/* ==========================================================================
   NEO-CALC PRO - Advanced Glassmorphic Calculator Design System
   ========================================================================== */

/* Theme Variables & Tokens */
:root, [data-theme="cyber-dark"] {
  --bg-gradient: radial-gradient(circle at 20% 20%, #0f172a 0%, #020617 100%);
  --orb-1: #00f2fe;
  --orb-2: #4facfe;
  --orb-3: #7000ff;
  
  --card-bg: rgba(15, 23, 42, 0.72);
  --card-border: rgba(255, 255, 255, 0.12);
  --card-shadow: 0 25px 60px -15px rgba(0, 0, 0, 0.7), 0 0 40px rgba(0, 242, 254, 0.12);
  
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  
  --display-bg: rgba(2, 6, 23, 0.65);
  --display-border: rgba(255, 255, 255, 0.08);
  
  --btn-num-bg: rgba(30, 41, 59, 0.6);
  --btn-num-hover: rgba(51, 65, 85, 0.8);
  --btn-num-active: rgba(71, 85, 105, 0.9);
  --btn-num-color: #f1f5f9;
  
  --btn-fn-bg: rgba(51, 65, 85, 0.5);
  --btn-fn-hover: rgba(71, 85, 105, 0.7);
  --btn-fn-color: #38bdf8;
  
  --btn-op-bg: rgba(14, 165, 233, 0.2);
  --btn-op-hover: rgba(14, 165, 233, 0.35);
  --btn-op-color: #38bdf8;
  --btn-op-border: rgba(56, 189, 248, 0.3);
  
  --btn-equals-bg: linear-gradient(135deg, #00f2fe 0%, #4facfe 100%);
  --btn-equals-color: #020617;
  --btn-equals-shadow: 0 8px 25px rgba(0, 242, 254, 0.45);
  
  --accent-glow: #00f2fe;
  --accent-color: #38bdf8;
  --danger-color: #f43f5e;
}

[data-theme="aurora-glass"] {
  --bg-gradient: radial-gradient(circle at 10% 20%, #1e1035 0%, #0b0217 100%);
  --orb-1: #ff007f;
  --orb-2: #7928ca;
  --orb-3: #00dfd8;
  
  --card-bg: rgba(30, 16, 53, 0.68);
  --card-border: rgba(255, 255, 255, 0.15);
  --card-shadow: 0 25px 60px -15px rgba(0, 0, 0, 0.8), 0 0 45px rgba(255, 0, 127, 0.18);
  
  --text-primary: #ffffff;
  --text-secondary: #d8b4fe;
  --text-muted: #9333ea;
  
  --display-bg: rgba(15, 5, 29, 0.7);
  --display-border: rgba(255, 255, 255, 0.1);
  
  --btn-num-bg: rgba(59, 25, 91, 0.55);
  --btn-num-hover: rgba(88, 28, 135, 0.75);
  --btn-num-active: rgba(107, 33, 168, 0.9);
  --btn-num-color: #faf5ff;
  
  --btn-fn-bg: rgba(76, 29, 149, 0.45);
  --btn-fn-hover: rgba(109, 40, 217, 0.65);
  --btn-fn-color: #f472b6;
  
  --btn-op-bg: rgba(236, 72, 153, 0.2);
  --btn-op-hover: rgba(236, 72, 153, 0.35);
  --btn-op-color: #f472b6;
  --btn-op-border: rgba(244, 114, 182, 0.35);
  
  --btn-equals-bg: linear-gradient(135deg, #ff007f 0%, #7928ca 100%);
  --btn-equals-color: #ffffff;
  --btn-equals-shadow: 0 8px 25px rgba(255, 0, 127, 0.5);
  
  --accent-glow: #ff007f;
  --accent-color: #f472b6;
  --danger-color: #fb7185;
}

[data-theme="midnight-oled"] {
  --bg-gradient: #000000;
  --orb-1: #ff6b00;
  --orb-2: #ff9900;
  --orb-3: #333333;
  
