/* Minimal, modern, readable default styles */

:root {
  --bg-0: #fef5ff;
  --bg-1: #fff9e6;
  --panel: rgba(255, 255, 255, 0.85);
  --panel-border: rgba(255, 182, 193, 0.4);
  --text: #2d3748;
  --muted: #718096;
  --accent-a: #ff6b9d;
  --accent-b: #ffa07a;
  --shadow: 0 20px 60px rgba(255, 105, 180, 0.25);

  --key: rgba(173, 216, 230, 0.35);
  --key-border: rgba(100, 149, 237, 0.3);
  --key-hover: rgba(135, 206, 250, 0.5);
  --key-active: rgba(100, 149, 237, 0.6);
  --focus: rgba(255, 182, 193, 0.8);

  --op: rgba(255, 182, 193, 0.5);
  --op-border: rgba(255, 105, 180, 0.6);
  --eq: rgba(144, 238, 144, 0.5);
  --eq-border: rgba(60, 179, 113, 0.7);
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  color: var(--text);
  font: 16px/1.5 ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto,
    Helvetica, Arial, "Apple Color Emoji", "Segoe UI Emoji";
  background:
    radial-gradient(1200px 900px at 10% 0%, rgba(255, 182, 193, 0.35), transparent 60%),
    radial-gradient(900px 700px at 90% 20%, rgba(173, 216, 230, 0.40), transparent 55%),
    radial-gradient(800px 600px at 50% 80%, rgba(255, 255, 153, 0.25), transparent 50%),
    linear-gradient(180deg, var(--bg-0), var(--bg-1));
}

.page {
  min-height: 100%;
  display: grid;
  place-items: center;
  padding: 28px;
}

.calc {
  width: min(440px, 100%);
  padding: 22px;
  border-radius: 20px;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  box-shadow: var(--shadow);
  backdrop-filter: blur(10px);
}

.badge {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 6px 10px;
  border-radius: 999px;
  font-size: 12px;
  letter-spacing: 0.12em;
  font-weight: 700;
  color: #4a1942;
  background: linear-gradient(90deg, rgba(255, 105, 180, 0.85), rgba(255, 182, 193, 0.85));
  border: 1px solid rgba(255, 105, 180, 0.4);
}

.calc__header {
  display: grid;
  gap: 6px;
}

.calc__title {
  margin: 10px 0 0;
  font-size: 28px;
  line-height: 1.1;
  letter-spacing: -0.02em;
}

.accent {
  background: linear-gradient(90deg, var(--accent-a), var(--accent-b));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.subtitle {
  margin: 0 0 18px;
  font-size: 18px;
  color: var(--muted);
}

.calc__screen {
  margin-top: 8px;
  padding: 14px 14px 12px;
  border-radius: 16px;
  background: rgba(255, 255, 255, 0.7);
  border: 1px solid rgba(173, 216, 230, 0.5);
}

.calc__expression {
  min-height: 18px;
  font-size: 13px;
  letter-spacing: 0.02em;
  color: #718096;
  text-align: right;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.calc__display {
  margin-top: 4px;
  font-size: 44px;
  line-height: 1.05;
  text-align: right;
  letter-spacing: -0.02em;
  font-variant-numeric: tabular-nums;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.calc__keys {
  margin-top: 14px;
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 10px;
}

.key {
  appearance: none;
  user-select: none;
  -webkit-tap-highlight-color: transparent;
  display: grid;
  place-items: center;
  height: 56px;
  padding: 0 10px;
  border-radius: 14px;
  background: var(--key);
  border: 1px solid var(--key-border);
  color: #2d3748;
  font-size: 18px;
  font-weight: 650;
  letter-spacing: 0.01em;
  text-decoration: none;
  cursor: pointer;
  transition: transform 90ms ease, background 120ms ease, border-color 120ms ease;
}

.key:hover {
  background: var(--key-hover);
}

.key:active {
  background: var(--key-active);
  transform: translateY(1px);
}

.key:focus-visible {
  outline: 2px solid var(--focus);
  outline-offset: 2px;
}

.key--wide {
  grid-column: span 2;
}

.key--util {
  background: rgba(255, 218, 185, 0.4);
}

.key--op {
  background: var(--op);
  border-color: var(--op-border);
}

.key--equal {
  background: var(--eq);
  border-color: var(--eq-border);
}

.calc__meta {
  margin-top: 12px;
  text-align: center;
  color: #718096;
  font-size: 13px;
}

@media (prefers-reduced-motion: no-preference) {
  .calc {
    transform: translateY(0);
    animation: rise 500ms ease-out;
  }

  @keyframes rise {
    from {
      opacity: 0;
      transform: translateY(10px);
    }
    to {
      opacity: 1;
      transform: translateY(0);
    }
  }
}

@media (max-width: 420px) {
  .calc {
    padding: 18px;
  }

  .calc__display {
    font-size: 40px;
  }

  .key {
    height: 58px;
    border-radius: 16px;
  }
}