:root {
  --text: #1c2333;
  --muted: #5f6b7a;
  --border: #dde3ea;
  --page: #f3f5f9;
  --surface: #ffffff;
  --surface-sunken: #f8f9fc;
  --accent: #4f46e5;
  --accent-hover: #4338ca;
  --accent-soft: #eef0ff;
  --hero-start: #4f46e5;
  --hero-end: #0ea5e9;
  --focus-ring: rgb(79 70 229 / 30%);
  --error-text: #9f1239;
  --error-background: #fff1f2;
  --error-border: #fecdd3;
  --shadow: 0 1px 2px rgb(16 24 40 / 6%), 0 12px 32px rgb(16 24 40 / 8%);
  --radius: 14px;
}

@media (prefers-color-scheme: dark) {
  :root {
    --text: #e6e9ef;
    --muted: #9aa4b2;
    --border: #2c3442;
    --page: #0f131a;
    --surface: #171c25;
    --surface-sunken: #12161e;
    --accent: #818cf8;
    --accent-hover: #a5b4fc;
    --accent-soft: #232a45;
    --hero-start: #3730a3;
    --hero-end: #0369a1;
    --focus-ring: rgb(129 140 248 / 35%);
    --error-text: #fda4af;
    --error-background: #2a1218;
    --error-border: #5b1f2c;
    --shadow: 0 1px 2px rgb(0 0 0 / 30%), 0 12px 32px rgb(0 0 0 / 35%);
  }
}

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

body {
  margin: 0;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, sans-serif;
  line-height: 1.5;
  color: var(--text);
  background: var(--page);
}

.visually-hidden {
  position: absolute;
  width: 1px;
  height: 1px;
  overflow: hidden;
  clip-path: inset(50%);
  white-space: nowrap;
}

/* Header */

.hero {
  padding: 2.5rem 1rem 5rem;
  color: #ffffff;
  background: linear-gradient(135deg, var(--hero-start), var(--hero-end));
}

.hero-inner {
  max-width: 56rem;
  margin: 0 auto;
  display: flex;
  align-items: center;
  gap: 1rem;
}

.logo {
  display: grid;
  place-items: center;
  width: 3.25rem;
  height: 3.25rem;
  flex-shrink: 0;
  font-weight: 700;
  font-size: 1.1rem;
  background: rgb(255 255 255 / 18%);
  border: 1px solid rgb(255 255 255 / 30%);
  border-radius: 12px;
}

h1 {
  margin: 0;
  font-size: 1.9rem;
  letter-spacing: -0.02em;
}

.tagline {
  margin: 0.15rem 0 0;
  opacity: 0.85;
}

/* Card */

main {
  flex: 1;
  width: 100%;
  max-width: 56rem;
  margin: -3.5rem auto 0;
  padding: 0 1rem 2rem;
}

.card {
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  overflow: hidden;
}

.toolbar {
  display: flex;
  align-items: center;
  gap: 0.75rem;
  padding: 0.9rem 1.25rem;
  border-bottom: 1px solid var(--border);
}

.language-chip {
  padding: 0.4rem 0.9rem;
  font-weight: 600;
  color: var(--accent);
  background: var(--accent-soft);
  border-radius: 999px;
}

.arrow {
  color: var(--muted);
}

select {
  font: inherit;
  font-weight: 600;
  color: var(--text);
  background: var(--surface);
  border: 1px solid var(--border);
  border-radius: 999px;
  padding: 0.4rem 0.9rem;
  cursor: pointer;
}

select:disabled {
  color: var(--muted);
  cursor: wait;
}

/* Panels: side by side on wide screens, stacked on phones */

.panels {
  display: grid;
  grid-template-columns: 1fr 1fr;
}

.panel {
  display: flex;
  flex-direction: column;
  padding: 1rem 1.25rem;
}

.panel-output {
  background: var(--surface-sunken);
  border-left: 1px solid var(--border);
}

.panel-label {
  margin-bottom: 0.4rem;
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.04em;
  text-transform: uppercase;
  color: var(--muted);
}

textarea {
  flex: 1;
  width: 100%;
  min-height: 10rem;
  padding: 0;
  font: inherit;
  font-size: 1.15rem;
  color: var(--text);
  background: transparent;
  border: none;
  resize: vertical;
}

textarea:focus {
  outline: none;
}

textarea::placeholder {
  color: var(--muted);
  opacity: 0.7;
}

.panel:focus-within .panel-label {
  color: var(--accent);
}

@media (max-width: 640px) {
  .panels {
    grid-template-columns: 1fr;
  }

  .panel-output {
    border-left: none;
    border-top: 1px solid var(--border);
  }
}

/* Actions */

.actions {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.9rem 1.25rem;
  border-top: 1px solid var(--border);
}

.elapsed-time {
  margin: 0;
  font-size: 0.9rem;
  color: var(--muted);
}

button {
  display: inline-flex;
  align-items: center;
  gap: 0.5rem;
  margin-left: auto;
  padding: 0.6rem 1.5rem;
  font: inherit;
  font-weight: 600;
  color: #ffffff;
  background: var(--accent);
  border: none;
  border-radius: 999px;
  cursor: pointer;
  transition:
    background 0.15s,
    transform 0.15s;
}

button:hover:not(:disabled) {
  background: var(--accent-hover);
}

button:active:not(:disabled) {
  transform: translateY(1px);
}

button:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

button:focus-visible,
select:focus-visible {
  outline: none;
  box-shadow: 0 0 0 4px var(--focus-ring);
}

/* The spinner shows while a translation request is in flight. */
.spinner {
  display: none;
  width: 1em;
  height: 1em;
  border: 2px solid rgb(255 255 255 / 40%);
  border-top-color: #ffffff;
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

form[aria-busy="true"] .spinner {
  display: inline-block;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

/* Errors */

.error {
  margin: 1rem 0 0;
  padding: 0.85rem 1rem;
  color: var(--error-text);
  background: var(--error-background);
  border: 1px solid var(--error-border);
  border-radius: 10px;
}

/* Footer */

footer {
  padding: 1.5rem 1rem;
  text-align: center;
  font-size: 0.85rem;
  color: var(--muted);
}

footer a {
  color: var(--accent);
}