:root {
  --bg: #0c1624;
  --card: #132238;
  --text: #eef6ff;
  --muted: #94a8c4;
  --green: #34d399;
  --blue: #60a5fa;
}

* { box-sizing: border-box; }

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Work Sans", sans-serif;
  background: linear-gradient(135deg, #0c1624 0%, #0a2820 100%);
  color: var(--text);
}

header {
  padding: 2rem 1.5rem 1rem;
  text-align: center;
}

h1 {
  font-family: "Literata", serif;
  margin: 0;
  font-size: 2.5rem;
  background: linear-gradient(120deg, var(--blue), var(--green));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  animation: shimmer 6s ease-in-out infinite;
}

@keyframes shimmer {
  0%, 100% { filter: hue-rotate(0deg); }
  50% { filter: hue-rotate(15deg); }
}

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

.tabs {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.5rem;
  padding: 0 1rem;
}

.tabs button {
  font-family: inherit;
  border: 1px solid #2a4060;
  background: var(--card);
  color: var(--text);
  padding: 0.45rem 0.9rem;
  border-radius: 999px;
  cursor: pointer;
  transition: transform 0.15s, background 0.15s;
}

.tabs button.active {
  background: linear-gradient(135deg, #2563eb, #059669);
  border-color: transparent;
}

.tabs button:hover { transform: translateY(-2px); }

.converter {
  max-width: 520px;
  margin: 1.5rem auto 3rem;
  padding: 1.5rem;
  background: rgba(19, 34, 56, 0.9);
  border: 1px solid #2a4060;
  border-radius: 20px;
  animation: rise 0.45s ease-out;
}

@keyframes rise {
  from { opacity: 0; transform: translateY(12px); }
  to { opacity: 1; transform: none; }
}

.field { margin-bottom: 1rem; }
.field label { display: block; font-size: 0.85rem; color: var(--muted); margin-bottom: 0.35rem; }

.field-row {
  display: grid;
  grid-template-columns: 1fr auto;
  gap: 0.5rem;
}

input, select {
  font-family: inherit;
  font-size: 1rem;
  padding: 0.55rem 0.65rem;
  border-radius: 10px;
  border: 1px solid #2a4060;
  background: #0c1624;
  color: var(--text);
  width: 100%;
}

.result {
  margin-top: 1.25rem;
  padding: 1rem;
  border-radius: 12px;
  background: rgba(52, 211, 153, 0.1);
  border: 1px solid rgba(52, 211, 153, 0.35);
  font-family: "Literata", serif;
  font-size: 1.35rem;
}

.fx-note { font-size: 0.8rem; color: var(--muted); margin-top: 0.75rem; }

footer {
  text-align: center;
  padding: 1.5rem;
  color: var(--muted);
  font-size: 0.9rem;
}