.calculator-section {
  padding: 8px 0 64px;
}
.calculator-layout {
  display: flex;
  align-items: flex-start;
  gap: 24px;
}

/* ===== Calculator card ===== */
.calculator-card {
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 28px;
  width: 640px;
  max-width: 100%;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.display {
  background: #131928;
  border-radius: var(--radius-md);
  padding: 20px;
  display: flex;
  flex-direction: column;
  gap: 8px;
  min-height: 96px;
  justify-content: flex-end;
}
.display-expr {
  color: #949eb0;
  font-size: 15px;
  text-align: right;
  min-height: 18px;
  word-break: break-all;
}
.display-result {
  color: #fff;
  font-size: 40px;
  font-weight: 500;
  text-align: right;
  word-break: break-all;
}

/* ===== Button grid ===== */
.button-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 16px;
  justify-content: center;
}
.grid-block {
  flex: 1 1 220px;
  min-width: 220px;
  max-width: 100%;
  display: flex;
  flex-direction: column;
  gap: 8px;
}
.grid-row {
  display: flex;
  gap: 8px;
}
.calc-btn {
  flex: 1;
  min-width: 0;
  aspect-ratio: 1 / 1;
  border-radius: 10px;
  border: none;
  font-size: 13px;
  font-weight: 500;
  background: #f3f5f8;
  color: #2e3340;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: filter 0.1s ease, transform 0.05s ease;
}
.calc-btn:hover { filter: brightness(0.96); }
.calc-btn:active { transform: scale(0.95); }

.calc-btn.num {
  background: #fff;
  border: 1px solid var(--border);
  color: #1c2128;
  font-size: 16px;
}
.calc-btn.op {
  background: var(--accent);
  color: #fff;
  font-size: 17px;
  font-weight: 600;
}
.calc-btn.ac {
  background: #fbeded;
  color: #dc2626;
  font-weight: 600;
}
.calc-btn.eq {
  background: var(--accent);
  color: #fff;
  font-size: 18px;
  font-weight: 700;
}

.deg-rad-toggle {
  position: relative;
  flex: 2;
  min-width: 0;
  display: flex;
  gap: 2px;
  padding: 3px;
  border-radius: 10px;
  background: #f3f5f8;
}
.toggle-thumb {
  position: absolute;
  top: 3px;
  left: 3px;
  width: calc(50% - 4px);
  height: calc(100% - 6px);
  background: var(--accent);
  border-radius: 8px;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  z-index: 0;
}
.deg-rad-toggle.rad-active .toggle-thumb {
  transform: translateX(calc(100% + 2px));
}
.deg-rad-toggle button {
  position: relative;
  z-index: 1;
  flex: 1;
  border: none;
  border-radius: 8px;
  background: transparent;
  font-size: 12px;
  font-weight: 600;
  color: #2e3340;
  transition: color 0.3s ease;
}
.deg-rad-toggle button.active {
  color: #fff;
}

/* ===== History panel ===== */
.history-panel {
  background: var(--card);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
  padding: 20px;
  width: 300px;
  max-width: 100%;
  flex: 0 1 300px;
  display: flex;
  flex-direction: column;
  gap: 16px;
}
.history-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
}
.history-header h2 {
  font-size: 16px;
  margin: 0;
  font-weight: 600;
}
.history-header button {
  border: none;
  background: none;
  color: var(--accent);
  font-size: 13px;
  font-weight: 500;
  padding: 0;
}
.history-list {
  display: flex;
  flex-direction: column;
  min-height: 120px;
}
.history-empty {
  color: var(--text-muted);
  font-size: 13px;
  text-align: center;
  padding: 24px 0;
}
.history-row {
  display: flex;
  flex-direction: column;
  align-items: flex-end;
  gap: 2px;
  padding: 10px 12px;
  border: none;
  background: transparent;
  border-bottom: 1px solid #eef0f3;
  text-align: right;
  width: 100%;
}
.history-row:hover { background: #f7f9fc; }
.history-row:first-child { background: #f3f5f9; border-radius: 8px; }
.history-row:last-child { border-bottom: none; }
.history-expr {
  font-size: 13px;
  color: var(--text-secondary);
}
.history-result {
  font-size: 15px;
  font-weight: 600;
  color: var(--text-primary);
}

@media (max-width: 1024px) {
  .calculator-layout { flex-direction: column; }
  .calculator-card { width: 100%; }
  .history-panel { width: 100%; flex-basis: auto; }
}

@media (max-width: 860px) {
  .calculator-card { padding: 18px; gap: 16px; width: 100%; }
  .calc-btn { font-size: 12px; }
  .calc-btn.num { font-size: 14px; }
  .grid-row { gap: 6px; }
  .grid-block { gap: 6px; }
  .button-grid { gap: 10px; }
  .history-panel { width: 100%; }
  .display-result { font-size: 30px; }
}