/* ==========================================================================
   Design System & Variable Declarations
   ========================================================================== */
:root {
  /* Color Palette (Sleek Dark Mode / Vibrant Gradients) */
  --bg-main: #0a0b10;
  --bg-gradient: radial-gradient(circle at 50% 0%, #151828 0%, #06070a 100%);
  
  --card-bg: rgba(20, 22, 37, 0.7);
  --card-border: rgba(255, 255, 255, 0.06);
  --card-glow: rgba(0, 0, 0, 0.3);
  
  --primary-color: #6366f1; /* Indigo */
  --secondary-color: #c084fc; /* Violet */
  --accent-color: #f43f5e; /* Rose */
  
  --primary-gradient: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #d946ef 100%);
  --btn-hover-gradient: linear-gradient(135deg, #4f46e5 0%, #7c3aed 50%, #c084fc 100%);
  
  --glow-color: rgba(99, 102, 241, 0.5);
  --glow-color-rose: rgba(244, 63, 94, 0.3);
  
  /* Text Colors */
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #475569;
  
  /* Inputs & Interactive elements */
  --input-bg: rgba(13, 15, 28, 0.8);
  --input-border: rgba(255, 255, 255, 0.1);
  --input-focus-border: #6366f1;
  --input-focus-glow: rgba(99, 102, 241, 0.25);
  
  /* Fonts */
  --font-heading: 'Outfit', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  
  /* Transitions */
  --transition-smooth: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  --transition-fast: all 0.15s ease;
}

/* ==========================================================================
   Reset & Base Styles
   ========================================================================== */
*, *::before, *::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

body {
  font-family: var(--font-body);
  background-color: var(--bg-main);
  background-image: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  padding: 20px;
}

/* Scrollbar Styles */
::-webkit-scrollbar {
  width: 8px;
}
::-webkit-scrollbar-track {
  background: rgba(0, 0, 0, 0.2);
}
::-webkit-scrollbar-thumb {
  background: rgba(255, 255, 255, 0.1);
  border-radius: 4px;
}
::-webkit-scrollbar-thumb:hover {
  background: rgba(255, 255, 255, 0.2);
}

/* Keyboard Navigation Outline */
*:focus-visible {
  outline: 2px solid var(--secondary-color);
  outline-offset: 3px;
}

/* ==========================================================================
   App Layout & Container
   ========================================================================== */
.app-container {
  width: 100%;
  max-width: 900px;
  display: flex;
  flex-direction: column;
  gap: 30px;
}

.app-header {
  text-align: center;
}

.logo-area {
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 12px;
  margin-bottom: 6px;
}

.logo-icon {
  width: 36px;
  height: 36px;
  color: var(--primary-color);
  filter: drop-shadow(0 0 8px var(--glow-color));
  animation: float 4s ease-in-out infinite;
}

.app-header h1 {
  font-family: var(--font-heading);
  font-size: 2.2rem;
  font-weight: 800;
  letter-spacing: -0.5px;
  background: var(--primary-gradient);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
  font-weight: 400;
  letter-spacing: 0.5px;
}

/* ==========================================================================
   Main Grid Layout
   ========================================================================== */
.app-main {
  display: grid;
  grid-template-columns: 1fr;
  gap: 24px;
}

@media (min-width: 768px) {
  .app-main {
    grid-template-columns: 1.1fr 0.9fr;
  }
}

/* ==========================================================================
   Glassmorphism Cards
   ========================================================================== */
.result-card, .settings-section {
  background: var(--card-bg);
  border: 1px solid var(--card-border);
  border-radius: 20px;
  box-shadow: 0 20px 40px var(--card-glow);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  padding: 24px;
  display: flex;
  flex-direction: column;
  transition: var(--transition-smooth);
}

.result-card:hover, .settings-section:hover {
  border-color: rgba(255, 255, 255, 0.1);
  box-shadow: 0 24px 48px rgba(0, 0, 0, 0.4), 0 0 20px rgba(99, 102, 241, 0.05);
}

/* ==========================================================================
   Result Section
   ========================================================================== */
.result-card {
  height: 100%;
  min-height: 380px;
}

.result-card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 20px;
}

.result-actions {
  display: flex;
  align-items: center;
  gap: 8px;
}

.result-badge {
  font-family: var(--font-heading);
  font-size: 0.75rem;
  font-weight: 800;
  letter-spacing: 1.5px;
  color: var(--text-primary);
  background: var(--primary-gradient);
  padding: 4px 12px;
  border-radius: 99px;
  box-shadow: 0 0 10px rgba(99, 102, 241, 0.3);
}

.result-display-wrapper {
  flex-grow: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  background: linear-gradient(180deg, rgba(0, 0, 0, 0.25) 0%, rgba(0, 0, 0, 0.1) 100%);
  border-radius: 12px;
  border: 1px dashed rgba(255, 255, 255, 0.05);
  padding: 20px 16px;
  max-height: 480px;
  overflow-y: auto;
}

