:root {
  --bg-main: #0f172a;
  --bg-card: #1e293b;
  --bg-input: #334155;
  --text-main: #f8fafc;
  --text-muted: #94a3b8;
  --primary: #6366f1;
  --primary-hover: #4f46e5;
  --success: #22c55e;
  --warning: #f59e0b;
  --danger: #ef4444;
  --border: #334155;
  --radius: 12px;
}

* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  font-family: 'Inter', system-ui, -apple-system, sans-serif;
}

body {
  background-color: var(--bg-main);
  color: var(--text-main);
  display: flex;
  min-height: 100vh;
}

/* Sidebar Responsive */
aside {
  width: 260px;
  background-color: var(--bg-card);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  position: fixed;
  height: 100vh;
  z-index: 100;
  transition: transform 0.3s ease;
}

.logo-area {
  padding: 24px;
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--primary);
  border-bottom: 1px solid var(--border);
  display: flex;
  align-items: center;
  gap: 10px;
}

.nav-links {
  list-style: none;
  padding: 20px 12px;
  overflow-y: auto;
  flex-grow: 1;
}

.nav-links li a {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 16px;
  color: var(--text-muted);
  text-decoration: none;
  font-weight: 500;
  border-radius: 8px;
  transition: all 0.2s;
  margin-bottom: 4px;
}

.nav-links li a:hover, .nav-links li a.active {
  background-color: var(--primary);
  color: #fff;
}

/* Main Content Wrapper */
main {
  margin-left: 260px;
  flex-grow: 1;
  padding: 30px;
  max-width: calc(100vw - 260px);
}

.header-top {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 30px;
}

.header-top h1 {
  font-size: 1.8rem;
  font-weight: 700;
}

/* Grid System & Cards */
.grid-cards {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
  gap: 20px;
  margin-bottom: 30px;
}

.card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  padding: 20px;
  position: relative;
  box-shadow: 0 4px 6px -1px rgba(0,0,0,0.1);
}

.card h3 {
  font-size: 0.9rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 0.5px;
  margin-bottom: 8px;
}

.card .value {
  font-size: 1.8rem;
  font-weight: 700;
}

.card.success { border-left: 4px solid var(--success); }
.card.warning { border-left: 4px solid var(--warning); }
.card.danger { border-left: 4px solid var(--danger); }
.card.primary { border-left: 4px solid var(--primary); }

/* Tables */
.table-container {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  overflow-x: auto;
  margin-bottom: 30px;
}

table {
  width: 100%;
  border-collapse: collapse;
  text-align: left;
  font-size: 0.95rem;
}

th, td {
  padding: 14px 20px;
  border-bottom: 1px solid var(--border);
}

th {
  background-color: rgba(255,255,255,0.02);
  color: var(--text-muted);
  font-weight: 600;
}

tr:last-child td {
  border-bottom: none;
}

/* Forms & Buttons */
.form-group {
  margin-bottom: 20px;
}

label {
  display: block;
  font-size: 0.9rem;
  font-weight: 500;
  margin-bottom: 8px;
  color: var(--text-muted);
}

input, select, textarea {
  width: 100%;
  padding: 12px 16px;
  background-color: var(--bg-input);
  border: 1px solid var(--border);
  border-radius: 8px;
  color: var(--text-main);
  font-size: 1rem;
}

input:focus, select:focus, textarea:focus {
  outline: none;
  border-color: var(--primary);
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background-color: var(--primary);
  color: #fff;
  padding: 12px 24px;
  border: none;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: background-color 0.2s;
  text-decoration: none;
}

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

.btn-success { background-color: var(--success); }
.btn-success:hover { background-color: #16a34a; }
.btn-danger { background-color: var(--danger); }
.btn-danger:hover { background-color: #dc2626; }

/* Responsive Media Query */
@media(max-width: 768px) {
  aside {
    transform: translateX(-100%);
  }
  main {
    margin-left: 0;
    max-width: 100vw;
    padding: 15px;
  }
}