:root {
  --bg: #0f172a;
  --panel: #111827;
  --panel-soft: #1f2937;
  --line: rgba(255,255,255,0.08);
  --text: #e5eefb;
  --muted: #9fb0c8;
  --accent: #60a5fa;
  --accent-2: #93c5fd;
  --success-bg: rgba(34, 197, 94, 0.16);
  --success-text: #86efac;
  --error-bg: rgba(239, 68, 68, 0.16);
  --error-text: #fca5a5;
  --shadow: 0 20px 50px rgba(0,0,0,0.35);
  --radius: 24px;
}

* { box-sizing: border-box; }
html, body { margin: 0; padding: 0; }
body {
  font-family: Arial, Helvetica, sans-serif;
  background:
    radial-gradient(circle at top, rgba(96,165,250,.18), transparent 28%),
    linear-gradient(180deg, #020617 0%, var(--bg) 100%);
  color: var(--text);
  min-height: 100vh;
}

.page {
  min-height: 100vh;
  display: grid;
  place-items: center;
  padding: 24px;
}

.card {
  width: min(760px, 100%);
  background: rgba(17, 24, 39, 0.94);
  border: 1px solid var(--line);
  border-radius: var(--radius);
  box-shadow: var(--shadow);
  padding: 28px;
}

.hero { margin-bottom: 24px; }
.hero h1 {
  margin: 10px 0 8px;
  font-size: clamp(1.8rem, 4vw, 2.6rem);
}
.hero p {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
}

.badge {
  display: inline-block;
  padding: 8px 12px;
  border-radius: 999px;
  background: rgba(96, 165, 250, 0.16);
  color: var(--accent-2);
  font-size: 0.82rem;
  letter-spacing: .04em;
}

.grid {
  display: grid;
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 16px;
}

.field {
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.field span {
  font-weight: bold;
}

.field input {
  width: 100%;
  border: 1px solid var(--line);
  border-radius: 16px;
  background: var(--panel-soft);
  color: var(--text);
  padding: 14px 16px;
  font-size: 1rem;
  outline: none;
  transition: border-color .2s ease, box-shadow .2s ease, transform .2s ease;
}

.field input:focus {
  border-color: rgba(147,197,253,.9);
  box-shadow: 0 0 0 4px rgba(96,165,250,.16);
  transform: translateY(-1px);
}

.actions {
  display: flex;
  gap: 12px;
  margin-top: 18px;
  flex-wrap: wrap;
}

.btn {
  border: 0;
  border-radius: 16px;
  padding: 13px 18px;
  font-size: 1rem;
  font-weight: bold;
  cursor: pointer;
  transition: transform .18s ease, opacity .18s ease;
}
.btn:hover { transform: translateY(-1px); }
.btn.primary {
  background: linear-gradient(135deg, var(--accent), var(--accent-2));
  color: #08111f;
}
.btn.secondary {
  background: #273449;
  color: var(--text);
}

.result-panel {
  margin-top: 26px;
  border-top: 1px solid var(--line);
  padding-top: 22px;
}
.result-panel h2,
.note h3 {
  margin-top: 0;
}

.notice {
  border-radius: 14px;
  padding: 12px 14px;
  margin-bottom: 14px;
}
.notice.success {
  background: var(--success-bg);
  color: var(--success-text);
}
.notice.error {
  background: var(--error-bg);
  color: var(--error-text);
}

.result-box {
  background: linear-gradient(180deg, rgba(96,165,250,.12), rgba(96,165,250,.05));
  border: 1px solid rgba(96,165,250,.22);
  border-radius: 20px;
  padding: 18px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.result-label {
  color: var(--muted);
  font-size: .92rem;
}

#resultValue {
  font-size: clamp(2rem, 8vw, 3.8rem);
  line-height: 1;
}

.extra { margin-top: 14px; }
.hint {
  color: var(--muted);
  margin: 0;
}
.comparison {
  margin: 0;
  font-weight: bold;
}
.comparison.ok { color: var(--success-text); }
.comparison.ko { color: #fda4af; }

.note {
  margin-top: 24px;
  border-top: 1px solid var(--line);
  padding-top: 20px;
}
.note p {
  color: var(--muted);
  margin-bottom: 0;
}
code {
  background: rgba(255,255,255,.06);
  border-radius: 8px;
  padding: 2px 6px;
}

@media (max-width: 640px) {
  .card { padding: 20px; }
  .grid { grid-template-columns: 1fr; }
  .actions { flex-direction: column; }
  .btn { width: 100%; }
}