* {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  /* Color Theme - Dark Gray/Black with Balanced Contrast */
  --primary-color: #6366f1;
  --secondary-color: #8b5cf6;
  --accent-color: #ec4899;
  --error-color: #ef4444;
  --success-color: #10b981;
  --bg-primary: #0f172a;
  --bg-secondary: #1e293b;
  --bg-card: #334155;
  --text-primary: #f1f5f9;
  --text-secondary: #cbd5e1;
  --text-muted: #94a3b8;
  --border-color: #475569;
  --input-bg: #1e293b;
  --input-border: #475569;
  --focus-ring: 0 0 0 3px rgba(99, 102, 241, 0.3);
  
  /* Spacing */
  --spacing-xs: 0.5rem;
  --spacing-sm: 1rem;
  --spacing-md: 1.5rem;
  --spacing-lg: 2rem;
  --spacing-xl: 3rem;
  
  /* Typography */
  --font-size-base: 1rem;
  --font-size-lg: 1.125rem;
  --font-size-xl: 1.5rem;
  --font-size-2xl: 2rem;
  
  /* Border Radius */
  --radius-sm: 0.5rem;
  --radius-md: 1rem;
  --max-width: 700px;
}

body {
  font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
  background: linear-gradient(135deg, var(--bg-primary) 0%, #1a1f3a 100%);
  color: var(--text-primary);
  line-height: 1.6;
  min-height: 100vh;
  padding: var(--spacing-md);
  display: flex;
  justify-content: center;
  align-items: flex-start;
}

.container {
  width: 100%;
  max-width: var(--max-width);
  animation: fadeIn 0.6s ease-in;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Navigation Styles */
nav {
  background: var(--bg-secondary);
  border: 1px solid var(--border-color);
  border-radius: var(--radius-md);
  padding: var(--spacing-md);
  margin-bottom: var(--spacing-xl);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
}

nav ul {
  list-style: none;
  display: flex;
  gap: var(--spacing-md);
  justify-content: center;
  align-items: center;
  flex-wrap: wrap;
  padding: 0;
  margin: 0;
}

nav ul li {
  margin: 0;
}

nav ul li a {
  display: inline-block;
  padding: var(--spacing-sm) var(--spacing-lg);
  color: var(--text-secondary);
  text-decoration: none;
  font-weight: 500;
  font-size: var(--font-size-base);
  border-radius: var(--radius-sm);
  background: var(--bg-card);
  border: 2px solid transparent;
  transition: all 0.3s ease;
  position: relative;
  overflow: hidden;
}

nav ul li a::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, var(--primary-color), var(--secondary-color));
  transition: left 0.3s ease;
  z-index: -1;
}

nav ul li a:hover {
  color: var(--text-primary);
  border-color: var(--primary-color);
  transform: translateY(-2px);
  box-shadow: 0 4px 8px rgba(99, 102, 241, 0.3);
}

nav ul li a:hover::before {
  left: 0;
}

nav ul li a:active {
  transform: translateY(0);
}

/* Active link styling */
nav ul li a[href="contact.html"] {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: var(--text-primary);
  border-color: var(--secondary-color);
}

/* Heading */
h1 {
  font-size: var(--font-size-2xl);
  font-weight: 700;
  margin-bottom: var(--spacing-lg);
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* Form Styles */
form {
  display: grid;
  gap: var(--spacing-md);
  background: var(--bg-secondary);
  padding: var(--spacing-lg);
  border-radius: var(--radius-md);
  box-shadow: 0 4px 6px rgba(0, 0, 0, 0.3);
  border: 1px solid var(--border-color);
}