.result-display {
  width: 100%;
  display: flex;
  flex-direction: column;
  align-items: flex-start;
  justify-content: flex-start;
}

.result-display.placeholder {
  color: var(--text-muted);
  font-size: 0.95rem;
  font-style: italic;
  max-width: 220px;
  text-align: center;
  align-self: center;
  margin: auto 0;
}

/* Results Grid Layout */
.results-grid-container {
  width: 100%;
  display: flex;
  flex-wrap: wrap;
  justify-content: flex-start;
  gap: 10px;
  padding: 10px 0;
}

.result-grid-item {
  font-family: var(--font-heading);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  background: linear-gradient(135deg, rgba(255, 255, 255, 0.04) 0%, rgba(255, 255, 255, 0.01) 100%);
  border: 1px solid rgba(255, 255, 255, 0.06);
  border-radius: 12px;
  width: 48px;
  height: 48px;
  display: flex;
  justify-content: center;
  align-items: center;
  box-shadow: 0 4px 12px rgba(0, 0, 0, 0.2);
  animation: numberPop 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
  transition: var(--transition-fast);
  cursor: pointer;
  user-select: none;
}

.result-grid-item:hover {
  background: var(--primary-gradient);
  border-color: transparent;
  box-shadow: 0 0 12px var(--glow-color);
  transform: translateY(-2px);
  color: #ffffff;
}

.result-grid-item.copied {
  background: linear-gradient(135deg, #10b981 0%, #059669 100%) !important;
  border-color: transparent !important;
  box-shadow: 0 0 15px rgba(16, 185, 129, 0.6) !important;
  color: #ffffff !important;
  transform: scale(0.95);
}

.icon-btn.success {
  color: #10b981 !important;
}

/* ==========================================================================
   Form & Controls
   ========================================================================== */
.form-group-row {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
  margin-bottom: 20px;
}

.form-group {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-bottom: 20px;
}

.form-group label {
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 0.5px;
}

/* Number input with + / - buttons */
.number-input-container {
  display: flex;
  align-items: center;
  background: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 12px;
  overflow: hidden;
  height: 48px;
  transition: var(--transition-fast);
}

.number-input-container:focus-within {
  border-color: var(--input-focus-border);
  box-shadow: 0 0 0 3px var(--input-focus-glow);
}

.number-input-container input[type="number"] {
  flex-grow: 1;
  width: 50px;
  height: 100%;
  border: none;
  background: transparent;
  color: var(--text-primary);
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 600;
  text-align: center;
  outline: none;
  -appearance: textfield;
  -moz-appearance: textfield;
}

.number-input-container input[type="number"]::-webkit-outer-spin-button,
.number-input-container input[type="number"]::-webkit-inner-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

.step-btn {
  width: 48px;
  height: 48px;
  background: transparent;
  border: none;
  color: var(--text-secondary);
  font-size: 1.4rem;
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  user-select: none;
  transition: var(--transition-fast);
}

.step-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--text-primary);
}

.step-btn:active {
  background: rgba(255, 255, 255, 0.1);
  transform: scale(0.95);
}

/* Range Sliders */
.slider-group {
  margin-top: -10px;
  margin-bottom: 24px;
}

.slider-label-row {
  display: flex;
  justify-content: space-between;
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 600;
  margin-bottom: 6px;
}

.slider-current-label {
  color: var(--text-secondary);
  font-weight: 700;
}

input[type="range"] {
  -webkit-appearance: none;
  width: 100%;
  height: 6px;
  background: rgba(255, 255, 255, 0.08);
  border-radius: 3px;
  outline: none;
  transition: var(--transition-fast);
}

/* Custom thumb styling */
input[type="range"]::-webkit-slider-thumb {
  -webkit-appearance: none;
  width: 18px;
  height: 18px;
  border-radius: 50%;
  background: var(--primary-color);
  box-shadow: 0 0 8px var(--glow-color);
  cursor: pointer;
  transition: var(--transition-fast);
}

input[type="range"]::-webkit-slider-thumb:hover {
  transform: scale(1.25);
  background: var(--secondary-color);
}

input[type="range"]::-webkit-slider-thumb:active {
  background: var(--secondary-color);
  box-shadow: 0 0 12px var(--glow-color);
}

input[type="range"]::-moz-range-thumb {
  width: 18px;
  height: 18px;
  border: none;
  border-radius: 50%;
  background: var(--primary-color);
  box-shadow: 0 0 8px var(--glow-color);
  cursor: pointer;
  transition: var(--transition-fast);
}

input[type="range"]::-moz-range-thumb:hover {
  transform: scale(1.25);
  background: var(--secondary-color);
}

input[type="range"]::-moz-range-thumb:active {
  background: var(--secondary-color);
  box-shadow: 0 0 12px var(--glow-color);
}

