/* Skip link */
.skip-link {
  position: absolute;
  top: -100%;
  left: var(--space-md);
  z-index: 9999;
  padding: var(--space-sm) var(--space-md);
  background: var(--color-primary);
  color: var(--color-text-inverse);
  border-radius: var(--radius-sm);
  text-decoration: none;
  font-weight: 600;
}

.skip-link:focus {
  top: var(--space-sm);
}

/* Visually hidden (accessible to screen readers) */
.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* Container */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--space-md);
}

/* Flow spacing */
.flow > * + * {
  margin-block-start: var(--space-md);
}

.flow-lg > * + * {
  margin-block-start: var(--space-lg);
}

/* Card */
.card {
  background: var(--color-bg-card);
  border: 1px solid var(--color-border);
  border-radius: var(--radius-lg);
  padding: var(--space-lg);
  box-shadow: var(--shadow-sm);
}

/* Button base */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-sm) var(--space-lg);
  border: 2px solid transparent;
  border-radius: var(--radius-md);
  font-weight: 600;
  font-size: var(--text-base);
  cursor: pointer;
  transition: background var(--transition-fast), color var(--transition-fast), border-color var(--transition-fast);
  min-height: 44px;
  min-width: 44px;
  text-decoration: none;
  line-height: 1.2;
}

.btn:focus-visible {
  outline: 3px solid var(--color-primary-light);
  outline-offset: 2px;
}

.btn-primary {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn-primary:hover {
  background: var(--color-primary-light);
}

.btn-secondary {
  background: transparent;
  color: var(--color-primary);
  border-color: var(--color-primary);
}

.btn-secondary:hover {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}

.btn-sm {
  padding: var(--space-xs) var(--space-md);
  font-size: var(--text-sm);
  min-height: 36px;
}

.btn-icon {
  padding: var(--space-sm);
  background: transparent;
  border: 1px solid var(--color-border);
  border-radius: var(--radius-md);
  cursor: pointer;
  min-height: 44px;
  min-width: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  transition: background var(--transition-fast);
}

.btn-icon:hover {
  background: var(--color-bg-alt);
}

.btn-icon:focus-visible {
  outline: 3px solid var(--color-primary-light);
  outline-offset: 2px;
}

/* Form elements */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-xs);
}

.form-label {
  font-weight: 600;
  font-size: var(--text-sm);
  color: var(--color-text);
}

.form-input {
  padding: var(--space-sm) var(--space-md);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  font-family: var(--font-mono);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 44px;
  transition: border-color var(--transition-fast);
}

.form-input:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(30, 58, 95, 0.15);
}

.form-input:invalid:not(:placeholder-shown) {
  border-color: var(--color-error);
}

.form-hint {
  font-size: var(--text-sm);
  color: var(--color-text-muted);
}

.form-error {
  font-size: var(--text-sm);
  color: var(--color-error);
  display: none;
}

.form-input:invalid:not(:placeholder-shown) ~ .form-error {
  display: block;
}

.form-select {
  padding: var(--space-sm) var(--space-md);
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  font-size: var(--text-base);
  background: var(--color-bg);
  color: var(--color-text);
  min-height: 44px;
  cursor: pointer;
  transition: border-color var(--transition-fast);
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%236c757d' stroke-width='2' fill='none'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right var(--space-md) center;
  padding-right: var(--space-2xl);
}

.form-select:focus {
  outline: none;
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px rgba(30, 58, 95, 0.15);
}

/* Radio / toggle group */
.toggle-group {
  display: flex;
  border: 2px solid var(--color-border);
  border-radius: var(--radius-md);
  overflow: hidden;
}

.toggle-group input[type="radio"] {
  position: absolute;
  opacity: 0;
  width: 0;
  height: 0;
}

.toggle-group label {
  flex: 1;
  padding: var(--space-sm) var(--space-md);
  text-align: center;
  cursor: pointer;
  font-weight: 600;
  font-size: var(--text-sm);
  transition: background var(--transition-fast), color var(--transition-fast);
  min-height: 44px;
  display: flex;
  align-items: center;
  justify-content: center;
  border-right: 1px solid var(--color-border);
}

.toggle-group label:last-of-type {
  border-right: none;
}

.toggle-group input[type="radio"]:checked + label {
  background: var(--color-primary);
  color: var(--color-text-inverse);
}

.toggle-group input[type="radio"]:focus-visible + label {
  outline: 3px solid var(--color-primary-light);
  outline-offset: -3px;
}

/* Ad slot protection */
.ad-container {
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--color-bg-alt);
  border: 1px solid var(--color-border-light);
  border-radius: var(--radius-sm);
  overflow: hidden;
  margin-block: var(--space-lg);
}

.ad-container::before {
  content: "Advertisement";
  display: block;
  font-size: 0.7rem;
  color: var(--color-text-muted);
  text-align: center;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  position: absolute;
  top: 2px;
}

/* Reduced motion */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
    scroll-behavior: auto !important;
  }
}