/* ============================================================
 *  Calculator · 高级计算器
 *  三种模式：标准 / 科学 / 程序员
 *  Apple 风格，玻璃质感
 * ============================================================ */

.calc-panel {
  position: relative;
  background: linear-gradient(160deg, rgba(20,20,26,0.95) 0%, rgba(10,10,14,0.98) 100%);
  border: 1px solid rgba(200,200,210,0.1);
  border-radius: 20px;
  backdrop-filter: blur(28px);
  box-shadow: 0 20px 60px rgba(0,0,0,0.5);
  overflow: hidden;
  animation: fadeInUp 0.9s cubic-bezier(0.23,1,0.32,1) 0.55s both;
  display: flex;
  flex-direction: column;
  height: 100%;
  min-height: 560px;
}
.calc-panel::before {
  content: '';
  position: absolute;
  top: 0; left: 0; right: 0;
  height: 1px;
  background: linear-gradient(90deg, transparent, rgba(201,168,118,0.5) 50%, transparent);
  opacity: 0.6;
}

.calc-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 12px 16px;
  border-bottom: 1px solid rgba(200,200,210,0.06);
}
.calc-title {
  font-size: 12px;
  color: var(--text-secondary);
  letter-spacing: 2px;
  text-transform: uppercase;
  display: flex;
  align-items: center;
  gap: 8px;
}
.calc-title-dot {
  width: 5px;
  height: 5px;
  background: var(--gold);
  border-radius: 50%;
  box-shadow: 0 0 6px var(--gold);
  animation: titlePulse 2s ease-in-out infinite;
}
.calc-mode-tabs {
  display: flex;
  gap: 4px;
  background: rgba(200,200,210,0.04);
  border-radius: 8px;
  padding: 2px;
}
.calc-mode-btn {
  font-size: 10px;
  padding: 4px 10px;
  background: transparent;
  border: none;
  border-radius: 6px;
  color: var(--text-muted);
  cursor: pointer;
  transition: all 0.3s;
  font-family: inherit;
  letter-spacing: 0.5px;
}
.calc-mode-btn:hover { color: var(--text-secondary); }
.calc-mode-btn.active {
  background: var(--gold);
  color: #1a1a1e;
  font-weight: 500;
}

.calc-display {
  padding: 18px 18px 14px;
  text-align: right;
  font-family: 'SF Mono', 'JetBrains Mono', Monaco, Consolas, monospace;
  min-height: 100px;
  display: flex;
  flex-direction: column;
  justify-content: flex-end;
  background: linear-gradient(180deg, rgba(0,0,0,0.2) 0%, transparent 100%);
}
.calc-history {
  font-size: 13px;
  color: var(--text-muted);
  min-height: 18px;
  margin-bottom: 6px;
  word-break: break-all;
  letter-spacing: 0.3px;
  overflow-x: auto;
  white-space: nowrap;
  -ms-overflow-style: none;
  scrollbar-width: none;
}
.calc-history::-webkit-scrollbar { display: none; }
.calc-current {
  font-size: 40px;
  font-weight: 200;
  color: var(--text-primary);
  letter-spacing: -1px;
  line-height: 1;
  font-variant-numeric: tabular-nums;
  word-break: break-all;
  min-height: 44px;
  text-shadow: 0 0 20px rgba(255,255,255,0.05);
  transition: color 0.3s, font-size 0.2s;
}
.calc-current.error {
  color: #ff453a;
  font-size: 22px;
  letter-spacing: 0;
}
.calc-current.solved {
  color: var(--gold);
  animation: calcSolved 0.5s cubic-bezier(0.34,1.56,0.64,1);
}
@keyframes calcSolved {
  0% { transform: scale(1); }
  50% { transform: scale(1.04); }
  100% { transform: scale(1); }
}

.calc-keys {
  display: grid;
  gap: 1px;
  padding: 1px;
  background: rgba(200,200,210,0.04);
  grid-template-columns: repeat(4, 1fr);
  flex: 1;
}
.calc-keys.sci {
  grid-template-columns: repeat(5, 1fr);
}
.calc-keys.prog {
  grid-template-columns: repeat(6, 1fr);
}

