:root {
  --bg-main: #070b15;
  --bg-secondary: #0e1830;
  --card-bg: rgba(15, 26, 47, 0.88);
  --card-border: rgba(143, 178, 241, 0.24);
  --text-main: #e9f2ff;
  --text-muted: #a8bcdf;
  --primary: #3ad1c9;
  --primary-strong: #2f8ff0;
  --danger: #ff7f8f;
  --shadow: 0 24px 52px rgba(3, 8, 20, 0.56);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: "Outfit", sans-serif;
  color: var(--text-main);
  background:
    radial-gradient(circle at 10% 8%, rgba(58, 209, 201, 0.18), transparent 34%),
    radial-gradient(circle at 92% 10%, rgba(47, 143, 240, 0.18), transparent 32%),
    linear-gradient(150deg, #040812, #0a1428 40%, #0b162c);
  padding: 24px;
}

.app-shell {
  width: min(920px, 100%);
  margin: 0 auto;
  display: grid;
  gap: 14px;
}

.app-header {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 16px;
  box-shadow: var(--shadow);
}

.eyebrow {
  margin: 0;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-size: 0.76rem;
}

h1 {
  margin: 5px 0 0;
  font-size: clamp(1.4rem, 3.6vw, 2rem);
}

.converter-card {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  padding: 16px;
  box-shadow: var(--shadow);
  display: grid;
  gap: 12px;
}

.category-row {
  display: grid;
  gap: 6px;
  color: var(--text-muted);
}

label,
.input-label {
  font-size: 0.9rem;
  color: var(--text-muted);
  margin: 0;
}

select,
input,
.swap-btn {
  border-radius: 12px;
  border: 1px solid rgba(143, 178, 241, 0.38);
  font-family: inherit;
  transition: border-color 0.18s ease, transform 0.18s ease, filter 0.18s ease;
}

select,
input {
  width: 100%;
  background: rgba(6, 12, 24, 0.96);
  color: var(--text-main);
  padding: 11px 12px;
  font-size: 0.95rem;
}

input:focus,
select:focus {
  outline: 2px solid rgba(58, 209, 201, 0.4);
  border-color: rgba(58, 209, 201, 0.66);
}

.converter-grid {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: 10px;
  align-items: end;
}

.input-card {
  border: 1px solid rgba(143, 178, 241, 0.2);
  border-radius: 14px;
  background: rgba(8, 15, 30, 0.75);
  padding: 12px;
  display: grid;
  gap: 8px;
}

.swap-btn {
  height: 44px;
  padding: 0 12px;
  border: 0;
  cursor: pointer;
  font-weight: 700;
  color: #041621;
  background: linear-gradient(140deg, var(--primary), var(--primary-strong));
}

.swap-btn:hover {
  transform: translateY(-1px);
  filter: brightness(1.04);
}

.status,
.error {
  min-height: 20px;
  margin: 0;
  font-size: 0.9rem;
}

.status {
  color: var(--text-muted);
}

.error {
  color: var(--danger);
}

@media (max-width: 760px) {
  .converter-grid {
    grid-template-columns: 1fr;
    align-items: stretch;
  }

  .swap-btn {
    width: 100%;
  }
}

@media (max-width: 520px) {
  body {
    padding: 14px;
  }

  .app-header,
  .converter-card {
    padding: 14px;
  }
}