:root {
  --bg: #f8f9fa;
  --text: #212529;
  --nav-bg: rgba(255, 255, 255, 0.85);
  --card-bg: #fff;
  --primary: #007bff;
  --secondary: #6c757d;
  --success: #28a745;
  --danger: #dc3545;
  --warning: #ffc107;
  --info: #17a2b8;
  --border: #dee2e6;
  --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
  --radius: 12px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
  --font-mono: 'JetBrains Mono', 'Courier New', monospace;
  --font-serif: Georgia, 'Times New Roman', serif;
  --font-gothic: 'Franklin Gothic Medium', sans-serif;
  --space: 1rem;
}

body.dark, body.dark-mode {
  --bg: #0f172a;
  --text: #f1f5f9;
  --nav-bg: rgba(30, 41, 59, 0.85);
  --card-bg: #1e293b;
  --primary: #3b82f6;
  --secondary: #94a3b8;
  --success: #22c55e;
  --danger: #ef4444;
  --warning: #f59e0b;
  --info: #06b6d4;
  --border: #334155;
  --shadow: 0 10px 15px -3px rgba(0,0,0,0.3);
}

@media (prefers-color-scheme: dark) {
  body:not(.light):not(.dark-mode) {
    --bg: #0f172a;
    --text: #f1f5f9;
    --nav-bg: rgba(30, 41, 59, 0.85);
    --card-bg: #1e293b;
    --primary: #3b82f6;
    --border: #334155;
    --shadow: 0 10px 15px -3px rgba(0,0,0,0.3);
  }
}

*, *::before, *::after { box-sizing: border-box; }

body {
  margin: 0;
  background: var(--bg);
  color: var(--text);
  font-family: var(--font);
  line-height: 1.6;
  transition: background-color 0.3s, color 0.3s;
}

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

/* ─── Typography ─── */
h1, h2, h3, h4, h5 { margin-bottom: 0.75rem; font-weight: 700; color: var(--text); }
h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.5rem; }
p { margin-bottom: 1rem; line-height: 1.7; }

.font-mono { font-family: var(--font-mono); }
.font-serif { font-family: var(--font-serif); }
.font-gothic { font-family: var(--font-gothic); }

/* ─── Navigation ─── */
.navbar-con {
  background: var(--nav-bg);
  backdrop-filter: blur(10px);
  border-bottom: 1px solid var(--border);
  position: fixed; top: 0; left: 0; width: 100%; height: 64px;
  display: flex; align-items: center; padding: 0 2rem; z-index: 1000;
}
.navbar-con ul { list-style: none; margin: 0; padding: 0; display: flex; gap: 1.5rem; }
.navbar-con a { color: var(--text); font-weight: 500; font-size: 0.9rem; }
.navbar-con a:hover { color: var(--primary); text-decoration: none; }

/* ─── Container ─── */
.container {
  max-width: 1100px; margin: 100px auto 4rem; padding: 0 1.5rem;
}

/* ─── Grid ─── */
.grid { display: grid; gap: 1.5rem; margin-bottom: 2rem; }
.grid-2 { grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); }
.grid-3 { grid-template-columns: repeat(auto-fit, minmax(280px, 1fr)); }
.grid-4 { grid-template-columns: repeat(auto-fit, minmax(240px, 1fr)); }

.row { display: flex; flex-wrap: wrap; gap: 1.5rem; margin-bottom: 2rem; }
.col { flex: 1; min-width: 280px; }
.col-1 { flex: 0 0 8.33%; }
.col-2 { flex: 0 0 16.66%; }
.col-3 { flex: 0 0 25%; }
.col-4 { flex: 0 0 33.33%; }
.col-6 { flex: 0 0 50%; }
.col-8 { flex: 0 0 66.66%; }
.col-12 { flex: 0 0 100%; }

/* ─── Card ─── */
.card {
  background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 2rem; box-shadow: var(--shadow); transition: transform 0.2s, box-shadow 0.2s;
}
.card:hover { transform: translateY(-4px); box-shadow: 0 20px 25px -5px rgba(0,0,0,0.1); }
.card-flat { box-shadow: none; border-color: var(--border); }
.card-flat:hover { transform: none; box-shadow: none; }

/* ─── Buttons ─── */
.btn {
  display: inline-flex; align-items: center; justify-content: center; gap: 0.5rem;
  padding: 0.65rem 1.4rem; border-radius: 8px; font-weight: 600; font-size: 0.9rem;
  border: 2px solid transparent; cursor: pointer; text-decoration: none;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  line-height: 1.4;
}
.btn:hover { transform: translateY(-1px); text-decoration: none; }
.btn:active { transform: scale(0.97); }