.calc-key {
  appearance: none;
  background: rgba(20,20,26,0.6);
  border: none;
  padding: 16px 8px;
  color: var(--text-primary);
  font-size: 17px;
  font-weight: 300;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.12s ease;
  position: relative;
  -webkit-tap-highlight-color: transparent;
  font-variant-numeric: tabular-nums;
  letter-spacing: -0.3px;
}
.calc-key:hover { background: rgba(40,40,50,0.7); }
.calc-key:active {
  background: rgba(201,168,118,0.18);
  transform: scale(0.96);
  color: var(--gold);
}
.calc-key.op {
  color: var(--gold);
  font-weight: 400;
  background: rgba(201,168,118,0.04);
}
.calc-key.op:hover { background: rgba(201,168,118,0.1); }
.calc-key.fn {
  color: var(--text-secondary);
  font-size: 14px;
  background: rgba(200,200,210,0.04);
}
.calc-key.fn:hover { background: rgba(200,200,210,0.08); }
.calc-key.eq {
  background: var(--gold);
  color: #1a1a1e;
  font-weight: 500;
  font-size: 22px;
}
.calc-key.eq:hover { background: #d4b888; }
.calc-key.clear {
  color: #ff453a;
  background: rgba(255,69,58,0.08);
}
.calc-key.clear:hover { background: rgba(255,69,58,0.15); }
.calc-key.sci-only, .calc-key.prog-only { display: none; }
.calc-keys.sci .calc-key.sci-only { display: block; }
.calc-keys.prog .calc-key.prog-only { display: block; }
.calc-keys.prog .calc-key.sci-only { display: none; }

.calc-foot {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 8px 16px;
  border-top: 1px solid rgba(200,200,210,0.06);
  font-size: 10px;
  color: var(--text-muted);
  letter-spacing: 0.5px;
  font-family: 'SF Mono', Monaco, monospace;
}
.calc-foot-hint {
  display: flex;
  gap: 10px;
}
.calc-foot-hint kbd {
  display: inline-block;
  padding: 1px 5px;
  background: rgba(200,200,210,0.06);
  border: 1px solid rgba(200,200,210,0.12);
  border-radius: 3px;
  font-family: inherit;
  font-size: 9px;
  color: var(--text-secondary);
  margin: 0 1px;
}
.calc-foot-clear {
  cursor: pointer;
  transition: color 0.3s;
  padding: 2px 6px;
  border-radius: 4px;
}
.calc-foot-clear:hover { color: var(--gold); background: rgba(201,168,118,0.08); }

.calc-history-panel {
  position: absolute;
  inset: 0;
  background: rgba(10,10,14,0.98);
  backdrop-filter: blur(20px);
  padding: 16px;
  display: none;
  flex-direction: column;
  z-index: 10;
  border-radius: inherit;
}
.calc-history-panel.show { display: flex; }
.calc-history-head {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 12px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(200,200,210,0.06);
}
.calc-history-title {
  font-size: 12px;
  color: var(--text-secondary);
  letter-spacing: 1.5px;
  text-transform: uppercase;
}
.calc-history-close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  font-size: 20px;
  width: 28px;
  height: 28px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s;
}
.calc-history-close:hover { background: rgba(200,200,210,0.08); color: var(--text-primary); }
.calc-history-list {
  flex: 1;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 1px;
}
.calc-history-item {
  padding: 10px 8px;
  background: rgba(200,200,210,0.02);
  border-radius: 8px;
  cursor: pointer;
  transition: background 0.2s;
}
.calc-history-item:hover { background: rgba(201,168,118,0.05); }
.calc-history-expr {
  font-size: 11px;
  color: var(--text-muted);
  font-family: 'SF Mono', monospace;
}
.calc-history-result {
  font-size: 17px;
  color: var(--text-primary);
  font-weight: 300;
  text-align: right;
  font-family: 'SF Mono', monospace;
  margin-top: 2px;
}
.calc-history-empty {
  text-align: center;
  padding: 30px 10px;
  color: var(--text-muted);
  font-size: 12px;
  font-style: italic;
}

@media (max-width: 768px) {
  .calc-key { padding: 14px 4px; font-size: 15px; }
  .calc-current { font-size: 32px; }
  .calc-keys.sci { grid-template-columns: repeat(5, 1fr); }
  .calc-keys.prog { grid-template-columns: repeat(5, 1fr); }
}