:root {
  --bg: #000;
  --panel: #1c1c1e;
  --display-fg: #ffffff;
  --secondary-fg: #8e8e93;
  --key-digit: #333336;
  --key-digit-active: #737376;
  --key-fn: #a5a5a5;
  --key-fn-active: #d9d9d9;
  --key-op: #ff9f0a;
  --key-op-active: #ffc777;
  --accent: #ff9f0a;
  --pill-bg: #2c2c2e;
  --pill-active: #3a3a3c;
  --gap: 12px;
  --radius: 999px;
}

* { box-sizing: border-box; -webkit-tap-highlight-color: transparent; }

html, body {
  margin: 0;
  height: 100%;
  background: var(--bg);
  color: var(--display-fg);
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  overscroll-behavior: none;
}

body {
  display: flex;
  justify-content: center;
  user-select: none;
  -webkit-user-select: none;
}

.app {
  width: 100%;
  max-width: 480px;
  min-height: 100%;
  height: 100dvh;
  display: flex;
  flex-direction: column;
  padding: calc(env(safe-area-inset-top) + 8px) 16px calc(env(safe-area-inset-bottom) + 12px);
  gap: 10px;
}

/* ---- Mode switch ---- */
.modes {
  display: flex;
  background: var(--panel);
  border-radius: 12px;
  padding: 4px;
  gap: 4px;
  flex: 0 0 auto;
}
.mode-btn {
  flex: 1;
  border: 0;
  background: transparent;
  color: var(--secondary-fg);
  font-size: 15px;
  font-weight: 600;
  padding: 9px 0;
  border-radius: 9px;
  cursor: pointer;
  transition: background .15s, color .15s;
}
.mode-btn.is-active {
  background: var(--key-op);
  color: #000;
}

/* ---- Convert bar ---- */
.convert-bar {
  display: flex;
  align-items: center;
  gap: 8px;
  flex: 0 0 auto;
}
.convert-bar[hidden] { display: none; }
.pill {
  flex: 1;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  background: var(--pill-bg);
  border: 0;
  color: var(--display-fg);
  padding: 12px 10px;
  border-radius: 14px;
  font-size: 17px;
  font-weight: 600;
  cursor: pointer;
}
.pill:active { background: var(--pill-active); }
.pill-flag { font-size: 20px; line-height: 1; }
.swap {
  flex: 0 0 auto;
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: 0;
  background: var(--pill-bg);
  color: var(--key-op);
  font-size: 20px;
  cursor: pointer;
}
.swap:active { background: var(--pill-active); }

/* ---- Display ---- */
.display {
  flex: 1 1 auto;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  align-items: flex-end;
  text-align: right;
  padding: 6px 6px 4px;
  min-height: 96px;
  overflow: hidden;
}
.secondary {
  color: var(--secondary-fg);
  font-size: clamp(18px, 6vw, 26px);
  font-weight: 400;
  min-height: 30px;
  max-width: 100%;
  overflow: hidden;
  text-overflow: ellipsis;
  white-space: nowrap;
}
.secondary.converted {
  color: var(--accent);
  font-weight: 500;
}
.primary {
  color: var(--display-fg);
  font-size: clamp(56px, 20vw, 88px);
  font-weight: 300;
  line-height: 1.05;
  max-width: 100%;
  overflow: hidden;
  text-overflow: clip;
  white-space: nowrap;
  letter-spacing: -1px;
}
.rate-note {
  color: var(--secondary-fg);
  font-size: 12px;
  margin-top: 6px;
  font-weight: 400;
}
.rate-note.offline { color: #ff9f0a; }
.rate-note.error { color: #ff453a; }

/* ---- Keypad ---- */
.keys {
  flex: 0 0 auto;
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: var(--gap);
}
.key {
  border: 0;
  border-radius: var(--radius);
  aspect-ratio: 1 / 1;
  background: var(--key-digit);
  color: var(--display-fg);
  font-size: clamp(24px, 8vw, 34px);
  font-weight: 400;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background .1s, filter .1s;
}
.key:active { background: var(--key-digit-active); }
.key-fn {
  background: var(--key-fn);
  color: #000;
  font-weight: 500;
}
.key-fn:active { background: var(--key-fn-active); }
.key-op {
  background: var(--key-op);
  color: #fff;
  font-size: clamp(28px, 9vw, 40px);
}
.key-op:active { background: var(--key-op-active); }
.key-op.selected {
  background: #fff;
  color: var(--key-op);
}
.key-zero {
  grid-column: span 2;
  aspect-ratio: auto;
  justify-content: flex-start;
  padding-left: 8%;
}

/* ---- Currency sheet ---- */
.sheet {
  position: fixed;
  inset: 0;
  background: rgba(0, 0, 0, 0.5);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  z-index: 20;
}
.sheet[hidden] { display: none; }
.sheet-panel {
  width: 100%;
  max-width: 480px;
  max-height: 82dvh;
  background: var(--panel);
  border-radius: 20px 20px 0 0;
  padding: 12px 16px calc(env(safe-area-inset-bottom) + 16px);
  display: flex;
  flex-direction: column;
  animation: slideup .22s ease;
}
@keyframes slideup { from { transform: translateY(100%); } to { transform: translateY(0); } }
.sheet-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 4px 0 10px;
}
.sheet-title { font-size: 17px; font-weight: 600; }
.sheet-close {
  border: 0;
  background: var(--pill-bg);
  color: var(--display-fg);
  width: 30px;
  height: 30px;
  border-radius: 50%;
  font-size: 14px;
  cursor: pointer;
}
.sheet-search {
  background: #2c2c2e;
  border: 0;
  border-radius: 10px;
  padding: 11px 14px;
  color: #fff;
  font-size: 16px;
  margin-bottom: 8px;
  outline: none;
}
.sheet-search::placeholder { color: #8e8e93; }
.sheet-list {
  list-style: none;
  margin: 0;
  padding: 0;
  overflow-y: auto;
  -webkit-overflow-scrolling: touch;
}
.sheet-item {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 12px 6px;
  border-bottom: 1px solid #2c2c2e;
  cursor: pointer;
}
.sheet-item:active { background: #2c2c2e; }
.sheet-item.is-selected { color: var(--accent); }
.sheet-item-flag { font-size: 24px; width: 30px; text-align: center; }
.sheet-item-code { font-weight: 600; width: 46px; }
.sheet-item-name { color: var(--secondary-fg); font-size: 14px; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.sheet-item.is-selected .sheet-item-name { color: var(--accent); opacity: .8; }

@media (max-height: 640px) {
  .primary { font-size: clamp(44px, 15vw, 64px); }
  .key { font-size: 26px; }
  :root { --gap: 9px; }
}