@import url('https://fonts.googleapis.com/css2?family=Space+Grotesk:wght@400;600;700&display=swap');

:root {
  color-scheme: light;
  --ink: #0f1a2b;
  --muted: #5d6b86;
  --glass: rgba(255, 255, 255, 0.6);
  --glass-border: rgba(255, 255, 255, 0.7);
  --shadow: rgba(18, 38, 77, 0.2);
  --accent: #ff6f4f;
  --accent-dark: #e2553b;
  --key: rgba(255, 255, 255, 0.8);
  --key-ghost: rgba(255, 255, 255, 0.45);
}

* {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  font-family: 'Space Grotesk', 'Segoe UI', sans-serif;
  color: var(--ink);
  background: radial-gradient(circle at top, #f7f0ff 0%, #dce9ff 40%, #f8f9ff 100%);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 32px 16px;
}

body::before,
body::after {
  content: '';
  position: fixed;
  width: 380px;
  height: 380px;
  border-radius: 50%;
  z-index: -1;
  filter: blur(0px);
}

body::before {
  top: -120px;
  left: -80px;
  background: radial-gradient(circle, rgba(255, 111, 79, 0.25), transparent 65%);
}

body::after {
  bottom: -120px;
  right: -60px;
  background: radial-gradient(circle, rgba(91, 158, 255, 0.35), transparent 70%);
}

.app {
  width: min(920px, 100%);
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 32px;
  align-items: center;
  animation: float-in 0.8s ease-out both;
}

.app__header {
  padding: 12px 8px;
}

.app__eyebrow {
  font-weight: 700;
  letter-spacing: 0.3em;
  font-size: 0.7rem;
  text-transform: uppercase;
  color: var(--muted);
  margin: 0 0 16px 0;
}

.app__title {
  margin: 0 0 12px 0;
  font-size: clamp(2rem, 3vw, 3rem);
}

.app__subtitle {
  margin: 0;
  color: var(--muted);
  font-size: 1rem;
  max-width: 320px;
}

.calculator {
  background: var(--glass);
  border: 1px solid var(--glass-border);
  border-radius: 24px;
  padding: 24px;
  box-shadow: 0 18px 40px var(--shadow);
  backdrop-filter: blur(16px);
  display: grid;
  gap: 20px;
}

.calculator__display {
  background: rgba(255, 255, 255, 0.7);
  border-radius: 18px;
  padding: 18px 20px;
  box-shadow: inset 0 1px 4px rgba(0, 0, 0, 0.08);
}

.calculator__history {
  font-size: 0.85rem;
  color: var(--muted);
  min-height: 18px;
}

.calculator__input {
  width: 100%;
  border: none;
  background: transparent;
  font-size: clamp(1.8rem, 3vw, 2.6rem);
  font-weight: 700;
  text-align: right;
  color: var(--ink);
  outline: none;
}

.calculator__keys {
  display: grid;
  grid-template-columns: repeat(4, minmax(0, 1fr));
  gap: 12px;
}

.key {
  border: none;
  border-radius: 16px;
  padding: 16px;
  font-size: 1.1rem;
  font-weight: 600;
  background: var(--key);
  color: var(--ink);
  box-shadow: 0 8px 18px rgba(15, 26, 43, 0.08);
  cursor: pointer;
  transition: transform 0.12s ease, box-shadow 0.12s ease;
}

.key:active {
  transform: translateY(2px) scale(0.98);
  box-shadow: 0 4px 10px rgba(15, 26, 43, 0.12);
}

.key--accent {
  background: linear-gradient(135deg, var(--accent), var(--accent-dark));
  color: #fff;
}

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

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

@keyframes float-in {
  from {
    opacity: 0;
    transform: translateY(16px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@media (max-width: 720px) {
  .app {
    grid-template-columns: 1fr;
  }

  .calculator {
    order: -1;
  }
}