:root {
  --bg: #cfe2e6;
  --panel: #ffffff;
  --line: #b8cbd0;
  --text: #15323a;
  --shadow: rgba(0,0,0,.06);

  /* black keys */
  --sharp-dark: #1f1f1f;
  --sharp-dark-2: #2b2b2b;
  --sharp-glow: rgba(255, 215, 0, 0.55);
}

* { box-sizing: border-box; }

body {
  margin: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans JP", sans-serif;
  background: var(--bg);
  color: var(--text);
}

.wrap {
  max-width: 760px;
  margin: 0 auto;
  padding: 18px 14px;
}

.headrow{
  display:flex;
  align-items:flex-start;
  justify-content:space-between;
  gap: 14px;
}

h1 {
  margin: 0 0 6px;
  font-size: 22px;
}

.sub {
  margin: 0;
  font-size: 13px;
  opacity: .9;
}

.controls {
  display:flex;
  align-items:center;
}

.toggle{
  border: 1px solid rgba(0,0,0,.12);
  background: rgba(255,255,255,.75);
  border-radius: 12px;
  padding: 10px 12px;
  cursor: pointer;
  box-shadow: 0 2px 10px var(--shadow);
  font-size: 13px;
  white-space: nowrap;
}
.toggle:hover{ filter: brightness(1.05); }

.kbd {
  display: inline-block;
  padding: 2px 6px;
  border: 1px solid var(--line);
  border-bottom-width: 2px;
  border-radius: 6px;
  background: rgba(255,255,255,.7);
  font-size: 12px;
}

#display {
  margin: 10px 0 14px;
  padding: 12px 14px;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 10px;
  box-shadow: 0 2px 10px var(--shadow);
  font-size: 22px;
  text-align: right;
  min-height: 52px;
  overflow-x: auto;
  white-space: nowrap;
}

/* =======================
   Pad base
======================= */
.pad {
  display: grid;
  gap: 10px;
  padding: 14px;
  background: rgba(255,255,255,.25);
  border: 1px solid rgba(255,255,255,.35);
  border-radius: 14px;
}

/* keys */
.key {
  position: relative;
  border: 1px solid var(--line);
  background: var(--panel);
  border-radius: 14px;
  padding: 12px 10px;
  cursor: pointer;
  box-shadow: 0 2px 10px var(--shadow);
  transition: transform .06s ease, filter .06s ease, box-shadow .06s ease;
  user-select: none;
  min-height: 72px;

  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 6px;
}

.key:hover { filter: brightness(1.05); }

/* black keys */
.key.sharp {
  background: linear-gradient(to bottom, var(--sharp-dark-2), var(--sharp-dark));
  color: #f2f2f2;
  border-color: #111;
}
.key.sharp:hover { filter: brightness(1.15); }

.key .main {
  font-size: 28px;
  font-weight: 800;
  line-height: 1;
}

.key .main.tiny{ font-size: 14px; font-weight: 800; }

.key .subnote {
  font-size: 13px;
  opacity: .78;
  line-height: 1;
}

.key.sharp .subnote { color: #ddd; opacity: .92; }
.key .subnote small { font-size: 11px; opacity: .75; }
.key.sharp .subnote small { color:#bbb; opacity: .9; }

/* corner label */
.corner{
  position:absolute;
  top:8px;
  left:10px;
  font-size: 12px;
  font-weight: 800;
  opacity: .85;
}
.subcorner{
  font-weight: 700;
  opacity: .5;
}

/* pressed feedback */
.key.active {
  transform: scale(0.95);
  box-shadow:
    0 0 0 2px rgba(255,255,255,0.35),
    0 10px 22px rgba(0,0,0,0.35),
    inset 0 0 16px rgba(255,255,255,0.25);
}
.key.sharp.active {
  box-shadow:
    0 0 0 2px var(--sharp-glow),
    0 12px 26px rgba(0,0,0,0.5),
    inset 0 0 18px rgba(255,215,0,0.3);
}

