:root {
  --bg-top: #edf4ff;
  --bg-bottom: #dce8ff;
  --surface: rgba(255, 255, 255, 0.45);
  --surface-strong: rgba(255, 255, 255, 0.72);
  --text-primary: #11243e;
  --text-muted: #5f6f86;
  --accent: #2f7cf6;
  --accent-strong: #1f64d4;
  --danger: #df5e75;
  --shadow: 0 22px 45px rgba(20, 42, 76, 0.24);
  --radius-xl: 30px;
  --radius-lg: 18px;
  --radius-md: 14px;
  --timing-fast: 160ms;
  --timing-medium: 260ms;
  --font-main: "Poppins", "Segoe UI", Tahoma, sans-serif;
  --orb-blue: rgba(76, 145, 255, 0.8);
  --orb-cyan: rgba(76, 210, 255, 0.78);
  --orb-lilac: rgba(150, 138, 255, 0.75);
}

*,
*::before,
*::after {
  box-sizing: border-box;
}

body {
  margin: 0;
  min-height: 100vh;
  min-height: 100dvh;
  font-family: var(--font-main);
  -webkit-text-size-adjust: 100%;
  background: linear-gradient(145deg, var(--bg-top), var(--bg-bottom));
  color: var(--text-primary);
  display: grid;
  place-items: center;
  overflow: hidden;
  position: relative;
}

body::before,
body::after {
  content: "";
  position: absolute;
  width: 320px;
  aspect-ratio: 1;
  border-radius: 50%;
  filter: blur(24px);
  z-index: 0;
  opacity: 0.55;
  animation: floatBlob 11s ease-in-out infinite;
}

body::before {
  top: -80px;
  left: -90px;
  background: #9ec1ff;
}

body::after {
  right: -100px;
  bottom: -90px;
  background: #c7dcff;
  animation-delay: -4.6s;
}

.ambient-bg {
  position: fixed;
  inset: -24vmax;
  pointer-events: none;
  z-index: 1;
}

.ambient-bg__orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(58px);
  opacity: 0.64;
  transform: translate3d(0, 0, 0);
  will-change: transform, opacity;
}

.ambient-bg__orb--1 {
  width: min(38vw, 480px);
  aspect-ratio: 1;
  left: 8%;
  top: 12%;
  background: radial-gradient(circle at 35% 35%, var(--orb-blue), transparent 70%);
  animation: driftOne 8.5s ease-in-out infinite, breathe 4.8s ease-in-out infinite;
}

.ambient-bg__orb--2 {
  width: min(32vw, 430px);
  aspect-ratio: 1;
  right: 7%;
  top: 18%;
  background: radial-gradient(circle at 50% 40%, var(--orb-cyan), transparent 72%);
  animation: driftTwo 9.8s ease-in-out infinite, breathe 5.2s ease-in-out infinite;
  animation-delay: -4.4s, -1.8s;
}

.ambient-bg__orb--3 {
  width: min(36vw, 460px);
  aspect-ratio: 1;
  right: 25%;
  bottom: 4%;
  background: radial-gradient(circle at 50% 50%, var(--orb-lilac), transparent 72%);
  animation: driftThree 7.9s ease-in-out infinite, breathe 4.6s ease-in-out infinite;
  animation-delay: -6.2s, -2.6s;
}

.app {
  width: min(100%, 430px);
  padding: 22px;
  padding-top: max(22px, env(safe-area-inset-top));
  padding-right: max(22px, env(safe-area-inset-right));
  padding-bottom: max(22px, env(safe-area-inset-bottom));
  padding-left: max(22px, env(safe-area-inset-left));
  position: relative;
  z-index: 3;
}

.calculator {
  border-radius: var(--radius-xl);
  border: 1px solid rgba(255, 255, 255, 0.7);
  background: var(--surface);
  box-shadow: var(--shadow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  padding: 24px;
  animation: cardIn 560ms cubic-bezier(0.2, 0.9, 0.25, 1);
  position: relative;
  overflow: hidden;
  z-index: 1;
}

.calculator::before {
  content: "";
  position: absolute;
  width: 140px;
  height: 140px;
  background: #00d9ff;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0;
  transition: opacity 0.3s ease;
  pointer-events: none;
  top: var(--y);
  left: var(--x);
  transform: translate(-50%, -50%);
}

.calculator * {
  position: relative;
  z-index: 2;
}

.calculator:hover::before {
  opacity: 0.8;
}

.calculator__header {
  display: flex;
  align-items: baseline;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.calculator__eyebrow {
  margin: 0;
  font-size: 0.78rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
  color: var(--text-muted);
  font-weight: 600;
}

.calculator__title {
  margin: 0;
  font-size: 1.35rem;
  font-weight: 700;
}

.display {
  border-radius: var(--radius-lg);
  background: var(--surface-strong);
  border: 1px solid rgba(255, 255, 255, 0.85);
  padding: 14px 16px;
  margin-bottom: 16px;
  text-align: right;
  transition: transform var(--timing-medium) ease, box-shadow var(--timing-medium) ease;
  box-shadow: inset 0 1px 0 rgba(255, 255, 255, 0.8);
}

