RegisterFrontend/public/css/fallback/register.css

/* Basic button fallbacks (older browsers / when Tailwind v4 utilities fail) */
.fallback-btn {
  display: inline-block;
  padding: 0.75rem 1.5rem;
  font-size: 1.125rem;
  line-height: 1.2;
  font-weight: 500;
  border-radius: 0.5rem;
  border: none;
  cursor: pointer;
  text-align: center;
  text-decoration: none;
  background: #555;
  color: #fff;
  box-sizing: border-box;
}

.fallback-btn--primary {
  background: #1d4ed8; /* blue-700 */
}

.fallback-btn--primary:hover,
.fallback-btn--primary:focus {
  background: #1e40af; /* blue-800 */
}

.fallback-btn--secondary {
  background: #1f2937; /* gray-800 */
}

.fallback-btn--secondary:hover,
.fallback-btn--secondary:focus {
  background: #111827; /* gray-900 */
}

.fallback-btn:disabled,
.fallback-btn[aria-disabled="true"] {
  opacity: 0.7;
  cursor: not-allowed;
}

.fallback-btn--auto {
  width: 100%;
}

@media (min-width: 640px) {
  .fallback-btn--auto {
    width: auto;
  }
}

/* Spinner alignment fallback */
.fallback-btn svg {
  vertical-align: middle;
}

/* --- Enhanced slider (mode toggle) fallbacks --- */
.register-mode-toggle {
  display: flex;
  border: 1px solid #1d4ed8;
  border-radius: 0.75rem;
  overflow: hidden;
  background: #f9fafb;
  position: relative;
  max-width: 320px;
  margin: 0 auto 1.25rem auto;
}

.register-mode-toggle button {
  flex: 1 1 0;
  background: #e5e7eb !important; /* slate-200 */
  color: #1e3a8a !important;      /* blue-800 */
  padding: 0.75rem 1rem;
  font-weight: 700;
  font-size: 1.05rem;
  font-family: inherit;
  border: none;
  outline: none;
  box-shadow: none;
  cursor: pointer;
  position: relative;
  opacity: 1 !important;
  border-right: 1px solid #1d4ed8;
  /* --- Smooth transition for background, color, box-shadow, border --- */
  transition: 
    background 0.35s cubic-bezier(.4,0,.2,1),
    color 0.35s cubic-bezier(.4,0,.2,1),
    box-shadow 0.35s cubic-bezier(.4,0,.2,1),
    border 0.35s cubic-bezier(.4,0,.2,1);
}

.register-mode-toggle button:last-child {
  border-right: none;
}

.register-mode-toggle button.active,
.register-mode-toggle button[aria-selected="true"] {
  background: #1d4ed8 !important; /* blue-700 */
  color: #fff !important;
  /* Add a subtle shadow for depth */
  box-shadow: 0 2px 12px 0 rgba(30,64,175,0.08);
}

.register-mode-toggle button.active::after,
.register-mode-toggle button[aria-selected="true"]::after {
  content: "";
  position: absolute;
  inset: 0;
  border: 2px solid #1d4ed8;
  border-radius: 0; /* <-- changed from 0.75rem to 0 */
  pointer-events: none;
  /* Animate border appearance */
  transition: border 0.35s cubic-bezier(.4,0,.2,1);
}

/* Provide a minimal focus style for accessibility */
.register-mode-toggle button:focus-visible {
  box-shadow: 0 0 0 3px #bfdbfe !important;
}

@media (hover:hover) {
  .register-mode-toggle button:hover:not(.active) {
    background: #cbd5e1 !important; /* slate-300 */
    color: #1e3a8a !important;
    /* Slight shadow on hover for feedback */
    box-shadow: 0 1px 6px 0 rgba(30,64,175,0.06);
  }
}

/* Graceful degradation for very old browsers */
@supports not (gap: 1rem) {
  .register-mode-toggle button {
    margin-right: 1px;
  }
  .register-mode-toggle button:last-child {
    margin-right: 0;
  }
}

/* High contrast / prefers-reduced-transparency environments */
@media (prefers-contrast: more) {
  .register-mode-toggle button.active {
    background: #003caa !important;
  }
}

/* When no blur support we already ensure readable background elsewhere */

/* --- Safari-specific fallback for buttons and toggle --- */
@media not all and (min-resolution:.001dpcm) {
  @supports (-webkit-touch-callout: none) {
    .fallback-btn,
    .register-mode-toggle button {
      /* Safari sometimes ignores border-radius on buttons */
      border-radius: 8px !important;
      -webkit-border-radius: 8px !important;
      /* Safari ignores some box-shadow, so add fallback */
      box-shadow: 0 2px 8px 0 rgba(30,64,175,0.08);
      -webkit-box-shadow: 0 2px 8px 0 rgba(30,64,175,0.08);
    }
    .register-mode-toggle {
      /* Safari fallback for flex gap */
      gap: 0 !important;
    }
  }
}

/* --- Legacy browser fallback for border-radius and appearance --- */
.fallback-btn,
.register-mode-toggle button {
  border-radius: 0.5rem;
  /* Fallback for very old browsers */
  -webkit-border-radius: 0.5rem;
  -moz-border-radius: 0.5rem;
  /* Remove default button appearance */
  appearance: none;
  -webkit-appearance: none;
  -moz-appearance: none;
}