/* Minimal, clean UI with smooth transitions (HSL colors) */
:root {
  --bg: hsl(219 47% 8%);
  --panel: hsl(219 44% 12%);
  --accent: hsl(205 100% 62%);
  --accent-2: hsl(191 100% 50%);
  --text: hsl(211 59% 93%);
  --muted: hsl(211 26% 69%);
  --ok: hsl(140 86% 71%);
  --shadow: 0 10px 30px hsl(0 0% 0% / 0.35);
}
* { box-sizing: border-box; }
html, body { height: 100%; }
body {
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Arial, Noto Sans, "Apple Color Emoji", "Segoe UI Emoji";
  background: radial-gradient(1200px 600px at 80% -10%, hsl(205 100% 62% / .15), transparent 60%),
              radial-gradient(900px 500px at -10% 20%, hsl(191 100% 50% / .12), transparent 60%),
              var(--bg);
  color: var(--text);
  display: grid;
  place-items: center;
  padding: 24px;
}
.card {
  width: min(680px, 92vw);
  background: linear-gradient(180deg, hsl(0 0% 100% / .02), hsl(0 0% 100% / .01)), var(--panel);
  border: 1px solid hsl(0 0% 100% / .08);
  border-radius: 24px;
  box-shadow: var(--shadow);
  padding: 20px;
}
.header { display: flex; align-items: center; gap: 12px; margin-bottom: 12px; }
.logo { width: 28px; height: 28px; }
.title { font-size: 1.25rem; font-weight: 700; letter-spacing: .2px; }
.subtitle { color: var(--muted); font-size: .9rem; margin-bottom: 10px; }
.row { margin-bottom: 10px; }
.input {
  background: hsl(0 0% 100% / .04);
  border: 1px solid hsl(0 0% 100% / .10);
  border-radius: 14px;
  padding: 12px 14px;
  color: var(--text);
  font-size: 1rem;
  outline: none;
  width: 100%;
  transition: border .2s ease, background .2s ease, transform .05s ease;
}
.input:focus { border-color: var(--accent); transform: translateY(-1px); }
.label { display: block; font-size: .9rem; margin-bottom: 6px; color: var(--muted); }
.result { display: flex; align-items: center; gap: 10px; margin-top: 8px; }
.result-output {
  font-size: 1.75rem; font-weight: 800; letter-spacing: .4px;
  background: linear-gradient(90deg, var(--accent), var(--accent-2));
  -webkit-background-clip: text; background-clip: text; color: transparent;
}
.btn {
  cursor: pointer; border: 1px solid hsl(0 0% 100% / .12);
  background: hsl(0 0% 100% / .06); color: var(--text);
  padding: 10px 14px; border-radius: 12px; font-weight: 600;
  transition: transform .05s ease, background .2s ease, border .2s ease, opacity .2s ease;
}
.btn:hover { background: hsl(0 0% 100% / .12); }
.btn:active { transform: translateY(1px); }
.copy-ok { color: var(--ok); font-weight: 700; opacity: .9; }
.footer { margin-top: 12px; display: flex; justify-content: space-between; gap: 8px; color: var(--muted); font-size: .8rem; }
.history { margin-top: 14px; border-top: 1px dashed hsl(0 0% 100% / .12); padding-top: 10px; opacity: .85; }
.hist-title { font-size: .95rem; color: var(--muted); margin-bottom: 8px; }
.hist-list { list-style: none; margin: 0; padding: 0; display: grid; gap: 6px; max-height: 220px; overflow: auto; }
.hist-item {
  display: flex; justify-content: space-between; gap: 8px;
  background: hsl(0 0% 100% / .04);
  border: 1px dashed hsl(0 0% 100% / .12);
  padding: 10px 12px; border-radius: 12px; font-size: .95rem;
}
.small { font-size: .8rem; color: var(--muted); }
.note { opacity: .75; }
.hist-time { font-size: .75rem; color: var(--muted); margin-left: auto; }
.hist-right { display: flex; align-items: baseline; gap: 10px; }
@media (max-width: 560px) { .grid { grid-template-columns: 1fr; } }