:root {
  --bg: #0b0c0f;
  --panel: #14161c;
  --line: #2a2e38;
  --text: #ece8df;
  --muted: #9a9488;
  --accent: #7ee0c8;
  --accent-dim: #2a5c52;
  --op: #e8b86d;
  --danger: #f0a5a0;
  --key: #1c2029;
  --key-hover: #262b36;
}

* { box-sizing: border-box; }
[hidden] { display: none !important; }
html, body { margin: 0; min-height: 100%; background: var(--bg); color: var(--text); }
body {
  font-family: Outfit, system-ui, sans-serif;
  min-height: 100dvh;
}

.page {
  max-width: 980px;
  margin: 0 auto;
  padding: 32px 20px 48px;
}

.top {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
  gap: 16px;
  margin-bottom: 28px;
}
.kicker {
  margin: 0 0 8px;
  font-size: 12px;
  letter-spacing: 0.16em;
  text-transform: uppercase;
  color: var(--accent);
}
h1 {
  font-family: Fraunces, Georgia, serif;
  font-weight: 500;
  font-size: clamp(32px, 5vw, 48px);
  margin: 0;
  line-height: 1;
}
.toggles { display: flex; gap: 8px; }
.chip, .ghost, button {
  font-family: inherit;
}
.chip {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 14px;
  cursor: pointer;
}
.chip[aria-pressed="true"] {
  color: var(--bg);
  background: var(--accent);
  border-color: var(--accent);
}
.ghost {
  background: none;
  border: 0;
  color: var(--muted);
  cursor: pointer;
  padding: 0;
}
.ghost:hover { color: var(--danger); }

.shell {
  display: grid;
  grid-template-columns: 260px 1fr;
  gap: 20px;
  align-items: start;
}

.history, .calc {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 20px;
}
.history { padding: 18px 18px 12px; min-height: 420px; }
.history-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
}
.history-head h2 { margin: 0; font-size: 15px; font-weight: 500; }
.history-list {
  list-style: none;
  margin: 0;
  padding: 0;
  display: grid;
  gap: 8px;
  max-height: 520px;
  overflow: auto;
}
.history-list li {
  margin: 0;
}
.history-list button {
  width: 100%;
  text-align: left;
  background: #10131a;
  border: 1px solid var(--line);
  border-radius: 12px;
  color: inherit;
  padding: 10px 12px;
  cursor: pointer;
}
.history-list .sum { color: var(--muted); font-size: 12px; }
.history-list .val {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: 16px;
  margin-top: 2px;
}
.muted { color: var(--muted); font-size: 13px; }

.calc { padding: 18px; }
.screen {
  background: #0b0c0f;
  border-radius: 16px;
  padding: 18px 18px 14px;
  margin-bottom: 14px;
  min-height: 96px;
}
.expr {
  min-height: 20px;
  color: var(--muted);
  font-size: 14px;
  text-align: right;
}
.display {
  font-family: "JetBrains Mono", ui-monospace, monospace;
  font-size: clamp(32px, 7vw, 48px);
  text-align: right;
  word-break: break-all;
  line-height: 1.15;
}
.display.error { color: var(--danger); font-size: 28px; }

.keys { display: grid; gap: 10px; }
.sci, .pad {
  display: grid;
  gap: 8px;
}
.sci { grid-template-columns: repeat(4, 1fr); }
.pad { grid-template-columns: repeat(4, 1fr); }
.sci.hidden { display: none; }

.keys button {
  height: 56px;
  border: 0;
  border-radius: 14px;
  background: var(--key);
  color: var(--text);
  font-size: 18px;
  font-weight: 500;
  cursor: pointer;
}
.keys button:hover { background: var(--key-hover); }
.keys button:active { transform: translateY(1px); }
.keys .fn { color: var(--accent); }
.keys .op { color: var(--op); }
.keys .eq {
  background: var(--accent);
  color: var(--bg);
}
.keys .eq:hover { background: #9aead8; }
.sci button { height: 44px; font-size: 14px; color: var(--muted); }
.hint { color: var(--muted); font-size: 12px; margin: 12px 4px 0; }

.tabs {
  display: flex;
  gap: 8px;
  margin: -8px 0 20px;
  flex-wrap: wrap;
}
.tabs button {
  background: transparent;
  color: var(--muted);
  border: 1px solid var(--line);
  border-radius: 999px;
  padding: 8px 16px;
  cursor: pointer;
}
.tabs button[aria-selected="true"] {
  color: var(--bg);
  background: var(--accent);
  border-color: var(--accent);
}

.shell.hidden { display: none; }
.tool { margin-top: 0; }
.tool.hidden { display: none; }
.tool-card {
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 20px;
  padding: 22px;
}
.tool-card h2 {
  font-family: Fraunces, Georgia, serif;
  font-weight: 500;
  font-size: 28px;
  margin: 0 0 8px;
}
.field {
  display: grid;
  gap: 6px;
  margin: 14px 0;
  font-size: 13px;
  color: var(--muted);
}
.field input, .field select {
  font-family: "JetBrains Mono", Outfit, sans-serif;
  font-size: 16px;
  color: var(--text);
  background: #0b0c0f;
  border: 1px solid var(--line);
  border-radius: 12px;
  padding: 12px 14px;
}
.field input:focus, .field select:focus {
  outline: 2px solid var(--accent-dim);
}
.row2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 12px;
}
.check {
  display: flex;
  align-items: center;
  gap: 10px;
  margin: 18px 0 8px;
  color: var(--muted);
  font-size: 14px;
}
.result {
  margin: 18px 0 0;
  padding: 16px;
  background: #0b0c0f;
  border-radius: 14px;
  display: grid;
  gap: 10px;
}
.result div {
  display: flex;
  justify-content: space-between;
  gap: 16px;
  font-size: 14px;
}
.result dt { color: var(--muted); margin: 0; }
.result dd {
  margin: 0;
  font-family: "JetBrains Mono", ui-monospace, monospace;
  text-align: right;
}
.result .hi dd { color: var(--accent); font-size: 18px; }

@media (max-width: 800px) {
  .shell { grid-template-columns: 1fr; }
  .history { min-height: 0; order: 2; }
  .history-list { max-height: 220px; }
  .page { padding: 20px 14px 32px; }
  .row2 { grid-template-columns: 1fr; }
  .top { flex-direction: column; align-items: flex-start; }
}