* {
  box-sizing: border-box;
}

:root {
  --background-color: #f6f8fb;
  --surface-color: #ffffff;
  --surface-border: #e7ecf3;
  --input-bg: #ffffff;
  --primary-color: #2563eb;
  --primary-hover-color: #1d4ed8;
  --text-color: #1a1f29;
  --label-color: #5a6473;
  --border-color: #d6dce5;
  --error-color: #dc3545;
  --success-color: #198754;
  --border-radius: 12px;
  --box-shadow: 0 8px 24px -12px rgba(20, 30, 50, 0.18);
  --font-family: 'Inter', sans-serif;
  --mono-font: ui-monospace, 'SF Mono', 'Cascadia Code', 'Roboto Mono', Menlo, Consolas, monospace;
  color-scheme: light;
}

/* Dunkles Farbschema – Werte einmal als wiederverwendbarer Block. */
@media (prefers-color-scheme: dark) {
  /* Automatisch (System), solange nicht explizit "hell" gewählt wurde. */
  :root:not([data-theme="light"]) {
    --background-color: #0e1116;
    --surface-color: #171b22;
    --surface-border: #242b36;
    --input-bg: #11151b;
    --primary-color: #3b82f6;
    --primary-hover-color: #60a5fa;
    --text-color: #e6e8eb;
    --label-color: #9aa4b2;
    --border-color: #2a2f3a;
    --error-color: #ff7b72;
    --success-color: #3fb950;
    --box-shadow: 0 4px 14px rgba(0, 0, 0, 0.5);
    color-scheme: dark;
  }
}

/* Explizit per Umschalter gewählt. */
:root[data-theme="dark"] {
  --background-color: #0e1116;
  --surface-color: #171b22;
  --surface-border: #242b36;
  --input-bg: #11151b;
  --primary-color: #3b82f6;
  --primary-hover-color: #60a5fa;
  --text-color: #e6e8eb;
  --label-color: #9aa4b2;
  --border-color: #2a2f3a;
  --error-color: #ff7b72;
  --success-color: #3fb950;
  --box-shadow: 0 4px 14px rgba(0, 0, 0, 0.5);
  color-scheme: dark;
}

body {
  font-family: var(--font-family);
  background-color: var(--background-color);
  color: var(--text-color);
  margin: 0;
  padding: 2rem;
  display: flex;
  flex-direction: column;
  align-items: center;
  min-height: 100vh;
  transition: background-color 0.25s ease, color 0.25s ease;
}

.main-container {
  width: 100%;
  max-width: 900px;
  margin-bottom: 3rem;
}

.app-title {
  text-align: center;
  margin-bottom: 2.5rem;
}

/* Auf schmalen Screens stehen Sprach- und Theme-Schalter fest in den oberen Ecken und würden
   die zentrierte Überschrift überlagern. Daher den Seiteninhalt unter die Schalterleiste schieben.
   Auf breiten Screens (>=768px) ist seitlich genug Platz – dort bleibt es unverändert. */
@media (max-width: 768px) {
  body {
    padding-top: 5rem;
  }
}

h1 {
  margin: 0;
  font-weight: 600;
  font-size: clamp(1.6rem, 4vw, 2.1rem);
  letter-spacing: -0.02em;
}

.subtitle {
  margin: 0.5rem 0 0;
  color: var(--label-color);
  font-size: 0.95rem;
}

.converter-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

@media (min-width: 768px) {
  .converter-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.converter-panel {
  background-color: var(--surface-color);
  padding: 2rem;
  border: 1px solid var(--surface-border);
  border-radius: var(--border-radius);
  box-shadow: var(--box-shadow);
  display: flex;
  flex-direction: column;
  gap: 1.5rem;
  transition: background-color 0.25s ease, border-color 0.25s ease, box-shadow 0.25s ease;
}

.panel-eyebrow {
  margin: 0;
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--primary-color);
}

.input-group {
  display: flex;
  flex-direction: column;
}

.input-group label {
  margin-bottom: 0.5rem;
  color: var(--label-color);
  font-weight: 500;
}

.detected-format {
  font-weight: 400;
  font-size: 0.85rem;
  color: var(--primary-color);
  margin-left: 0.25rem;
}

input[type="number"],
input[type="text"],
select {
  width: 100%;
  padding: 0.75rem;
  border: 1px solid var(--border-color);
  border-radius: 4px;
  box-sizing: border-box;
  font-family: inherit;
  font-size: 1rem;
  background-color: var(--input-bg);
  color: var(--text-color);
  transition: background-color 0.25s ease, border-color 0.2s ease, color 0.25s ease;
}

