:root {
  color-scheme: light dark;
  font-family: system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
  line-height: 1.4;
}

body {
  margin: 0;
  min-height: 100vh;
  background: linear-gradient(160deg, #1f2937 0%, #111827 50%, #0f172a 100%);
  color: #f9fafb;
  display: flex;
  justify-content: center;
  align-items: stretch;
}

.container {
  width: min(720px, 92vw);
  margin: 3rem auto;
  padding: 2rem 2.4rem;
  background: rgba(15, 23, 42, 0.8);
  border-radius: 18px;
  border: 1px solid rgba(148, 163, 184, 0.2);
  box-shadow: 0 32px 60px rgba(15, 23, 42, 0.25);
}

h1 {
  margin-top: 0;
  font-size: clamp(1.8rem, 2.5vw, 2.4rem);
}

header p {
  margin-bottom: 2rem;
  color: #cbd5f5;
}

form {
  display: grid;
  gap: 1.4rem;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 0.5rem;
}

label {
  font-weight: 600;
}

input {
  padding: 0.75rem 1rem;
  border-radius: 10px;
  border: 1px solid rgba(148, 163, 184, 0.35);
  background: rgba(15, 23, 42, 0.7);
  color: inherit;
  transition: border-color 0.2s ease;
}

input:focus {
  border-color: #38bdf8;
  outline: none;
}

small {
  color: #9ca3af;
}

button {
  padding: 0.9rem 1.2rem;
  border-radius: 12px;
  border: none;
  background: linear-gradient(135deg, #0ea5e9, #22d3ee);
  color: #0f172a;
  font-weight: 700;
  font-size: 1rem;
  cursor: pointer;
  transition: transform 0.2s ease, box-shadow 0.2s ease;
}

button:hover {
  transform: translateY(-1px);
  box-shadow: 0 10px 24px rgba(14, 165, 233, 0.35);
}

#result,
#error {
  margin-top: 2rem;
  padding: 1.25rem;
  border-radius: 12px;
  background: rgba(30, 64, 175, 0.3);
  border: 1px solid rgba(96, 165, 250, 0.5);
}

#error {
  background: rgba(220, 38, 38, 0.21);
  border-color: rgba(248, 113, 113, 0.6);
  color: #fecaca;
}

.hidden {
  display: none;
}