  --card-bg: rgba(18, 18, 18, 0.9);
  --card-border: rgba(255, 255, 255, 0.1);
  --card-shadow: 0 25px 60px -15px rgba(0, 0, 0, 1), 0 0 35px rgba(255, 153, 0, 0.1);
  
  --text-primary: #ffffff;
  --text-secondary: #a1a1aa;
  --text-muted: #71717a;
  
  --display-bg: rgba(0, 0, 0, 0.95);
  --display-border: rgba(255, 255, 255, 0.07);
  
  --btn-num-bg: rgba(39, 39, 42, 0.7);
  --btn-num-hover: rgba(63, 63, 70, 0.85);
  --btn-num-active: rgba(82, 82, 91, 1);
  --btn-num-color: #f4f4f5;
  
  --btn-fn-bg: rgba(63, 63, 70, 0.6);
  --btn-fn-hover: rgba(82, 82, 91, 0.8);
  --btn-fn-color: #fbbf24;
  
  --btn-op-bg: rgba(245, 158, 11, 0.2);
  --btn-op-hover: rgba(245, 158, 11, 0.35);
  --btn-op-color: #fbbf24;
  --btn-op-border: rgba(245, 158, 11, 0.3);
  
  --btn-equals-bg: linear-gradient(135deg, #ff9900 0%, #ff5500 100%);
  --btn-equals-color: #000000;
  --btn-equals-shadow: 0 8px 25px rgba(255, 153, 0, 0.4);
  
  --accent-glow: #ff9900;
  --accent-color: #fbbf24;
  --danger-color: #ef4444;
}

[data-theme="platinum-light"] {
  --bg-gradient: radial-gradient(circle at 10% 20%, #e2e8f0 0%, #cbd5e1 100%);
  --orb-1: #60a5fa;
  --orb-2: #c084fc;
  --orb-3: #38bdf8;
  
  --card-bg: rgba(255, 255, 255, 0.75);
  --card-border: rgba(255, 255, 255, 0.8);
  --card-shadow: 0 25px 60px -15px rgba(71, 85, 105, 0.25), 0 0 35px rgba(59, 130, 246, 0.15);
  
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  
  --display-bg: rgba(248, 250, 252, 0.85);
  --display-border: rgba(203, 213, 225, 0.8);
  
  --btn-num-bg: rgba(255, 255, 255, 0.85);
  --btn-num-hover: rgba(241, 245, 249, 1);
  --btn-num-active: rgba(226, 232, 240, 1);
  --btn-num-color: #0f172a;
  
  --btn-fn-bg: rgba(226, 232, 240, 0.85);
  --btn-fn-hover: rgba(203, 213, 225, 1);
  --btn-fn-color: #0284c7;
  
  --btn-op-bg: rgba(224, 242, 254, 0.9);
  --btn-op-hover: rgba(186, 230, 253, 1);
  --btn-op-color: #0284c7;
  --btn-op-border: rgba(56, 189, 248, 0.4);
  
  --btn-equals-bg: linear-gradient(135deg, #2563eb 0%, #3b82f6 100%);
  --btn-equals-color: #ffffff;
  --btn-equals-shadow: 0 8px 25px rgba(37, 99, 235, 0.35);
  
  --accent-glow: #3b82f6;
  --accent-color: #2563eb;
  --danger-color: #e11d48;
}

/* Base Resets */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
  -webkit-tap-highlight-color: transparent;
}

body {
  font-family: 'Outfit', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  background: var(--bg-gradient);
  min-height: 100vh;
  color: var(--text-primary);
  display: flex;
  justify-content: center;
  align-items: center;
  padding: 1.5rem 1rem;
  overflow-x: hidden;
  position: relative;
  transition: background 0.4s ease, color 0.4s ease;
}

/* Dynamic Animated Background */
.bg-scene {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: hidden;
}

.glow-orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(90px);
  opacity: 0.4;
  animation: floatOrb 18s ease-in-out infinite alternate;
}

.orb-1 {
  width: 400px;
  height: 400px;
  background: var(--orb-1);
  top: -100px;
  left: -80px;
}

