/* Apple-style online calculator */

:root{
  --bg: #f2f2f2;
  --panel: rgba(255,255,255,.78);
  --panel-border: rgba(0,0,0,.08);

  --key: #d4d4d2;
  --key-hover: #e0e0de;
  --key-active: #c0c0be;

  --key-operator: #e7e7e5;
  --key-operator-hover: #ededeb;
  --key-operator-active: #d8d8d6;

  --key-equals: #ff9f0a;
  --key-equals-hover: #ffb12e;
  --key-equals-active: #e98d08;

  --text: #1c1c1c;
  --muted: rgba(0,0,0,.45);

  --shadow-lg: 0 24px 60px rgba(0,0,0,.18);
  --shadow-md: 0 10px 26px rgba(0,0,0,.12);
}

*{ box-sizing: border-box; }
html, body{ height: 100%; }

body{
  margin: 0;
  font-family: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
  background:
    radial-gradient(1200px 600px at 20% 15%, rgba(255,255,255,.9), rgba(255,255,255,0) 55%),
    radial-gradient(900px 450px at 70% 80%, rgba(255,255,255,.65), rgba(255,255,255,0) 60%),
    linear-gradient(180deg, #ededed 0%, var(--bg) 100%);
  color: var(--text);
}

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

.calculator{
  width: min(380px, 92vw);
  border-radius: 26px;
  background: var(--panel);
  border: 1px solid var(--panel-border);
  box-shadow: var(--shadow-lg);
  overflow: hidden;
  backdrop-filter: blur(10px);
}

.display{
  padding: 22px 22px 18px;
  background: linear-gradient(180deg, rgba(255,255,255,.65) 0%, rgba(255,255,255,.42) 100%);
}

.expression{
  height: 22px;
  font-size: 14px;
  color: var(--muted);
  letter-spacing: .2px;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.result{
  margin-top: 6px;
  text-align: right;
  font-variant-numeric: tabular-nums;
  font-size: clamp(34px, 7.2vw, 50px);
  line-height: 1.1;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}

.keypad{
  padding: 18px;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
}

.key{
  appearance: none;
  border: 0;
  border-radius: 16px;
  height: 58px;
  background: linear-gradient(180deg, rgba(255,255,255,.55) 0%, rgba(255,255,255,0) 40%), var(--key);
  color: #1d1d1d;
  font-size: 22px;
  font-weight: 600;
  border: 1px solid rgba(0,0,0,.06);
  box-shadow:
    inset 0 1px rgba(255,255,255,.55),
    0 10px 26px rgba(0,0,0,.12);
  cursor: pointer;
  transition: transform .06s ease, background-color .12s ease, box-shadow .12s ease;
}

.key:hover{
  background: linear-gradient(180deg, rgba(255,255,255,.6) 0%, rgba(255,255,255,0) 40%), var(--key-hover);
}

.key:active{
  background: linear-gradient(180deg, rgba(255,255,255,.45) 0%, rgba(255,255,255,0) 40%), var(--key-active);
  transform: translateY(1px);
  box-shadow:
    inset 0 1px rgba(255,255,255,.25),
    0 6px 14px rgba(0,0,0,.12);
}

.key--operator{
  background: linear-gradient(180deg, rgba(255,255,255,.5) 0%, rgba(255,255,255,0) 40%), var(--key-operator);
}
.key--operator:hover{ background: var(--key-operator-hover); }
.key--operator:active{ background: var(--key-operator-active); }

.key--equals{
  background: linear-gradient(180deg, rgba(255,255,255,.35) 0%, rgba(255,255,255,0) 35%), var(--key-equals);
  color: #111;
  font-weight: 800;
}
.key--equals:hover{ background: var(--key-equals-hover); }
.key--equals:active{ background: var(--key-equals-active); }

/* Preserve the glossy gradient for hover/active states */
.key--operator:hover{
  background: linear-gradient(180deg, rgba(255,255,255,.6) 0%, rgba(255,255,255,0) 40%), var(--key-operator-hover);
}
.key--operator:active{
  background: linear-gradient(180deg, rgba(255,255,255,.45) 0%, rgba(255,255,255,0) 40%), var(--key-operator-active);
}
.key--equals:hover{
  background: linear-gradient(180deg, rgba(255,255,255,.45) 0%, rgba(255,255,255,0) 35%), var(--key-equals-hover);
}
.key--equals:active{
  background: linear-gradient(180deg, rgba(255,255,255,.25) 0%, rgba(255,255,255,0) 35%), var(--key-equals-active);
}

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

.key:focus-visible{
  outline: 3px solid rgba(0,0,0,.22);
  outline-offset: 2px;
}

/* Mobile scaling */
@media (max-width: 380px){
  .keypad{ gap: 10px; padding: 16px; }
  .key{ height: 54px; border-radius: 14px; font-size: 20px; }
  .display{ padding: 18px 18px 14px; }
}