.btn-primary { background: var(--primary); color: #fff; border-color: var(--primary); }
.btn-primary:hover { filter: brightness(1.1); }

.btn-secondary { background: var(--secondary); color: #fff; border-color: var(--secondary); }
.btn-secondary:hover { filter: brightness(1.15); }

.btn-outline { background: transparent; color: var(--primary); border-color: var(--primary); }
.btn-outline:hover { background: var(--primary); color: #fff; }

.btn-ghost { background: transparent; color: var(--text); border-color: transparent; }
.btn-ghost:hover { background: rgba(128,128,128,0.1); }

.btn-danger { background: var(--danger); color: #fff; border-color: var(--danger); }
.btn-danger:hover { filter: brightness(1.1); }

.btn-sm { padding: 0.4rem 1rem; font-size: 0.8rem; }
.btn-lg { padding: 0.9rem 2rem; font-size: 1.05rem; }

/* ─── Alerts ─── */
.alert {
  padding: 1rem 1.5rem; border-radius: 8px; margin-bottom: 1rem;
  border-left: 4px solid transparent; font-size: 0.9rem;
}
.alert-success { background: rgba(40,167,69,0.1); color: var(--success); border-left-color: var(--success); }
.alert-error   { background: rgba(220,53,69,0.1); color: var(--danger); border-left-color: var(--danger); }
.alert-info    { background: rgba(23,162,184,0.1); color: var(--info); border-left-color: var(--info); }
.alert-warning { background: rgba(255,193,7,0.1); color: #b8860b; border-left-color: var(--warning); }

/* ─── Forms ─── */
.form-group { margin-bottom: 1.25rem; }
.form-label { display: block; margin-bottom: 0.4rem; font-weight: 600; font-size: 0.85rem; }
.input, .select, .textarea {
  width: 100%; padding: 0.7rem 1rem; border-radius: 8px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
  font-family: inherit; font-size: 0.9rem; transition: border-color 0.2s, box-shadow 0.2s;
}
.input:focus, .select:focus, .textarea:focus {
  outline: none; border-color: var(--primary); box-shadow: 0 0 0 3px rgba(0,123,255,0.2);
}
.textarea { resize: vertical; min-height: 100px; }
.select { appearance: none; background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23666' d='M6 8L1 3h10z'/%3E%3C/svg%3E"); background-repeat: no-repeat; background-position: right 1rem center; padding-right: 2.5rem; }

/* ─── Tables ─── */
.table { width: 100%; border-collapse: collapse; margin-bottom: 1.5rem; }
.table th, .table td {
  padding: 0.75rem 1rem; text-align: left; border-bottom: 1px solid var(--border); font-size: 0.9rem;
}
.table th { font-weight: 700; background: var(--card-bg); }
.table-striped tr:nth-child(even) { background: rgba(128,128,128,0.04); }
.table-hover tr:hover { background: rgba(0,123,255,0.05); }
.table-bordered th, .table-bordered td { border: 1px solid var(--border); }

/* ─── Badges ─── */
.badge {
  display: inline-block; padding: 0.2rem 0.65rem; font-size: 0.7rem; font-weight: 700;
  border-radius: 20px; text-transform: uppercase; letter-spacing: 0.03em;
}
.badge-primary { background: var(--primary); color: #fff; }
.badge-secondary { background: var(--secondary); color: #fff; }
.badge-success { background: var(--success); color: #fff; }
.badge-danger { background: var(--danger); color: #fff; }
.badge-warning { background: var(--warning); color: #212529; }

/* ─── Images ─── */
.img-fluid { max-width: 100%; height: auto; display: block; }
.img-round { border-radius: 50%; }
.img-shadow { box-shadow: var(--shadow); }
.img-bordered { border: 2px solid var(--border); border-radius: var(--radius); }

/* ─── Code ─── */
code, .code {
  font-family: var(--font-mono); font-size: 0.85em;
  background: rgba(128,128,128,0.1); padding: 0.15rem 0.4rem; border-radius: 4px;
}
pre, .pre {
  font-family: var(--font-mono); font-size: 0.85rem;
  background: var(--card-bg); border: 1px solid var(--border); border-radius: var(--radius);
  padding: 1.25rem; overflow-x: auto; line-height: 1.6; margin-bottom: 1rem;
}
pre code { background: none; padding: 0; border-radius: 0; }