.orb-2 {
  width: 480px;
  height: 480px;
  background: var(--orb-2);
  bottom: -150px;
  right: -100px;
  animation-duration: 22s;
  animation-delay: -5s;
}

.orb-3 {
  width: 320px;
  height: 320px;
  background: var(--orb-3);
  top: 40%;
  left: 60%;
  animation-duration: 16s;
  animation-delay: -10s;
}

@keyframes floatOrb {
  0% { transform: translate(0, 0) scale(1); }
  50% { transform: translate(60px, 40px) scale(1.1); }
  100% { transform: translate(-40px, 80px) scale(0.95); }
}

.noise-overlay {
  position: absolute;
  inset: 0;
  background-image: radial-gradient(rgba(255, 255, 255, 0.03) 1px, transparent 0);
  background-size: 24px 24px;
}

/* App Container */
.calculator-app {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 880px;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Header */
.app-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.75rem 1.25rem;
  background: var(--card-bg);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  box-shadow: var(--card-shadow);
}

.brand {
  display: flex;
  align-items: center;
  gap: 0.85rem;
}

.logo-icon {
  width: 44px;
  height: 44px;
  border-radius: 12px;
  background: var(--btn-equals-bg);
  color: var(--btn-equals-color);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.25rem;
  box-shadow: 0 4px 15px rgba(0, 242, 254, 0.35);
}

.brand-text h1 {
  font-size: 1.2rem;
  font-weight: 700;
  letter-spacing: -0.5px;
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.brand-text .badge {
  font-size: 0.65rem;
  font-weight: 800;
  padding: 2px 6px;
  background: var(--accent-glow);
  color: #000;
  border-radius: 6px;
  letter-spacing: 0.5px;
}

.brand-text p {
  font-size: 0.75rem;
  color: var(--text-secondary);
}

.header-controls {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  position: relative;
}

.icon-btn {
  width: 38px;
  height: 38px;
  border-radius: 10px;
  border: 1px solid var(--card-border);
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.95rem;
  cursor: pointer;
  transition: all 0.2s ease;
}

.icon-btn:hover {
  background: rgba(255, 255, 255, 0.15);
  transform: translateY(-1px);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.icon-btn.active {
  background: var(--btn-op-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

/* Theme Selector Dropdown */
.theme-selector-wrapper {
  position: relative;
}

.theme-menu {
  position: absolute;
  top: calc(100% + 10px);
  right: 0;
  background: var(--card-bg);
  backdrop-filter: blur(25px);
  -webkit-backdrop-filter: blur(25px);
  border: 1px solid var(--card-border);
  border-radius: 14px;
  padding: 0.5rem;
  display: none;
  flex-direction: column;
  gap: 0.35rem;
  min-width: 170px;
  box-shadow: 0 15px 35px rgba(0, 0, 0, 0.5);
  z-index: 100;
  animation: fadeInDown 0.2s ease forwards;
}

.theme-menu.show {
  display: flex;
}

.theme-opt {
  display: flex;
  align-items: center;
  gap: 0.65rem;
  padding: 0.55rem 0.75rem;
  background: transparent;
  border: none;
  border-radius: 8px;
  color: var(--text-primary);
  font-size: 0.82rem;
  font-weight: 500;
  font-family: inherit;
  cursor: pointer;
  transition: background 0.15s ease;
  text-align: left;
}

.theme-opt:hover {
  background: rgba(255, 255, 255, 0.1);
}

.theme-opt.active {
  background: var(--btn-op-bg);
  color: var(--accent-color);
}

.theme-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  display: inline-block;
  box-shadow: 0 0 8px currentColor;
}

/* Main Layout Grid */
.calc-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  transition: all 0.3s ease;
}

.calc-container.with-history {
  grid-template-columns: 1fr 290px;
}

/* Main Card */
.calc-main-card {
  background: var(--card-bg);
  backdrop-filter: blur(25px);
  -webkit-backdrop-filter: blur(25px);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 1.5rem;
  box-shadow: var(--card-shadow);
  display: flex;
  flex-direction: column;
  gap: 1.1rem;
}

