/* --- Variables & Theme --- */
:root {
  color-scheme: light dark;
  --background-color: white;
  --text-color: black;
  --muted-color: #666;
  --border-color: #ccc;
  --soft-background: rgba(127, 127, 127, 0.1);
  --focus-color: #075ec8;
  --success-color: #187a2f;
  --error-color: #b00020;
}

@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --background-color: #1e1e1e;
    --text-color: #f0f0f0;
    --muted-color: #999;
    --border-color: #555;
    --soft-background: rgba(255, 255, 255, 0.08);
    --focus-color: #83b9ff;
    --success-color: #6fcf82;
    --error-color: #ff8a9a;
  }
}

[data-theme="light"] {
  color-scheme: light;
  --background-color: white;
  --text-color: black;
  --muted-color: #666;
  --border-color: #ccc;
  --soft-background: rgba(127, 127, 127, 0.1);
  --focus-color: #075ec8;
  --success-color: #187a2f;
  --error-color: #b00020;
}

[data-theme="dark"] {
  color-scheme: dark;
  --background-color: #1e1e1e;
  --text-color: #f0f0f0;
  --muted-color: #999;
  --border-color: #555;
  --soft-background: rgba(255, 255, 255, 0.08);
  --focus-color: #83b9ff;
  --success-color: #6fcf82;
  --error-color: #ff8a9a;
}

/* --- Base --- */
*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI",
    Roboto, "Helvetica Neue", Arial, sans-serif;
  background-color: var(--background-color);
  color: var(--text-color);
  width: 100%;
  max-width: 640px;
  margin: 20px auto;
  padding: 0 20px;
  line-height: 1.5;
}

/* --- Skip Link --- */
.skip-link {
  position: absolute;
  top: -40px;
  left: 0;
  background: var(--text-color);
  color: var(--background-color);
  padding: 6px 12px;
  text-decoration: none;
  font-size: 14px;
}

.skip-link:focus {
  top: 0;
}

/* --- Header --- */
header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 32px;
}

h1 {
  font-size: 1rem;
  font-weight: bold;
  margin: 0;
}

h1 a {
  color: inherit;
  text-decoration: none;
}

.theme-toggle {
  min-height: 32px;
  margin: 0;
  padding: 4px 7px;
  border: 0;
  border-radius: 6px;
  color: var(--muted-color);
  background: transparent;
  font: inherit;
  font-size: 0.875rem;
  cursor: pointer;
}

.theme-toggle:hover {
  color: var(--text-color);
  background: var(--soft-background);
}

.theme-toggle:focus-visible {
  outline: 3px solid color-mix(in srgb, var(--focus-color) 60%, transparent);
  outline-offset: 2px;
}

/* --- Main content --- */
main {
  margin-bottom: 20px;
}

label {
  display: block;
  margin-bottom: 8px;
}

textarea {
  display: block;
  width: 100%;
  resize: none;
  overflow: hidden;
  font-family: inherit;
  font-size: 16px;
  line-height: 1.5;
  background-color: var(--background-color);
  color: var(--text-color);
  border: 1px solid var(--border-color);
  padding: 8px;
  min-height: 3rem;
  margin-bottom: 20px;
}

textarea:focus {
  outline: 2px solid var(--text-color);
  outline-offset: 1px;
}

select {
  max-width: 100%;
  padding: 6px;
  font: inherit;
  font-size: 16px;
}

.carrier-choice {
  margin-bottom: 20px;
}

.choice-help {
  margin: 8px 0 0;
  color: var(--muted-color);
  font-size: 14px;
}

/* --- Output area --- */
.output-wrapper {
  margin-bottom: 20px;
}

.output-label {
  display: block;
  font-size: 0.875rem;
  color: var(--muted-color);
  margin-bottom: 6px;
}

#output {
  display: block;
  font-family: ui-monospace, "SF Mono", Menlo, Consolas, monospace;
  font-size: 0.875rem;
  word-break: break-all;
  white-space: pre-wrap;
  line-height: 1.6;
  min-height: 1.5em;
  padding: 10px 12px;
  border: 1px solid var(--border-color);
  border-radius: 8px;
  cursor: pointer;
}

#output.placeholder {
  color: var(--muted-color);
  font-family: inherit;
  font-size: 1rem;
  cursor: default;
}

#output[aria-disabled="true"] {
  pointer-events: none;
}

#output:focus {
  outline: 2px solid var(--text-color);
  outline-offset: 2px;
}

.copy-hint {
  display: block;
  margin-top: 8px;
  font-size: 0.875rem;
  color: var(--muted-color);
}

/* --- Actions row --- */
.actions {
  margin-bottom: 20px;
}

.copy-feedback {
  font-size: 14px;
  color: var(--success-color);
  opacity: 0;
  transition: opacity 0.2s ease;
}

.copy-feedback[data-state="error"] {
  color: var(--error-color);
}

.copy-feedback[data-state="success"] {
  color: var(--success-color);
}

.copy-feedback.visible {
  opacity: 1;
}

/* --- Carrier badge --- */
.carrier-badge {
  display: inline-block;
  font-size: 12px;
  color: var(--muted-color);
  margin-bottom: 4px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

/* --- Footer --- */
.related-tools {
  margin-top: 32px;
  padding-top: 20px;
  border-top: 1px solid var(--border-color);
  color: var(--muted-color);
  font-size: 14px;
}

.related-tools h2 {
  margin: 0 0 8px;
  font-size: 14px;
}

.related-tools p {
  margin: 0;
}

.related-tools a {
  color: inherit;
  text-decoration-color: currentColor;
  text-underline-offset: 2px;
}

footer {
  margin-top: 40px;
  font-size: 14px;
  color: var(--muted-color);
}

/* --- Mobile --- */
@media (max-width: 768px) {
  body {
    margin: 20px 0;
  }

  input,
  textarea,
  select {
    font-size: 16px;
  }
}

@media (max-width: 480px) {
  header {
    align-items: flex-start;
    gap: 12px;
  }
}

@media (prefers-reduced-motion: reduce) {
  .copy-feedback {
    transition: none;
  }
}