/* ─── Spinner ─── */
.spinner {
  display: inline-block; width: 24px; height: 24px; border: 3px solid var(--border);
  border-top-color: var(--primary); border-radius: 50%; animation: spin 0.7s linear infinite;
}
.spinner-lg { width: 40px; height: 40px; border-width: 4px; }
@keyframes spin { to { transform: rotate(360deg); } }

/* ─── Flex Utilities ─── */
.flex { display: flex; }
.flex-col { flex-direction: column; }
.flex-wrap { flex-wrap: wrap; }
.flex-1 { flex: 1; }
.items-start { align-items: flex-start; }
.items-center { align-items: center; }
.items-end { align-items: flex-end; }
.justify-start { justify-content: flex-start; }
.justify-center { justify-content: center; }
.justify-between { justify-content: space-between; }
.justify-end { justify-content: flex-end; }
.gap-0 { gap: 0; }
.gap-1 { gap: 0.5rem; }
.gap-2 { gap: 1rem; }
.gap-3 { gap: 1.5rem; }
.gap-4 { gap: 2rem; }

/* ─── Spacing ─── */
.m-0 { margin: 0; } .p-0 { padding: 0; }
.m-1 { margin: 0.5rem; } .p-1 { padding: 0.5rem; }
.m-2 { margin: 1rem; } .p-2 { padding: 1rem; }
.m-3 { margin: 1.5rem; } .p-3 { padding: 1.5rem; }
.m-4 { margin: 2rem; } .p-4 { padding: 2rem; }
.mt-1 { margin-top: 0.5rem; } .mb-1 { margin-bottom: 0.5rem; }
.mt-2 { margin-top: 1rem; } .mb-2 { margin-bottom: 1rem; }
.mt-3 { margin-top: 1.5rem; } .mb-3 { margin-bottom: 1.5rem; }
.mt-4 { margin-top: 2rem; } .mb-4 { margin-bottom: 2rem; }
.ml-1 { margin-left: 0.5rem; } .mr-1 { margin-right: 0.5rem; }
.ml-2 { margin-left: 1rem; } .mr-2 { margin-right: 1rem; }
.pt-1 { padding-top: 0.5rem; } .pb-1 { padding-bottom: 0.5rem; }
.pt-2 { padding-top: 1rem; } .pb-2 { padding-bottom: 1rem; }
.pt-3 { padding-top: 1.5rem; } .pb-3 { padding-bottom: 1.5rem; }
.pt-4 { padding-top: 2rem; } .pb-4 { padding-bottom: 2rem; }

/* ─── Text Utilities ─── */
.text-center { text-align: center; }
.text-right { text-align: right; }
.text-left { text-align: left; }
.text-sm { font-size: 0.85rem; }
.text-lg { font-size: 1.15rem; }
.text-xl { font-size: 1.4rem; }
.text-muted { opacity: 0.65; }
.text-primary { color: var(--primary); }
.text-success { color: var(--success); }
.text-danger { color: var(--danger); }
.text-bold { font-weight: 700; }

/* ─── Display Utilities ─── */
.hidden { display: none !important; }
.block { display: block; }
.inline-block { display: inline-block; }
.w-100 { width: 100%; }

/* ─── Dividers ─── */
hr { border: none; border-top: 1px solid var(--border); margin: 2rem 0; }

/* ─── List Utilities ─── */
.list-unstyled { list-style: none; padding: 0; }
.list-inline { list-style: none; padding: 0; display: flex; gap: 1rem; }

/* ─── Skeleton Loading ─── */
.skeleton {
  background: linear-gradient(90deg, var(--border) 25%, transparent 50%, var(--border) 75%);
  background-size: 200% 100%; animation: shimmer 1.5s infinite;
  border-radius: 6px; height: 1em;
}
@keyframes shimmer { 0% { background-position: 200% 0; } 100% { background-position: -200% 0; } }

/* ─── Responsive ─── */
@media (max-width: 768px) {
  h1 { font-size: 2rem; } h2 { font-size: 1.6rem; }
  .container { padding: 0 1rem; }
  .grid-2, .grid-3, .grid-4 { grid-template-columns: 1fr; }
  .row { flex-direction: column; }
  .col { min-width: 100%; }
  .navbar-con { padding: 0 1rem; }
  .navbar-con ul { gap: 1rem; }
  .hide-mobile { display: none !important; }
  .col-1, .col-2, .col-3, .col-4, .col-6, .col-8, .col-12 { flex: 0 0 100%; }
}