/* Base styles */
body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  margin: 0;
  padding: 0;
  background-color: #f5f5f5;
  color: #333;
  line-height: 1.6;
}

.container {
  width: 90%;
  max-width: 1200px;
  margin: 0 auto;
  padding: 20px;
}

/* Header */
header {
  background: linear-gradient(90deg, #0068c9 0%, #0056a7 100%);
  color: white;
  padding: 1rem 0;
  box-shadow: 0 2px 5px rgba(0,0,0,0.1);
}

header .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.logo {
  font-size: 1.5rem;
  font-weight: bold;
}

nav ul {
  display: flex;
  list-style: none;
  margin: 0;
  padding: 0;
}

nav ul li {
  margin-left: 20px;
}

nav ul li a {
  color: white;
  text-decoration: none;
  transition: opacity 0.3s;
}

nav ul li a:hover {
  opacity: 0.8;
}

/* Main content */
main {
  padding: 2rem 0;
}

h1, h2, h3 {
  color: #0068c9;
}

/* Modern Glassmorphism Card Effect */
.card, .group-card, .stat-card {
  background: rgba(255,255,255,0.85);
  border-radius: 16px;
  box-shadow: 0 8px 32px 0 rgba(31, 38, 135, 0.10);
  backdrop-filter: blur(6px);
  border: 1px solid rgba(255,255,255,0.18);
  transition: transform 0.3s, box-shadow 0.3s;
}
.card:hover, .group-card:hover, .stat-card:hover {
  transform: translateY(-6px) scale(1.01);
  box-shadow: 0 12px 32px 0 rgba(31, 38, 135, 0.18);
}

.card h3 {
  margin-top: 0;
  border-bottom: 1px solid #eee;
  padding-bottom: 10px;
}

/* Dashboard Stat Cards */
.dashboard {
  gap: 32px;
}
.stat-card {
  padding: 32px 20px;
  min-width: 220px;
  border-left: 6px solid #0068c9;
  background: linear-gradient(135deg, #e0e7ff 0%, #fff 100%);
}
.stat-value {
  font-size: 2.5rem;
  color: #0056a7;
  margin-bottom: 8px;
}
.stat-label {
  font-size: 1.1rem;
  color: #666;
}

/* Tab Buttons */
.tab-buttons {
  background: #f2f6fc;
  border-radius: 8px 8px 0 0;
  overflow: hidden;
}
.tab-button {
  flex: 1;
  font-size: 1.1rem;
  padding: 14px 0;
  background: none;
  border: none;
  color: #0068c9;
  font-weight: 500;
  border-bottom: 3px solid transparent;
  transition: background 0.2s, border-bottom 0.2s;
}
.tab-button.active {
  background: #e0e7ff;
  border-bottom: 3px solid #0068c9;
  color: #003366;
}

/* Table Modern Look */
table {
  border-radius: 8px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 2px 8px rgba(0,0,0,0.04);
}
th, td {
  border: none;
  padding: 14px 12px;
}
th {
  background: #e0e7ff;
  color: #003366;
  font-weight: 600;
}
tr:nth-child(even) {
  background: #f7faff;
}

/* Buttons */
.btn {
  display: inline-block;
  padding: 8px 16px;
  background: linear-gradient(90deg, #0068c9 0%, #0056a7 100%);
  color: white;
  border: none;
  border-radius: 6px;
  cursor: pointer;
  text-decoration: none;
  font-size: 14px;
  transition: background-color 0.3s;
  letter-spacing: 0.5px;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}

.btn:hover {
  background-color: #0056a7;
}

.btn-sm {
  padding: 4px 8px;
  font-size: 12px;
}

.btn-danger {
  background: linear-gradient(90deg, #dc3545 0%, #bd2130 100%);
}

.btn-danger:hover {
  background-color: #bd2130;
}

/* Form Modern Look */
input, textarea {
  border: 1.5px solid #e0e7ff;
  border-radius: 6px;
  padding: 10px;
  font-size: 1rem;
  margin-bottom: 12px;
  width: 100%;
  background: #f7faff;
  transition: border 0.2s;
}
input:focus, textarea:focus {
  border-color: #0068c9;
  outline: none;
}
label {
  font-weight: 500;
  color: #003366;
  margin-bottom: 4px;
  display: block;
}

/* Footer Modern */
footer {
  background: linear-gradient(90deg, #003366 0%, #0068c9 100%);
  color: #fff;
  border-top-left-radius: 16px;
  border-top-right-radius: 16px;
  padding: 1rem 0;
  text-align: center;
  margin-top: 2rem;
}