/* Mode Switcher Tabs */
.mode-tabs {
  display: flex;
  background: rgba(0, 0, 0, 0.2);
  border: 1px solid var(--card-border);
  padding: 0.3rem;
  border-radius: 14px;
  gap: 0.3rem;
}

.mode-tab {
  flex: 1;
  padding: 0.55rem 0.75rem;
  background: transparent;
  border: none;
  border-radius: 10px;
  color: var(--text-secondary);
  font-size: 0.85rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.5rem;
  transition: all 0.2s ease;
}

.mode-tab:hover {
  color: var(--text-primary);
}

.mode-tab.active {
  background: var(--display-bg);
  color: var(--accent-color);
  box-shadow: 0 2px 8px rgba(0, 0, 0, 0.2);
  border: 1px solid var(--card-border);
}

/* Display Screen */
.display-screen {
  background: var(--display-bg);
  border: 1px solid var(--display-border);
  border-radius: 18px;
  padding: 1rem 1.25rem;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  min-height: 140px;
  box-shadow: inset 0 2px 8px rgba(0, 0, 0, 0.4);
  position: relative;
  overflow: hidden;
}

.display-status-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.75rem;
  color: var(--text-muted);
}

.angle-mode-badge, .memory-badge {
  font-family: 'Fira Code', monospace;
  font-size: 0.7rem;
  font-weight: 600;
  padding: 2px 6px;
  border-radius: 4px;
  background: rgba(255, 255, 255, 0.08);
  color: var(--accent-color);
}

.copy-display-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 4px 6px;
  border-radius: 6px;
  font-size: 0.85rem;
  transition: all 0.15s ease;
}

.copy-display-btn:hover {
  color: var(--accent-color);
  background: rgba(255, 255, 255, 0.08);
}

.expression-line {
  font-family: 'Fira Code', monospace;
  color: var(--text-secondary);
  font-size: 0.95rem;
  min-height: 1.4rem;
  text-align: right;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
}
.expression-line::-webkit-scrollbar { display: none; }

.output-line {
  font-family: 'Fira Code', monospace;
  font-size: 2.5rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: right;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
  line-height: 1.1;
  letter-spacing: -1px;
  transition: font-size 0.15s ease;
}
.output-line::-webkit-scrollbar { display: none; }

.preview-line {
  font-family: 'Fira Code', monospace;
  color: var(--accent-color);
  font-size: 0.85rem;
  min-height: 1.1rem;
  text-align: right;
  opacity: 0.85;
}

/* Memory Bar */
.memory-bar {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.4rem;
}

.mem-btn {
  padding: 0.4rem;
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--card-border);
  border-radius: 8px;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all 0.15s ease;
}

.mem-btn:hover {
  background: rgba(255, 255, 255, 0.1);
  color: var(--accent-color);
}

/* Keypad Styles */
.standard-keypad {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.65rem;
}

.scientific-keypad {
  display: none;
  grid-template-columns: repeat(5, 1fr);
  gap: 0.5rem;
  padding-bottom: 0.5rem;
  border-bottom: 1px solid var(--card-border);
  animation: fadeIn 0.25s ease forwards;
}

.scientific-keypad.show {
  display: grid;
}

/* Buttons (Keys) */
.key {
  position: relative;
  display: flex;
  align-items: center;
  justify-content: center;
  height: 54px;
  border-radius: 14px;
  border: 1px solid var(--card-border);
  font-family: 'Fira Code', 'Outfit', sans-serif;
  font-size: 1.15rem;
  font-weight: 500;
  cursor: pointer;
  user-select: none;
  transition: transform 0.08s ease, background 0.15s ease, box-shadow 0.15s ease;
  overflow: hidden;
}

.key:active, .key.pressed {
  transform: scale(0.94);
}

.num-key {
  background: var(--btn-num-bg);
  color: var(--btn-num-color);
}
.num-key:hover {
  background: var(--btn-num-hover);
}

.fn-key {
  background: var(--btn-fn-bg);
  color: var(--btn-fn-color);
  font-weight: 600;
}
.fn-key:hover {
  background: var(--btn-fn-hover);
}
.clear-key {
  color: var(--danger-color);
}