.field {
  display: grid;
  gap: var(--spacing-xs);
}

label {
  font-weight: 600;
  font-size: var(--font-size-base);
  color: var(--text-primary);
  letter-spacing: 0.3px;
}

input[type="text"],
input[type="email"],
textarea {
  font: inherit;
  padding: var(--spacing-sm);
  background: var(--input-bg);
  color: var(--text-primary);
  border: 2px solid var(--input-border);
  border-radius: var(--radius-sm);
  outline: none;
  transition: all 0.3s ease;
  font-size: var(--font-size-base);
}

input[type="text"]::placeholder,
input[type="email"]::placeholder,
textarea::placeholder {
  color: var(--text-muted);
}

input:focus,
textarea:focus {
  border-color: var(--primary-color);
  box-shadow: var(--focus-ring);
  background: var(--bg-card);
}

textarea {
  min-height: 140px;
  resize: vertical;
  font-family: inherit;
}

/* Error Messages */
.error {
  color: var(--error-color);
  font-size: 0.9rem;
  display: none;
  margin-top: 4px;
  font-weight: 500;
}

.error:not(:empty) {
  display: block;
}

/* Success Message */
.success {
  color: var(--success-color);
  font-weight: 600;
  display: none;
  padding: var(--spacing-md);
  border-radius: var(--radius-sm);
  background: rgba(16, 185, 129, 0.1);
  border: 2px solid rgba(16, 185, 129, 0.3);
  margin-bottom: var(--spacing-lg);
  box-shadow: 0 2px 8px rgba(16, 185, 129, 0.2);
}

.success:not([hidden]) {
  display: block;
}

/* Form Actions */
.actions {
  display: flex;
  gap: var(--spacing-md);
  align-items: center;
  margin-top: var(--spacing-sm);
}

button[type="submit"] {
  background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
  color: var(--text-primary);
  border: none;
  padding: var(--spacing-sm) var(--spacing-lg);
  border-radius: var(--radius-sm);
  cursor: pointer;
  font-weight: 600;
  font-size: var(--font-size-base);
  transition: all 0.3s ease;
  box-shadow: 0 4px 6px rgba(99, 102, 241, 0.3);
  letter-spacing: 0.3px;
}

button[type="submit"]:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 12px rgba(99, 102, 241, 0.4);
}

button[type="submit"]:focus {
  outline: none;
  box-shadow: var(--focus-ring), 0 4px 6px rgba(99, 102, 241, 0.3);
}

button[type="submit"]:active {
  transform: translateY(0);
}

button[type="submit"]:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none;
}

/* Accessibility */
.visually-hidden {
  position: absolute !important;
  height: 1px;
  width: 1px;
  overflow: hidden;
  clip: rect(1px, 1px, 1px, 1px);
  white-space: nowrap;
}

/* Input validation states */
input[aria-invalid="true"],
textarea[aria-invalid="true"] {
  border-color: var(--error-color);
  background: rgba(239, 68, 68, 0.05);
}

/* Responsive Design */
@media (max-width: 768px) {
  :root {
    --font-size-base: 0.95rem;
    --font-size-lg: 1rem;
    --font-size-xl: 1.25rem;
    --font-size-2xl: 1.75rem;
    --spacing-lg: 1.5rem;
    --spacing-xl: 2rem;
  }
  
  body {
    padding: var(--spacing-sm);
  }
  
  nav {
    padding: var(--spacing-sm);
  }
  
  nav ul {
    gap: var(--spacing-sm);
  }
  
  nav ul li a {
    padding: var(--spacing-xs) var(--spacing-md);
    font-size: 0.9rem;
  }
  
  form {
    padding: var(--spacing-md);
  }
}

@media (max-width: 480px) {
  :root {
    --font-size-base: 0.9rem;
    --font-size-lg: 0.95rem;
    --font-size-xl: 1.125rem;
    --font-size-2xl: 1.5rem;
    --spacing-md: 1rem;
    --spacing-lg: 1.25rem;
  }
  
  body {
    padding: var(--spacing-xs);
  }
  
  nav ul {
    flex-direction: column;
    gap: var(--spacing-xs);
  }
  
  nav ul li {
    width: 100%;
  }
  
  nav ul li a {
    width: 100%;
    text-align: center;
    padding: var(--spacing-xs) var(--spacing-sm);
  }
  
  form {
    padding: var(--spacing-sm);
  }
  
  .actions {
    flex-direction: column;
    align-items: stretch;
  }
  
  button[type="submit"] {
    width: 100%;
  }
}