORM CONTROLS & BUTTONS
   ========================================== */
.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background-color: var(--primary);
  color: #ffffff;
  border: none;
  padding: 10px 18px;
  font-size: 14px;
  border-radius: var(--radius-md);
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.15s ease;
}

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

.form-control {
  width: 100%;
  padding: 10px 14px;
  font-size: 15px;
  border: 1px solid var(--border-strong);
  border-radius: var(--radius-md);
  background-color: var(--bg-main);
  color: var(--text-primary);
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.form-control:focus {
  outline: none;
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(2, 132, 199, 0.15);
}