/* CSS Reset and Base Styles */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

:root {
  --primary-color: #6366f1;
  --primary-hover: #4f46e5;
  --primary-light: #e0e7ff;
  --background: #0f172a;
  --surface: #1e293b;
  --surface-light: #334155;
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --accent: #22d3ee;
  --success: #10b981;
  --border-radius: 12px;
  --transition: all 0.3s ease;
}

body {
  font-family:
    'Segoe UI',
    system-ui,
    -apple-system,
    sans-serif;
  background: var(--background);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  align-items: center;
  padding: 2rem 1rem;
  color: var(--text-primary);
  background-image:
    radial-gradient(ellipse at top, #1e1b4b 0%, transparent 50%),
    radial-gradient(ellipse at bottom, #0c4a6e 0%, transparent 50%);
}

/* Heading Styles */
h1 {
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 700;
  text-align: center;
  margin-bottom: 1rem;
  background: linear-gradient(135deg, var(--primary-color), var(--accent));
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

#myH2 {
  font-size: clamp(1rem, 3vw, 1.25rem);
  font-weight: 500;
  text-align: center;
  margin-bottom: 2rem;
  color: var(--text-secondary);
  min-height: 2em;
  padding: 1rem 1.5rem;
  background: var(--surface);
  border-radius: var(--border-radius);
  border: 1px solid var(--surface-light);
  max-width: 500px;
  width: 100%;
  word-break: break-all;
  transition: var(--transition);
}

#myH2:not(:empty) {
  color: var(--accent);
  border-color: var(--primary-color);
  box-shadow: 0 0 20px rgba(99, 102, 241, 0.2);
}

/* Fieldset Styles */
fieldset {
  background: var(--surface);
  border: 1px solid var(--surface-light);
  border-radius: var(--border-radius);
  padding: 1.5rem;
  margin-bottom: 1.5rem;
  max-width: 400px;
  width: 100%;
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

legend {
  font-weight: 600;
  font-size: 1.1rem;
  padding: 0 0.75rem;
  color: var(--primary-color);
}

/* Label Styles */
label {
  display: flex;
  align-items: center;
  justify-content: space-between;
  cursor: pointer;
  font-size: 0.95rem;
  color: var(--text-secondary);
  padding: 0.5rem 0;
  transition: var(--transition);
}

label:hover {
  color: var(--text-primary);
}

/* Input Number Styles */
input[type='number'] {
  width: 80px;
  padding: 0.5rem 0.75rem;
  font-size: 1rem;
  border: 2px solid var(--surface-light);
  border-radius: 8px;
  background: var(--background);
  color: var(--text-primary);
  text-align: center;
  transition: var(--transition);
}

input[type='number']:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

input[type='number']::-webkit-inner-spin-button,
input[type='number']::-webkit-outer-spin-button {
  opacity: 1;
}

/* Checkbox Styles */
input[type='checkbox'] {
  appearance: none;
  -webkit-appearance: none;
  width: 48px;
  height: 26px;
  background: var(--surface-light);
  border-radius: 13px;
  position: relative;
  cursor: pointer;
  transition: var(--transition);
  flex-shrink: 0;
}

input[type='checkbox']::before {
  content: '';
  position: absolute;
  top: 3px;
  left: 3px;
  width: 20px;
  height: 20px;
  background: var(--text-secondary);
  border-radius: 50%;
  transition: var(--transition);
}

input[type='checkbox']:checked {
  background: var(--primary-color);
}

input[type='checkbox']:checked::before {
  transform: translateX(22px);
  background: white;
}

input[type='checkbox']:focus {
  outline: none;
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.3);
}

/* Button Styles */
button {
  background: linear-gradient(
    135deg,
    var(--primary-color),
    var(--primary-hover)
  );
  color: white;
  font-size: 1.1rem;
  font-weight: 600;
  padding: 1rem 2.5rem;
  border: none;
  border-radius: var(--border-radius);
  cursor: pointer;
  transition: var(--transition);
  box-shadow: 0 4px 15px rgba(99, 102, 241, 0.4);
  position: relative;
  overflow: hidden;
}

button::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: left 0.5s ease;
}

button:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px rgba(99, 102, 241, 0.5);
}

button:hover::before {
  left: 100%;
}

button:active {
  transform: translateY(0);
  box-shadow: 0 2px 10px rgba(99, 102, 241, 0.4);
}

button:focus {
  outline: none;
  box-shadow:
    0 0 0 3px rgba(99, 102, 241, 0.5),
    0 4px 15px rgba(99, 102, 241, 0.4);
}

/* Footer Styles */
footer {
  margin-top: auto;
  padding: 2rem 1rem 1rem;
  text-align: center;
  color: var(--text-secondary);
  font-size: 0.875rem;
}

footer p {
  line-height: 1.8;
}

footer a {
  color: var(--accent);
  text-decoration: none;
  transition: var(--transition);
}

footer a:hover {
  color: var(--primary-color);
  text-decoration: underline;
}

footer br {
  display: block;
  content: '';
  margin-top: 0.5rem;
}

/* Responsive Design */
@media (max-width: 480px) {
  body {
    padding: 1.5rem 1rem;
  }

  fieldset {
    padding: 1rem;
  }

  button {
    width: 100%;
    max-width: 400px;
  }

  label {
    font-size: 0.9rem;
  }

  footer {
    padding: 1.5rem 1rem 1rem;
    font-size: 0.8rem;
  }
}

/* Accessibility - Reduced Motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    transition: none;
  }

  button::before {
    display: none;
  }
}

/* High Contrast Mode Support */
@media (prefers-contrast: high) {
  :root {
    --primary-color: #818cf8;
    --surface: #000;
    --surface-light: #fff;
  }

  fieldset,
  #myH2 {
    border-width: 2px;
  }
}