#tool-body {
  --primary: #4f46e5;
  --primary-hover: #4338ca;
  --card-bg: #fff;
  --card-border: #e5e7eb;
  --text: #1f2937;
  --text-muted: #6b7280;
  --display-bg: #e4e9d4;
  --display-expr: #5b6644;
  --display-res: #2a3218;
  --display-err: #fca5a5;
  --key-bg: #f3f4f6;
  --key-bg-hover: #e5e7eb;
  --key-text: #1f2937;
  --key-sci: #eef2ff;
  --key-sci-hover: #e0e7ff;
  --key-sci-text: #3730a3;
  --key-op: #e0e7ff;
  --key-op-hover: #c7d2fe;
  --key-op-text: #3730a3;
  --key-ac-bg: #fee2e2;
  --key-ac-hover: #fecaca;
  --key-ac-text: #b91c1c;
  --key-eq-bg: #4f46e5;
  --key-eq-hover: #4338ca;
  --key-eq-text: #fff;
  --seg-bg: #f3f4f6;
  --shadow: 0 10px 28px rgba(15, 23, 42, 0.08);
  --hist-hover: #f5f3ff;
  --mode-off: #9ca3af;
  width: 100%;
  max-width: 736px;
  margin: 0 auto;
  padding-top: 4px;
  padding-bottom:20px;
  color: var(--text);
  font-family: "Segoe UI", "PingFang SC", "Microsoft YaHei", sans-serif;
  outline: none;
}
#tool-body.is-sci-layout {
  max-width: 816px;
}
.theme-dark-mode #tool-body {
  --card-bg: #252528;
  --card-border: #3a3a3e;
  --text: #e5e7eb;
  --text-muted: #9ca3af;
  --display-bg: #0b0b12;
  --display-expr: #c4a06a;
  --display-res: #ffcc66;
  --key-bg: #323236;
  --key-bg-hover: #3e3e44;
  --key-text: #e5e7eb;
  --key-sci: #2a2a40;
  --key-sci-hover: #343456;
  --key-sci-text: #c7d2fe;
  --key-op: #2e2e4a;
  --key-op-hover: #3a3a5c;
  --key-op-text: #c7d2fe;
  --key-ac-bg: #3f1d1d;
  --key-ac-hover: #4e2424;
  --key-ac-text: #fca5a5;
  --key-eq-bg: #6366f1;
  --key-eq-hover: #4f46e5;
  --seg-bg: #323236;
  --shadow: 0 10px 28px rgba(0, 0, 0, 0.35);
  --hist-hover: #2c2c38;
}
#tool-body .calc-wrap {
  display: flex;
  justify-content: center;
  align-items: flex-start;
  gap: 16px;
}
#tool-body .calc-panel,
#tool-body .hist-panel {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 16px;
  box-shadow: var(--shadow);
  overflow: hidden;
  box-sizing: border-box;
}
#tool-body .calc-panel {
  width: 420px;
  max-width: 60%;
  flex: none;
}
#tool-body.is-sci-layout .calc-panel {
  width: 500px;
}
#tool-body .hist-panel {
  width: 300px;
  max-width: calc(40% - 20px);
  flex: none;
}
#tool-body .calc-appbar {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding: 12px 14px;
}
#tool-body .layout-seg {
  display: inline-flex;
  background: var(--seg-bg);
  border-radius: 10px;
  padding: 3px;
}
#tool-body .layout-btn {
  border: 0;
  background: transparent;
  color: var(--text-muted);
  font-size: 13px;
  font-weight: 700;
  padding: 6px 14px;
  border-radius: 8px;
  cursor: pointer;
  line-height: 1.4;
}
#tool-body .layout-btn.is-on {
  background: var(--card-bg);
  color: var(--text);
  box-shadow: 0 1px 3px rgba(15, 23, 42, 0.12);
}
.theme-dark-mode #tool-body .layout-btn.is-on {
  background: #3a3a40;
  box-shadow: none;
}
#tool-body .calc-display {
  background: var(--display-bg);
  padding: 14px 16px 16px;
  border-radius: 10px;
  margin: 1px 12px;
}
#tool-body .calc-toolbar {
  display: none;
}
#tool-body.is-sci-layout .calc-toolbar {
  display: flex;
  align-items: center;
  margin-bottom: 10px;
}
#tool-body .calc-angle {
  display: inline-flex;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 8px;
  padding: 2px;
}
#tool-body .angle-btn {
  border: 0;
  background: transparent;
  color: var(--mode-off);
  font-size: 12px;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 4px 10px;
  border-radius: 6px;
  cursor: pointer;
  line-height: 1.4;
}
#tool-body .angle-btn.is-on {
  background: var(--primary);
  color: #fff;
}
#tool-body .calc-icon-btn {
  width: 32px;
  height: 32px;
  border: 0;
  border-radius: 8px;
  background: var(--seg-bg);
  color: var(--text-muted);
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}
#tool-body .calc-icon-btn:hover {
  background: var(--key-bg-hover);
  color: var(--text);
}
#tool-body #calc-expr {
  width: 100%;
  border: 0;
  background: transparent;
  color: var(--display-expr);
  font-size: 18px;
  line-height: 1.4;
  outline: none;
  box-shadow: none;
  padding: 0;
  margin: 0 0 6px;
  font-family: Consolas, "SF Mono", Menlo, monospace;
  caret-color: #a5b4fc;
}
#tool-body #calc-expr::placeholder {
  color: #6b7280;
}
#tool-body .calc-result {
  min-height: 30px;
  font-size: 36px;
  font-weight: 700;
  line-height: 30px;
  color: var(--display-res);
  font-family: Consolas, "SF Mono", Menlo, monospace;
  font-variant-numeric: tabular-nums;
  word-break: break-all;
  text-align: right;
}
#tool-body .calc-result.is-error {
  color: var(--display-err);
  font-size: 18px;
  font-weight: 600;
}
#tool-body .calc-keys {