.op-key {
  background: var(--btn-op-bg);
  color: var(--btn-op-color);
  border-color: var(--btn-op-border);
  font-size: 1.35rem;
  font-weight: 600;
}
.op-key:hover {
  background: var(--btn-op-hover);
  box-shadow: 0 0 12px var(--btn-op-border);
}

.equals-key {
  background: var(--btn-equals-bg);
  color: var(--btn-equals-color);
  font-size: 1.45rem;
  font-weight: 700;
  border: none;
  box-shadow: var(--btn-equals-shadow);
}
.equals-key:hover {
  filter: brightness(1.1);
  box-shadow: 0 10px 30px rgba(0, 242, 254, 0.6);
}

.sc-key {
  height: 44px;
  font-size: 0.85rem;
  background: rgba(255, 255, 255, 0.04);
  color: var(--text-secondary);
  border-radius: 10px;
}
.sc-key:hover {
  background: rgba(255, 255, 255, 0.12);
  color: var(--accent-color);
  border-color: var(--accent-color);
}

/* Converter Panel */
.converter-panel {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  animation: fadeIn 0.25s ease forwards;
}

.converter-category-tabs {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 0.4rem;
}

.conv-tab {
  padding: 0.5rem 0.25rem;
  background: rgba(255, 255, 255, 0.04);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  color: var(--text-secondary);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 0.35rem;
  transition: all 0.2s ease;
}

.conv-tab.active {
  background: var(--btn-op-bg);
  border-color: var(--accent-color);
  color: var(--accent-color);
}

.converter-box {
  background: var(--display-bg);
  border: 1px solid var(--display-border);
  border-radius: 16px;
  padding: 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
}

.conv-row {
  display: flex;
  flex-direction: column;
  gap: 0.4rem;
}

.conv-row label {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.conv-input-group {
  display: grid;
  grid-template-columns: 1fr 130px;
  gap: 0.5rem;
}

.conv-input-group input {
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 0.65rem 0.85rem;
  font-family: 'Fira Code', monospace;
  font-size: 1.1rem;
  color: var(--text-primary);
  outline: none;
}
.conv-input-group input:focus {
  border-color: var(--accent-color);
}

.conv-input-group select {
  background: rgba(255, 255, 255, 0.08);
  border: 1px solid var(--card-border);
  border-radius: 10px;
  padding: 0.65rem;
  font-family: inherit;
  font-size: 0.85rem;
  color: var(--text-primary);
  outline: none;
  cursor: pointer;
}
.conv-input-group select option {
  background: #0f172a;
  color: #fff;
}

.conv-divider {
  display: flex;
  justify-content: center;
  margin: -0.25rem 0;
}

.conv-swap-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  background: var(--btn-op-bg);
  border: 1px solid var(--accent-color);
  color: var(--accent-color);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: transform 0.2s ease;
}
.conv-swap-btn:hover {
  transform: rotate(180deg) scale(1.1);
}

.conv-formula-display {
  font-size: 0.8rem;
  color: var(--text-secondary);
  text-align: center;
  margin-top: 0.25rem;
}

/* History Drawer */
.calc-history-drawer {
  background: var(--card-bg);
  backdrop-filter: blur(25px);
  -webkit-backdrop-filter: blur(25px);
  border: 1px solid var(--card-border);
  border-radius: 24px;
  padding: 1.25rem;
  box-shadow: var(--card-shadow);
  display: none;
  flex-direction: column;
  gap: 0.85rem;
  max-height: 560px;
}

.calc-container.with-history .calc-history-drawer {
  display: flex;
  animation: fadeInRight 0.25s ease forwards;
}

.history-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-bottom: 0.65rem;
  border-bottom: 1px solid var(--card-border);
}

.history-header h3 {
  font-size: 0.95rem;
  font-weight: 600;
  display: flex;
  align-items: center;
  gap: 0.45rem;
}