/* Wertfelder technisch/monospace; Dropdowns behalten die Fließtextschrift. */
input[type="number"],
input[type="text"] {
  font-family: var(--mono-font);
}

select {
  cursor: pointer;
  text-overflow: ellipsis;
}

input:focus,
select:focus {
  outline: none;
  border-color: var(--primary-color);
  box-shadow: 0 0 0 3px rgba(0, 123, 255, 0.25);
}

input.invalid {
  border-color: var(--error-color);
}

input.invalid:focus {
  border-color: var(--error-color);
  box-shadow: 0 0 0 3px rgba(220, 53, 69, 0.25);
}

.timestamp-options {
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.timestamp-options input[type="checkbox"] {
  width: auto;
  accent-color: var(--primary-color);
}

.button-group {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 1rem;
}

button {
  cursor: pointer;
  background-color: var(--primary-color);
  color: white;
  border: 1px solid transparent;
  padding: 0.75rem;
  border-radius: 8px;
  font-size: 1rem;
  font-weight: 500;
  transition: background-color 0.2s ease, border-color 0.2s ease, transform 0.05s ease;
}

button:hover {
  background-color: var(--primary-hover-color);
}

button:active {
  transform: translateY(1px);
}

/* Sekundäre Aktion: zurückhaltend, um den Fokus auf "Kopieren" zu lenken. */
.btn-ghost {
  background-color: transparent;
  color: var(--primary-color);
  border-color: var(--border-color);
}

.btn-ghost:hover {
  background-color: var(--input-bg);
  border-color: var(--primary-color);
  color: var(--primary-color);
}

/* Menschenlesbare Ausgabe – schiebt sich ans untere Kartenende und füllt den Freiraum. */
.readout {
  display: none;
  margin-top: auto;
  padding-top: 1.5rem;
  border-top: 1px solid var(--surface-border);
}

.readout.is-visible {
  display: block;
}

.readout-relative {
  margin: 0 0 0.35rem;
  font-size: 1.4rem;
  font-weight: 600;
  letter-spacing: -0.01em;
  color: var(--text-color);
}

.readout-relative::first-letter {
  text-transform: uppercase;
}

.readout-absolute {
  margin: 0;
  color: var(--label-color);
  font-size: 0.95rem;
}

.date-time-container {
  display: flex;
  flex-direction: column;
  gap: 1rem;
}

.date-grid,
.time-grid {
  display: grid;
  gap: 1rem;
}

.date-grid {
  grid-template-columns: repeat(3, 1fr);
}

.time-grid {
  grid-template-columns: repeat(auto-fit, minmax(80px, 1fr));
}

.now-controls {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 1rem;
  align-items: center;
}

.calc-row {
  display: grid;
  grid-template-columns: minmax(64px, 0.8fr) 1.4fr auto auto;
  gap: 0.5rem;
  align-items: stretch;
}

.calc-btn {
  min-width: 3rem;
  font-size: 1.25rem;
  line-height: 1;
}

/* Live-Anzeige des aktuellen Timestamps – zentrierte Pille über dem Konverter. */
.live-now {
  display: flex;
  align-items: center;
  gap: 1rem;
  width: fit-content;
  max-width: 100%;
  margin: 0 auto 2rem;
  padding: 0.45rem 0.45rem 0.45rem 1.1rem;
  background-color: var(--surface-color);
  border: 1px solid var(--surface-border);
  border-radius: 999px;
  box-shadow: var(--box-shadow);
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.live-now-label {
  font-size: 0.72rem;
  font-weight: 600;
  letter-spacing: 0.09em;
  text-transform: uppercase;
  color: var(--primary-color);
}

.live-now-value {
  font-family: var(--mono-font);
  font-size: 1.15rem;
  font-weight: 600;
  color: var(--text-color);
  font-variant-numeric: tabular-nums;
}

.live-now .icon-btn {
  width: 2.4rem;
}

/* Eingabefeld mit angehängtem Aktions-Button (z. B. Kopieren). */
.field-with-action {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.5rem;
  align-items: stretch;
}

.readout-actions {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
  margin-top: 1rem;
}

.readout-actions button {
  font-size: 0.85rem;
  padding: 0.4rem 0.85rem;
}

.format-timezone-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.5rem;
}

.timezone-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.5rem;
  align-items: stretch;
}

.icon-btn {
  aspect-ratio: 1;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.icon-btn svg {
  width: 1.2rem;
  height: 1.2rem;
}

.info {
  max-width: 720px;
  margin: 3.5rem auto 0;
  line-height: 1.65;
  color: var(--label-color);
}

.info h2 {
  margin: 2.25rem 0 0.75rem;
  color: var(--text-color);
  font-size: 1.3rem;
  font-weight: 600;
  letter-spacing: -0.01em;
}

.info h2:first-child {
  margin-top: 0;
}

/* Einklappbarer Erläuterungstext: die erste Überschrift wird per JS zum Umschalter.
   Ohne JS bzw. ohne die Klasse .is-collapsed bleibt alles sichtbar (SEO). */
.info-toggle {
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.5rem;
  user-select: none;
}