/* Thêm style cho bảng, form, tab, responsive, lỗi, login, 404 */
.table-modern {
  width: 100%;
  border-radius: 12px;
  overflow: hidden;
  background: #fff;
  box-shadow: 0 2px 12px rgba(0,104,201,0.07);
  margin-bottom: 1.5rem;
}
.table-modern th, .table-modern td {
  border: none;
  padding: 14px 12px;
}
.table-modern th {
  background: #e0e7ff;
  color: #003366;
  font-weight: 600;
}
.table-modern tr:nth-child(even) {
  background: #f7faff;
}

/* Tab buttons */
.tab-buttons .tab-button {
  border-radius: 8px 8px 0 0;
  background: #f2f6fc;
  color: #0068c9;
  border: none;
  border-bottom: 3px solid transparent;
  padding: 14px 18px;
  font-size: 1.1rem;
  font-weight: 600;
  transition: background 0.2s, border-bottom 0.2s;
}
.tab-buttons .tab-button.active {
  background: #e0e7ff;
  border-bottom: 3px solid #00c6fb;
  color: #003366;
}

/* Responsive */
@media (max-width: 700px) {
  .admin-title { font-size: 1.5rem; }
  .dashboard { grid-template-columns: 1fr; gap: 12px; }
  .tab-button { font-size: 1rem; padding: 10px 0; }
  .card, .stat-card { padding: 10px 4px; }
  .login-card, .notfound-card { padding: 18px 6px; }
}

/* Error message */
.error-message {
  color: #dc3545;
  font-weight: 600;
  margin: 10px 0 18px 0;
  text-align: center;
}

/* Login/404 card (for fallback) */
.login-card, .notfound-card {
  background: rgba(255,255,255,0.97);
  border-radius: 18px;
  box-shadow: 0 8px 32px 0 rgba(31,38,135,0.18);
  padding: 40px 32px 32px 32px;
  max-width: 350px;
  width: 100%;
  text-align: center;
  margin: 40px auto;
}
.login-card h2, .notfound-card h1 {
  background: linear-gradient(90deg,#0068c9,#00c6fb 70%);
  color: transparent;
  -webkit-background-clip: text;
  background-clip: text;
}
.login-card h2 { font-size: 2rem; font-weight: 800; margin-bottom: 1.5rem; }
.notfound-card h1 { font-size: 4rem; font-weight: 900; margin-bottom: 0.5rem; }

/* Responsive improvements for mobile */
@media (max-width: 600px) {
  .container {
    width: 98%;
    padding: 6px;
  }
  .dashboard {
    grid-template-columns: 1fr;
    gap: 16px;
  }
  .card, .group-card, .stat-card {
    padding: 12px 6px;
    border-radius: 10px;
    font-size: 0.98rem;
  }
  .tab-buttons {
    flex-direction: column;
  }
  .tab-button {
    font-size: 1rem;
    padding: 10px 0;
  }
  table, th, td {
    font-size: 0.95rem;
    padding: 8px 4px;
  }
  h1, h2 {
    font-size: 1.3rem;
  }
  .stat-value {
    font-size: 1.5rem;
  }
}

/* Hide scrollbars on mobile for cards */
.card, .group-card, .stat-card {
  -webkit-overflow-scrolling: touch;
  overflow-x: auto;
}

/* Đẹp cho form đăng nhập hệ thống (user-login) */
.login-card {
  background: rgba(255,255,255,0.98);
  border-radius: 18px;
  box-shadow: 0 8px 32px 0 rgba(31,38,135,0.18);
  padding: 36px 28px 28px 28px;
  max-width: 420px;
  width: 100%;
  margin: 40px auto;
  border: 1.5px solid #e0e7ff;
}
.login-card h2 {
  font-size: 1.7rem;
  font-weight: 800;
  margin-bottom: 1.5rem;
  background: linear-gradient(90deg,#0068c9,#00c6fb 70%);
  color: transparent;
  -webkit-background-clip: text;
  background-clip: text;
  text-align: center;
}
.login-card label {
  font-weight: 600;
  color: #0068c9;
  margin-bottom: 4px;
  display: block;
}
.login-card input {
  width: 100%;
  padding: 10px;
  margin-bottom: 16px;
  border-radius: 8px;
  border: 1.5px solid #e0e7ff;
  font-size: 1rem;
  background: #f7faff;
  transition: border 0.2s;
}
.login-card input:focus {
  border-color: #0068c9;
  outline: none;
}
.login-card button {
  width: 100%;
  padding: 12px;
  border-radius: 8px;
  background: linear-gradient(90deg,#0068c9,#00c6fb 70%);
  color: #fff;
  font-weight: 700;
  font-size: 1.1rem;
  border: none;
  cursor: pointer;
  transition: background 0.2s;
}
.login-card button:hover {
  background: linear-gradient(90deg,#0056a7,#00b6e6 70%);
}
.login-result {
  margin-top: 18px;
  text-align: center;
  font-weight: 600;
  color: #dc3545;
}