.clear-history-btn {
  background: transparent;
  border: none;
  color: var(--danger-color);
  font-size: 0.75rem;
  font-weight: 600;
  cursor: pointer;
  display: flex;
  align-items: center;
  gap: 0.3rem;
  padding: 4px 6px;
  border-radius: 6px;
}
.clear-history-btn:hover {
  background: rgba(244, 63, 94, 0.1);
}

.history-list {
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  overflow-y: auto;
  padding-right: 0.25rem;
  scrollbar-width: thin;
}

.history-item {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--card-border);
  border-radius: 12px;
  padding: 0.65rem 0.85rem;
  cursor: pointer;
  transition: all 0.15s ease;
}

.history-item:hover {
  background: rgba(255, 255, 255, 0.08);
  border-color: var(--accent-color);
  transform: translateX(2px);
}

.hist-exp {
  font-family: 'Fira Code', monospace;
  font-size: 0.8rem;
  color: var(--text-muted);
  text-align: right;
}

.hist-res {
  font-family: 'Fira Code', monospace;
  font-size: 1.1rem;
  font-weight: 600;
  color: var(--text-primary);
  text-align: right;
  margin-top: 0.15rem;
}

.empty-history {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 2.5rem 1rem;
  text-align: center;
  color: var(--text-muted);
  gap: 0.4rem;
}
.empty-history i {
  font-size: 2rem;
  margin-bottom: 0.5rem;
  opacity: 0.5;
}
.empty-history p {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
}
.empty-history span {
  font-size: 0.75rem;
}

/* Footer */
.app-footer {
  text-align: center;
  font-size: 0.78rem;
  color: var(--text-secondary);
  padding: 0.5rem;
}

/* Modal Dialog */
.modal-dialog {
  border: none;
  background: transparent;
  padding: 1rem;
  max-width: 520px;
  width: 90%;
  margin: auto;
}

.modal-dialog::backdrop {
  background: rgba(0, 0, 0, 0.75);
  backdrop-filter: blur(8px);
}

.modal-content {
  background: var(--card-bg);
  backdrop-filter: blur(30px);
  -webkit-backdrop-filter: blur(30px);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  padding: 1.5rem;
  color: var(--text-primary);
  box-shadow: var(--card-shadow);
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  padding-bottom: 0.75rem;
  border-bottom: 1px solid var(--card-border);
}

.modal-header h2 {
  font-size: 1.15rem;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.close-modal-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  font-size: 1.5rem;
  cursor: pointer;
}
.close-modal-btn:hover {
  color: var(--text-primary);
}

.shortcut-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 0.65rem;
}

.shortcut-item {
  display: flex;
  align-items: center;
  gap: 0.5rem;
  font-size: 0.82rem;
  color: var(--text-secondary);
}

kbd {
  background: rgba(255, 255, 255, 0.1);
  border: 1px solid var(--card-border);
  border-radius: 6px;
  padding: 2px 6px;
  font-family: 'Fira Code', monospace;
  font-size: 0.78rem;
  color: var(--accent-color);
}

/* Toast */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: rgba(15, 23, 42, 0.95);
  color: #38bdf8;
  border: 1px solid rgba(56, 189, 248, 0.3);
  padding: 0.75rem 1.5rem;
  border-radius: 30px;
  font-size: 0.85rem;
  font-weight: 500;
  backdrop-filter: blur(15px);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.5);
  opacity: 0;
  pointer-events: none;
  transition: transform 0.3s cubic-bezier(0.175, 0.885, 0.32, 1.275), opacity 0.3s ease;
  z-index: 1000;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(-5px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInDown {
  from { opacity: 0; transform: translateY(-10px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInRight {
  from { opacity: 0; transform: translateX(15px); }
  to { opacity: 1; transform: translateX(0); }
}

/* Media Queries */
@media (max-width: 768px) {
  .calc-container.with-history {
    grid-template-columns: 1fr;
  }
  
  .calc-main-card {
    padding: 1.1rem;
  }
  
  .output-line {
    font-size: 2rem;
  }
  
  .key {
    height: 48px;
    font-size: 1.05rem;
  }
  
  .shortcut-grid {
    grid-template-columns: 1fr;
  }
}