:root {
  /* Color Palette */
  --color-primary: #007bff; /* Blue */
  --color-secondary: #6c757d; /* Gray */
  --color-text-dark: #212529;
  --color-text-light: #f8f9fa;
  --color-bg-main: #ffffff;
  --color-bg-alt: #f8f9fa;
  --color-accent: #17a2b8; /* Teal */

  /* Gradients */
  --gradient-primary: linear-gradient(45deg, #007bff, #6610f2);
  --gradient-accent: linear-gradient(45deg, #17a2b8, #20c997);

  /* Typography */
  --font-primary: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  --font-secondary: 'Roboto', sans-serif;

  /* Spacing */
  --spacing-base: 1rem;
  --border-radius: 0.375rem;
}

/* Reset and base */
body {
  font-family: var(--font-primary);
  color: var(--color-text-dark);
  background-color: var(--color-bg-main);
  line-height: 1.6;
  letter-spacing: 0.02em;
  margin: 0;
  padding-top: 56px; /* for fixed navbar */
}

h1, h2, h3, h4, h5, h6 {
  font-family: var(--font-secondary);
  margin-bottom: 0.5rem;
  font-weight: 600;
  line-height: 1.2;
}

h1 { font-size: 2.5rem; }
h2 { font-size: 2rem; }
h3 { font-size: 1.75rem; }
h4 { font-size: 1.5rem; }
h5 { font-size: 1.25rem; }
h6 { font-size: 1rem; }

/* Links */
a {
  color: var(--color-primary);
  text-decoration: none;
  transition: color 0.3s ease;
}

a:hover, a:focus {
  color: var(--color-accent);
  text-decoration: underline;
}

/* Buttons */
.btn-custom-primary {
  background: var(--gradient-primary);
  color: var(--color-text-light);
  border: none;
  border-radius: var(--border-radius);
  padding: 0.5rem 1.25rem;
  font-weight: 600;
  transition: background 0.3s ease;
}

.btn-custom-primary:hover,
.btn-custom-primary:focus {
  background: var(--gradient-accent);
  color: var(--color-text-light);
  text-decoration: none;
  box-shadow: 0 0 8px var(--color-accent);
}

/* Navbar */
.navbar-custom {
  background-color: var(--color-bg-main);
  box-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.navbar-custom .navbar-nav .nav-link.active {
  color: var(--color-primary);
  font-weight: 700;
  border-bottom: 2px solid var(--color-primary);
}

/* Footer */
.footer {
  background-color: var(--color-bg-alt);
  padding: 3rem 1rem;
  font-size: 0.9rem;
  color: var(--color-text-dark);
}

.footer a {
  color: var(--color-secondary);
}

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

/* Cards */
.card-custom {
  border-radius: var(--border-radius);
  box-shadow: 0 2px 6px rgba(0,0,0,0.1);
  transition: transform 0.3s ease;
}

.card-custom:hover {
  transform: translateY(-5px);
}

/* Responsive Images */
img.responsive-img {
  max-width: 100%;
  height: auto;
  border-radius: var(--border-radius);
}

/* Sections */
.section-alt {
  background-color: var(--color-bg-alt);
  padding: 3rem 1rem;
}

/* Utility classes */
.text-center {
  text-align: center;
}

.mt-5 {
  margin-top: 3rem !important;
}

.mb-5 {
  margin-bottom: 3rem !important;
}

/* Accordion for FAQ */
.accordion-button:not(.collapsed) {
  color: var(--color-primary);
  background-color: var(--color-bg-main);
  box-shadow: inset 0 -1px 0 rgba(0,0,0,.125);
}

.accordion-button::after {
  filter: invert(29%) sepia(98%) saturate(747%) hue-rotate(169deg) brightness(92%) contrast(87%);
}

/* Smooth scrolling */
html {
  scroll-behavior: smooth;
}

/* Loading spinner */
.spinner-border-custom {
  color: var(--color-primary);
}

/* Form validation */
.was-validated .form-control:invalid, .form-control.is-invalid {
  border-color: #dc3545;
  padding-right: calc(1.5em + 0.75rem);
  background-repeat: no-repeat;
  background-position: right calc(0.375em + 0.1875rem) center;
  background-size: calc(0.75em + 0.375rem) calc(0.75em + 0.375rem);
}

.was-validated .form-control:valid, .form-control.is-valid {
  border-color: #198754;
}

/* Custom scrollbar */
::-webkit-scrollbar {
  width: 8px;
}

::-webkit-scrollbar-track {
  background: var(--color-bg-alt);
}

::-webkit-scrollbar-thumb {
  background-color: var(--color-primary);
  border-radius: 10px;
  border: 2px solid var(--color-bg-alt);
}