.display:focus-within {
  transform: translateY(-1px);
}

.display__previous {
  margin: 0;
  min-height: 1.25rem;
  color: var(--text-muted);
  font-size: 0.95rem;
  font-weight: 600;
}

.display__current {
  margin: 6px 0 0;
  min-height: 2.8rem;
  font-size: clamp(2rem, 6.6vw, 2.9rem);
  font-weight: 700;
  letter-spacing: 0.015em;
  word-break: break-all;
}

.keys {
  display: grid;
  grid-template-columns: repeat(4, minmax(56px, 1fr));
  gap: 11px;
}

.btn {
  border: 0;
  border-radius: var(--radius-md);
  background: rgba(255, 255, 255, 0.78);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 1.1rem;
  font-weight: 650;
  min-height: 56px;
  cursor: pointer;
  transition: transform var(--timing-fast) ease, box-shadow var(--timing-fast) ease,
    background-color var(--timing-fast) ease, color var(--timing-fast) ease;
  box-shadow: 0 8px 18px rgba(16, 35, 62, 0.12);
}

.btn:hover {
  box-shadow: 0 10px 20px rgba(16, 35, 62, 0.16);
}

.btn:active,
.btn.is-key-pressed {
  transform: translateY(1px) scale(0.95);
  box-shadow: 0 3.5px 10px rgba(16, 35, 62, 0.15);
  border-radius: 18px;
}

.btn:focus-visible {
  outline: 3px solid rgba(47, 124, 246, 0.35);
  outline-offset: 2px;
}

.btn--function {
  background: rgba(159, 198, 255, 0.95);
  color: #000000;
}

.btn--operator {
  background: linear-gradient(165deg, var(--accent), var(--accent-strong));
  color: #fff;
  font-size: 1.25rem;
}

.btn--operator.is-selected {
  box-shadow: 0 0 0 3px rgba(47, 124, 246, 0.26), 0 8px 18px rgba(16, 35, 62, 0.19);
}

.btn--equal {
  background: linear-gradient(165deg, #ff7f6d, var(--danger));
  color: #fff;
  font-size: 1.3rem;
}

.btn--span-2 {
  grid-column: span 2;
}

.btn--span-4 {
  grid-column: 1 / -1;
}

.calculator__hint {
  margin: 14px 2px 0;
  font-size: 0.79rem;
  color: var(--text-muted);
  text-align: center;
}

.noscript-note {
  margin: 12px auto 0;
  max-width: 430px;
  text-align: center;
  color: #1e2f48;
  font-size: 0.88rem;
}

@media (max-width: 460px) {
  .app {
    padding: 14px;
    padding-top: max(14px, env(safe-area-inset-top));
    padding-right: max(14px, env(safe-area-inset-right));
    padding-bottom: max(14px, env(safe-area-inset-bottom));
    padding-left: max(14px, env(safe-area-inset-left));
  }

  .calculator {
    padding: 18px;
  }

  .keys {
    gap: 9px;
  }

  .btn {
    min-height: 52px;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation: none !important;
    transition: none !important;
  }
}

@keyframes cardIn {
  from {
    opacity: 0;
    transform: translateY(16px) scale(0.98);
  }
  to {
    opacity: 1;
    transform: translateY(0) scale(1);
  }
}

@keyframes floatBlob {
  0%,
  100% {
    transform: translate3d(0, 0, 0) scale(1);
  }
  50% {
    transform: translate3d(14px, -16px, 0) scale(1.03);
  }
}

@keyframes driftOne {
  0% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
  25% {
    transform: translate3d(18vw, -7vh, 0) scale(1.12) rotate(7deg);
  }
  50% {
    transform: translate3d(7vw, -17vh, 0) scale(1.18) rotate(12deg);
  }
  75% {
    transform: translate3d(-13vw, -6vh, 0) scale(1.08) rotate(5deg);
  }
  100% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
}

@keyframes driftTwo {
  0% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
  25% {
    transform: translate3d(-19vw, 8vh, 0) scale(0.92) rotate(-8deg);
  }
  50% {
    transform: translate3d(-5vw, 18vh, 0) scale(1.08) rotate(-13deg);
  }
  75% {
    transform: translate3d(15vw, 6vh, 0) scale(0.98) rotate(-6deg);
  }
  100% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
}

@keyframes driftThree {
  0% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
  25% {
    transform: translate3d(14vw, -16vh, 0) scale(1.13) rotate(9deg);
  }
  50% {
    transform: translate3d(23vw, -4vh, 0) scale(1.06) rotate(14deg);
  }
  75% {
    transform: translate3d(6vw, 12vh, 0) scale(0.96) rotate(6deg);
  }
  100% {
    transform: translate3d(0, 0, 0) scale(1) rotate(0deg);
  }
}

@keyframes breathe {
  0%,
  100% {
    opacity: 0.5;
  }
  50% {
    opacity: 0.82;
  }
}