.info-toggle::before {
  content: '';
  flex: none;
  width: 0.55rem;
  height: 0.55rem;
  border-right: 2px solid currentColor;
  border-bottom: 2px solid currentColor;
  transform: rotate(45deg); /* ausgeklappt: Chevron zeigt nach unten */
  transition: transform 0.2s ease;
}

.info.is-collapsed .info-toggle::before {
  transform: rotate(-45deg); /* eingeklappt: Chevron zeigt nach rechts */
}

.info-toggle:focus-visible {
  outline: 2px solid var(--primary-color);
  outline-offset: 3px;
  border-radius: 4px;
}

.info.is-collapsed .info-content {
  display: none;
}

.info h3 {
  margin: 1.5rem 0 0.5rem;
  color: var(--text-color);
  font-size: 1.05rem;
  font-weight: 600;
}

.info p {
  margin: 0 0 1rem;
}

.info ul,
.info ol {
  margin: 0 0 1rem;
  padding-left: 1.25rem;
}

.info li {
  margin-bottom: 0.4rem;
}

.info strong {
  color: var(--text-color);
  font-weight: 600;
}

.info code {
  font-family: var(--mono-font);
  font-size: 0.88em;
  background-color: var(--input-bg);
  border: 1px solid var(--surface-border);
  border-radius: 4px;
  padding: 0.1rem 0.35rem;
}

.site-footer {
  margin-top: auto;
  padding: 2rem 0;
  width: 100%;
  max-width: 900px;
  border-top: 1px solid var(--border-color);
  display: flex;
  justify-content: center;
}

.footer-content {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  color: var(--label-color);
  font-size: 0.9rem;
}

.footer-item {
  display: flex;
  gap: 0.5rem;
  align-items: center;
}

.footer-item a {
  color: var(--primary-color);
  text-decoration: none;
  font-weight: 500;
  transition: color 0.2s, text-decoration 0.2s;
}

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

@media (min-width: 576px) {
  .footer-content {
    flex-direction: row;
    gap: 2rem;
  }
}

.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(1rem);
  background-color: var(--text-color);
  color: #fff;
  padding: 0.75rem 1.25rem;
  border-radius: var(--border-radius);
  box-shadow: 0 6px 16px rgba(0, 0, 0, 0.2);
  font-size: 0.95rem;
  opacity: 0;
  pointer-events: none;
  transition: opacity 0.2s ease, transform 0.2s ease;
  z-index: 1000;
}

.toast.show {
  opacity: 1;
  transform: translateX(-50%) translateY(0);
}

.toast.success {
  background-color: var(--success-color);
}

.toast.error {
  background-color: var(--error-color);
}

/* Farbschema-Umschalter (System / Hell / Dunkel) */
.theme-switch {
  position: fixed;
  top: 1.25rem;
  right: 1.25rem;
  z-index: 100;
  display: inline-flex;
  gap: 0.125rem;
  padding: 0.25rem;
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 999px;
  box-shadow: var(--box-shadow);
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.theme-switch .theme-option {
  width: 2.1rem;
  height: 2.1rem;
  padding: 0;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  background: transparent;
  color: var(--label-color);
  border: none;
  border-radius: 999px;
  cursor: pointer;
  transition: background-color 0.2s ease, color 0.2s ease;
}

.theme-switch .theme-option:hover {
  background-color: var(--background-color);
  color: var(--text-color);
}

.theme-switch .theme-option.active {
  background-color: var(--primary-color);
  color: #ffffff;
}

.theme-switch .theme-option svg {
  width: 1.15rem;
  height: 1.15rem;
}

@media (max-width: 480px) {
  .theme-switch {
    top: 0.75rem;
    right: 0.75rem;
  }
}

/* Sprachumschalter – Gegenstück zum Theme-Switch, oben links. Echte Links pro Sprache. */
.lang-switch {
  position: fixed;
  top: 1.25rem;
  left: 1.25rem;
  z-index: 100;
  display: inline-flex;
  gap: 0.125rem;
  padding: 0.25rem;
  background-color: var(--surface-color);
  border: 1px solid var(--border-color);
  border-radius: 999px;
  box-shadow: var(--box-shadow);
  transition: background-color 0.25s ease, border-color 0.25s ease;
}

.lang-switch a {
  display: inline-flex;
  align-items: center;
  padding: 0.3rem 0.7rem;
  border-radius: 999px;
  font-size: 0.85rem;
  font-weight: 600;
  text-decoration: none;
  color: var(--label-color);
  transition: background-color 0.2s ease, color 0.2s ease;
}

.lang-switch a:hover {
  background-color: var(--background-color);
  color: var(--text-color);
}

.lang-switch a.active {
  background-color: var(--primary-color);
  color: #ffffff;
}

@media (max-width: 480px) {
  .lang-switch {
    top: 0.75rem;
    left: 0.75rem;
  }
}