:root {
  --primary: #2c3e50;
  --secondary: #3498db;
  --accent: #1abc9c;
  --light: #ecf0f1;
  --dark: #2c3e50;
  --gray: #7f8c8d;
}

* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
  font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

body {
  background-color: #f9f9f9;
  color: var(--dark);
  line-height: 1.6;
}

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

/* Header */
header {
  background-color: white;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
  position: sticky;
  top: 0;
  z-index: 100;
}

.navbar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 20px 0;
}

.logo {
  font-size: 24px;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
}

.logo span {
  color: var(--secondary);
}

.nav-links {
  display: flex;
  list-style: none;
}

.nav-links li {
  margin-left: 30px;
}

.nav-links a {
  text-decoration: none;
  color: var(--dark);
  font-weight: 500;
  transition: color 0.3s;
}

.nav-links a:hover {
  color: var(--secondary);
}

.btn {
  display: inline-block;
  background-color: var(--secondary);
  color: white;
  padding: 10px 20px;
  border-radius: 5px;
  text-decoration: none;
  font-weight: 600;
  transition: background-color 0.3s;
}

.btn:hover {
  background-color: #2980b9;
}

.btn-download {
  background-color: var(--accent);
}

.btn-download:hover {
  background-color: #16a085;
}

/* Hero Section */
.hero {
  padding: 100px 0;
  background: linear-gradient(135deg, #f5f7fa 0%, #c3cfe2 100%);
  text-align: center;
}

.hero h1 {
  font-size: 3rem;
  margin-bottom: 20px;
  color: var(--primary);
}

.hero p {
  font-size: 1.2rem;
  max-width: 700px;
  margin: 0 auto 30px;
  color: var(--gray);
}

.hero-buttons {
  display: flex;
  justify-content: center;
  gap: 15px;
}

/* Features Section */
.features {
  padding: 80px 0;
  background-color: white;
}

.section-title {
  text-align: center;
  margin-bottom: 50px;
}

.section-title h2 {
  font-size: 2.5rem;
  color: var(--primary);
  margin-bottom: 15px;
}

.section-title p {
  color: var(--gray);
  max-width: 600px;
  margin: 0 auto;
}

.features-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.feature-card {
  background-color: var(--light);
  border-radius: 8px;
  padding: 30px;
  text-align: center;
  transition: transform 0.3s, box-shadow 0.3s;
}

.feature-card:hover {
  transform: translateY(-5px);
  box-shadow: 0 10px 20px rgba(0, 0, 0, 0.1);
}

.feature-icon {
  font-size: 40px;
  color: var(--secondary);
  margin-bottom: 20px;
}

.feature-card h3 {
  margin-bottom: 15px;
  color: var(--primary);
}

.tag {
  background-color: #e0f7fa;
  color: #006064;
  padding: 3px 8px;
  border-radius: 3px;
  font-size: 0.8rem;
}

footer {
  background-color: var(--dark);
  color: white;
  padding: 1.5rem 0;
}

.copyright {
  text-align: center;
  color: #bdc3c7;
  font-size: 0.9rem;
}

/* Search Bar */
.search-container {
  max-width: 600px;
  margin: 0 auto 40px;
  position: relative;
}

.search-bar {
  width: 100%;
  padding: 15px 20px;
  border-radius: 50px;
  border: 1px solid #ddd;
  font-size: 1rem;
  box-shadow: 0 2px 10px rgba(0, 0, 0, 0.1);
}

.search-btn {
  position: absolute;
  right: 5px;
  top: 5px;
  background-color: var(--secondary);
  color: white;
  border: none;
  border-radius: 50px;
  padding: 10px 20px;
  cursor: pointer;
}

/* Theme toggle & logout buttons */
.btn-theme-toggle, .btn-nav-logout {
  background: none;
  border: 1px solid #ddd;
  border-radius: 5px;
  padding: 6px 10px;
  cursor: pointer;
  font-size: 0.9rem;
  color: var(--dark);
  transition: background 0.3s, color 0.3s;
}
.btn-theme-toggle:hover { background: var(--secondary); color: white; border-color: var(--secondary); }
.btn-nav-logout { border-color: #e74c3c; color: #e74c3c; }
.btn-nav-logout:hover { background: #e74c3c; color: white; }
.btn-nav-logout.hidden, #nav-login.hidden { display: none; }

/* Dark Mode */
body.dark {
  --primary: #ecf0f1;
  --secondary: #3498db;
  --dark: #ecf0f1;
  --gray: #bdc3c7;
  background-color: #1a1a2e;
  color: #ecf0f1;
}
body.dark header, body.dark .feature-card, body.dark .section-panel, body.dark .login-card, body.dark .modal {
  background-color: #16213e;
}
body.dark .hero { background: linear-gradient(135deg, #1a1a2e 0%, #16213e 100%); }
body.dark .features { background-color: #1a1a2e; }
body.dark th { background: #0f3460; }
body.dark tr:hover { background: #0f3460; }
body.dark .search-bar, body.dark .form-group input, body.dark .form-group textarea,
body.dark #modal-fields input, body.dark #modal-fields textarea {
  background: #0f3460;
  border-color: #1a3a5c;
  color: #ecf0f1;
}
body.dark .tag { background-color: #0f3460; color: #3498db; }
body.dark .btn-theme-toggle { color: #ecf0f1; border-color: #4a4a6a; }
body.dark .sidebar { background: #0f3460; }
body.dark .dash-header { background: #16213e; }
body.dark .dash-content { background: #1a1a2e; }
body.dark footer { background-color: #0f3460; }

/* Responsive */
@media (max-width: 991px) {
  .hero h1 { font-size: 2.5rem; }
  .section-title h2 { font-size: 2rem; }
  .features-grid { grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); }
}

@media (max-width: 768px) {
  .navbar { flex-direction: column; }
  .nav-links { margin-top: 15px; flex-wrap: wrap; justify-content: center; }
  .nav-links li { margin: 5px 10px; }
  .hero { padding: 60px 0; }
  .hero h1 { font-size: 2rem; }
  .hero p { font-size: 1rem; }
  .section-title h2 { font-size: 1.6rem; }
  .section-title { margin-bottom: 30px; }
  .features { padding: 40px 0; }
  .feature-card { padding: 20px; }
  .feature-icon { font-size: 30px; margin-bottom: 15px; }
  footer { padding: 1.5rem 0; }
  .copyright { font-size: 0.8rem; }
  .copyright p { word-break: break-word; overflow-wrap: break-word; }
}

@media (max-width: 480px) {
  .features-grid { grid-template-columns: 1fr; gap: 15px; }
  .hero h1 { font-size: 1.7rem; }
  .container { width: 95%; padding: 0 10px; }
}