/* disabled NumLock */
.key.is-disabled{
  cursor: default;
  filter: grayscale(0.3);
  opacity: .85;
}
.key.is-disabled:hover{ filter: grayscale(0.3); }
.key.is-disabled .corner{
  font-size: 18px;
  opacity: 0.9;
}
.key.is-disabled::after{
  content:"";
  position:absolute;
  inset: 12px;
  border-radius: 12px;
  border: 2px solid rgba(255,255,255,0.15);
  pointer-events:none;
}

/* =======================
   Layouts
======================= */

/* SIMPLE: 4x4 only */
.pad.layout-simple{
  grid-template-columns: repeat(4, 1fr);
  grid-template-areas:
    "k7 k8 k9 kdiv"
    "k4 k5 k6 kmul"
    "k1 k2 k3 ksub"
    "k0 kclear keq kadd";
}

/* PRO: like photo (5 rows, + and Enter are tall, 0 is wide) */
.pad.layout-pro{
  grid-template-columns: repeat(4, 1fr);
  grid-template-areas:
    "knum kdiv kmul ksub"
    "k7   k8   k9   kadd"
    "k4   k5   k6   kadd"
    "k1   k2   k3   kenter"
    "k0   k0   kdot kenter";
}

/* area assignments */
.k-numlock{ grid-area: knum; }
.k-div{ grid-area: kdiv; }
.k-mul{ grid-area: kmul; }
.k-sub{ grid-area: ksub; }
.k-add{ grid-area: kadd; }
.k-enter{ grid-area: kenter; }
.k-dot{ grid-area: kdot; }

.k-7{ grid-area: k7; }
.k-8{ grid-area: k8; }
.k-9{ grid-area: k9; }
.k-4{ grid-area: k4; }
.k-5{ grid-area: k5; }
.k-6{ grid-area: k6; }
.k-1{ grid-area: k1; }
.k-2{ grid-area: k2; }
.k-3{ grid-area: k3; }
.k-0{ grid-area: k0; }
.k-clear{ grid-area: kclear; }
.k-eq{ grid-area: keq; }

/* In SIMPLE layout, hide keys not part of 4x4 */
.pad.layout-simple .k-numlock,
.pad.layout-simple .k-dot,
.pad.layout-simple .k-enter{
  display:none;
}


/* Make + and Enter look taller in PRO layout (optional but satisfying) */
.pad.layout-pro .k-add .main,
.pad.layout-pro .k-enter .main{
  font-size: 24px;
}
.pad.layout-pro .k-enter .subnote{ opacity: .85; }

/* =======================
   Info section
======================= */
.note {
  margin-top: 18px;
  padding: 14px;
  background: rgba(255,255,255,.55);
  border: 1px solid rgba(255,255,255,.55);
  border-radius: 14px;
}

.note h2 {
  margin: 0 0 8px;
  font-size: 16px;
}

.note ul {
  margin: 0;
  padding-left: 18px;
}

.small {
  margin: 10px 0 0;
  font-size: 12px;
  opacity: .85;
}


/* Safety: In PRO layout, never show '=' (it should be Enter key only) */
.pad.layout-pro .k-eq{
  display:none !important;
}

/* Safety: In SIMPLE layout, never show the physical Enter key (hidden key) */
.pad.layout-simple .k-enter{
  display:none !important;
}


/* PRO layout: hide Clear button (C) for sure */
.pad.layout-pro .k-clear,
#pad.layout-pro .k-clear,
.pad.layout-pro .key[data-key="clear"],
#pad.layout-pro .key[data-key="clear"]{
  display: none !important;
}

.contact-mini{
  margin-top: 10px;
  padding-top: 10px;
  border-top: 1px dashed rgba(0, 0, 0, 0.0);
  text-align: center;
  font-size: 16px;
  opacity: .7;
}

.contact-mini a{
  color: inherit;
  text-decoration: underline;
}