/* Quick Select Buttons */
.quick-group {
  margin-bottom: 24px;
}

.quick-title {
  font-size: 0.75rem;
  font-weight: 700;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 8px;
}

.quick-buttons {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  align-items: center;
}

.no-history-text {
  font-size: 0.8rem;
  color: var(--text-muted);
  font-style: italic;
  padding: 4px 0;
  user-select: none;
}

.quick-btn, .quick-count-btn {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid rgba(255, 255, 255, 0.05);
  color: var(--text-secondary);
  font-size: 0.8rem;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 8px;
  cursor: pointer;
  transition: var(--transition-fast);
}

.quick-btn:hover, .quick-count-btn:hover {
  background: rgba(99, 102, 241, 0.1);
  border-color: rgba(99, 102, 241, 0.3);
  color: var(--text-primary);
  transform: translateY(-1px);
}

.quick-btn:active, .quick-count-btn:active {
  transform: translateY(0);
}

/* Custom Checkbox */
.checkbox-group {
  margin-bottom: 28px;
}

.custom-checkbox {
  display: flex;
  align-items: center;
  position: relative;
  padding-left: 32px;
  cursor: pointer;
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-secondary);
  user-select: none;
}

.custom-checkbox input {
  position: absolute;
  opacity: 0;
  cursor: pointer;
  height: 0;
  width: 0;
}

.checkmark {
  position: absolute;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  height: 20px;
  width: 20px;
  background-color: var(--input-bg);
  border: 1px solid var(--input-border);
  border-radius: 6px;
  transition: var(--transition-fast);
}

.custom-checkbox:hover input ~ .checkmark {
  border-color: rgba(255, 255, 255, 0.25);
}

.custom-checkbox input:checked ~ .checkmark {
  background: var(--primary-gradient);
  border-color: transparent;
  box-shadow: 0 0 8px var(--glow-color);
}

.checkmark::after {
  content: "";
  position: absolute;
  display: none;
}

.custom-checkbox input:checked ~ .checkmark::after {
  display: block;
}

.custom-checkbox .checkmark::after {
  left: 7px;
  top: 3px;
  width: 5px;
  height: 10px;
  border: solid white;
  border-width: 0 2px 2px 0;
  transform: rotate(45deg);
}

.custom-checkbox input:checked ~ .label-text {
  color: var(--text-primary);
}

.custom-checkbox .label-text {
  transition: var(--transition-fast);
}

/* ==========================================================================
   Buttons (Icon / Primary Action)
   ========================================================================== */
.icon-btn {
  background: transparent;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  width: 36px;
  height: 36px;
  border-radius: 50%;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: var(--transition-fast);
}

.icon-btn:hover {
  background: rgba(255, 255, 255, 0.05);
  color: var(--accent-color);
}

.icon-btn:active {
  transform: scale(0.9);
}

.icon-btn svg {
  width: 18px;
  height: 18px;
}

.primary-btn {
  background: var(--primary-gradient);
  border: none;
  color: #ffffff;
  font-family: var(--font-heading);
  font-size: 1.05rem;
  font-weight: 700;
  padding: 14px 28px;
  border-radius: 14px;
  cursor: pointer;
  display: flex;
  justify-content: center;
  align-items: center;
  gap: 10px;
  box-shadow: 0 4px 15px var(--glow-color);
  transition: var(--transition-smooth);
  position: relative;
  overflow: hidden;
  width: 100%;
}

.primary-btn::before {
  content: '';
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(
    90deg,
    transparent,
    rgba(255, 255, 255, 0.2),
    transparent
  );
  transition: 0.5s;
}

.primary-btn:hover::before {
  left: 100%;
}

.primary-btn:hover {
  transform: translateY(-2px);
  box-shadow: 0 6px 20px var(--glow-color), 0 0 10px rgba(139, 92, 246, 0.4);
  background: var(--btn-hover-gradient);
}

.primary-btn:active {
  transform: translateY(0);
}

.btn-icon {
  width: 18px;
  height: 18px;
  transition: var(--transition-smooth);
}

.primary-btn:hover .btn-icon {
  transform: translateX(3px);
}

/* ==========================================================================
   Footer
   ========================================================================== */
.app-footer {
  text-align: center;
  color: var(--text-muted);
  font-size: 0.75rem;
  margin-top: 10px;
}

/* ==========================================================================
   Animations
   ========================================================================== */
@keyframes float {
  0%, 100% {
    transform: translateY(0);
  }
  50% {
    transform: translateY(-6px);
  }
}

@keyframes numberPop {
  0% {
    transform: scale(0.6);
    opacity: 0;
    filter: blur(8px);
  }
  100% {
    transform: scale(1);
    opacity: 1;
    filter: blur(0);
  }
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(6px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}