  padding: 12px;
}
#tool-body .calc-sci,
#tool-body .calc-pad {
  display: grid;
  gap: 8px;
}
#tool-body .calc-sci {
  display: none;
  grid-template-columns: repeat(5, minmax(0, 1fr));
  margin-bottom: 8px;
}
#tool-body.is-sci-layout .calc-sci {
  display: grid;
}
#tool-body .calc-pad {
  grid-template-columns: repeat(4, minmax(0, 1fr));
}
#tool-body .calc-key {
  border: 0;
  border-radius: 12px;
  min-height: 56px;
  padding: 4px 2px;
  font-size: 20px;
  font-weight: 650;
  cursor: pointer;
  background: var(--key-bg);
  color: var(--key-text);
  transition: background 0.12s, transform 0.08s;
  touch-action: manipulation;
  user-select: none;
  -webkit-user-select: none;
  line-height: 1.15;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 1px;
}
#tool-body.is-sci-layout .calc-key {
  min-height: 46px;
  font-size: 16px;
}
#tool-body .calc-key .k-sub {
  font-size: 12px;
  font-weight: 500;
  opacity: 0.72;
  line-height: 1;
  display: inline-block;
  transform: scale(0.9);
  transform-origin: center top;
  height: 9px;
}
#tool-body .calc-key:hover {
  background: var(--key-bg-hover);
}
#tool-body .calc-key:active {
  transform: scale(0.96);
}
#tool-body .calc-key.is-sci {
  background: var(--key-sci);
  color: var(--key-sci-text);
  font-size: 15px;
  min-height: 48px;
}
#tool-body .calc-key.is-sci:hover {
  background: var(--key-sci-hover);
}
#tool-body .calc-key.is-op {
  background: var(--key-op);
  color: var(--key-op-text);
  font-size: 22px;
}
#tool-body.is-sci-layout .calc-key.is-op {
  font-size: 18px;
}
#tool-body .calc-key.is-op:hover {
  background: var(--key-op-hover);
}
#tool-body .calc-key.is-ac {
  background: var(--key-ac-bg);
  color: var(--key-ac-text);
  font-size: 15px;
}
#tool-body .calc-key.is-ac:hover {
  background: var(--key-ac-hover);
}
#tool-body .calc-key.is-eq {
  background: var(--key-eq-bg);
  color: var(--key-eq-text);
  font-size: 26px;
}
#tool-body .calc-key.is-eq:hover {
  background: var(--key-eq-hover);
}
#tool-body .calc-hint {
  padding: 0 14px 12px;
  font-size: 12px;
  color: var(--text-muted);
  line-height: 1.6;
}
#tool-body .hint-sci {
  display: none;
}
#tool-body.is-sci-layout .hint-basic {
  display: none;
}
#tool-body.is-sci-layout .hint-sci {
  display: block;
}
#tool-body .hist-panel {
  padding: 14px 8px 10px;
  display: flex;
  flex-direction: column;
}
#tool-body .hist-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 10px;
}
#tool-body .hist-title {
  font-size: 15px;
  font-weight: 700;
  display: flex;
  align-items: center;
  gap: 8px;
}
#tool-body .hist-title i {
  color: var(--primary);
}
#tool-body .hist-clear {
  border: 0;
  background: transparent;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 12px;
  padding: 4px 6px;
  border-radius: 6px;
}
#tool-body .hist-clear:hover {
  color: var(--text);
  background: var(--key-bg);
}
#tool-body .hist-list {
  height: 471px;
  overflow: auto;
  display: flex;
  flex-direction: column;
  gap: 8px;
  padding: 5px;
}
#tool-body .hist-item {
  display: block;
  width: 100%;
  text-align: left;
  border: 1px solid var(--card-border);
  background: transparent;
  border-radius: 10px;
  cursor: pointer;
  color: var(--text);
  padding: 10px 12px;
}
#tool-body .hist-item:hover {
  background: var(--hist-hover);
  border-color: var(--primary);
}
#tool-body .hist-expr {
  display: block;
  font-size: 12px;
  color: var(--text-muted);
  word-break: break-all;
  font-family: Consolas, "SF Mono", Menlo, monospace;
}
#tool-body .hist-res {
  display: block;
  margin-top: 4px;
  font-size: 16px;
  font-weight: 700;
  font-family: Consolas, "SF Mono", Menlo, monospace;
  word-break: break-all;
}
#tool-body .hist-empty {
  text-align: center;
  color: var(--text-muted);
  padding: 36px 8px;
  font-size: 13px;
  line-height: 1.6;
}
#tool-body .hist-empty i {
  display: block;
  font-size: 28px;
  margin-bottom: 8px;
  opacity: 0.7;
}
@media (max-width: 768px) {
  #tool-body,
  #tool-body.is-sci-layout {
    width: 100%;
  }
  #tool-body .calc-wrap {
    flex-direction: column;
    gap: 12px;
  }
  #tool-body .calc-panel,
  #tool-body.is-sci-layout .calc-panel,
  #tool-body .hist-panel {
    width: 100%;
    max-width: 100%;
  }
  #tool-body .calc-key {
    min-height: 50px;
    border-radius: 10px;
    font-size: 18px;
  }
  #tool-body.is-sci-layout .calc-key,
  #tool-body .calc-key.is-sci {
    min-height: 32px;
    font-size: 13px;
  }
  #tool-body .calc-result {
    font-size: 28px;
  }
  #tool-body .hist-list {
    height: 240px;
  }
  #tool-body .layout-btn {
    padding: 6px 10px;
  }
}