/* Currency Converter - Premium Dark Theme */

/* Design Tokens */
:root {
  --bg-deep: #0a0a1a;
  --bg-card: rgba(255, 255, 255, 0.06);
  --bg-card-border: rgba(255, 255, 255, 0.1);
  --bg-input: rgba(255, 255, 255, 0.07);
  --bg-input-focus: rgba(255, 255, 255, 0.12);
  --text-primary: #f0f0f8;
  --text-secondary: rgba(240, 240, 248, 0.6);
  --text-muted: rgba(240, 240, 248, 0.35);
  --accent-1: #6c5ce7;
  --accent-2: #a855f7;
  --accent-3: #06b6d4;
  --accent-gradient: linear-gradient(135deg, var(--accent-1), var(--accent-2), var(--accent-3));
  --accent-glow: rgba(168, 85, 247, 0.25);
  --success: #10b981;
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-active: rgba(168, 85, 247, 0.4);

  --space-xs: 0.25rem;
  --space-sm: 0.5rem;
  --space-md: 1rem;
  --space-lg: 1.5rem;
  --space-xl: 2rem;
  --space-2xl: 3rem;

  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-xs: 0.75rem;
  --font-sm: 0.85rem;
  --font-base: 1rem;
  --font-lg: 1.125rem;
  --font-xl: 1.5rem;
  --font-2xl: 2rem;

  --radius-sm: 0.75rem;
  --radius-md: 1rem;
  --radius-lg: 1.5rem;
  --radius-xl: 2rem;
  --radius-full: 50%;

  --shadow-card: 0 8px 32px rgba(0, 0, 0, 0.4), 0 0 0 1px var(--bg-card-border);
  --shadow-input: 0 2px 8px rgba(0, 0, 0, 0.2);
  --shadow-btn: 0 4px 20px rgba(108, 92, 231, 0.35);
  --shadow-btn-hover: 0 8px 30px rgba(108, 92, 231, 0.5);
  --shadow-glow: 0 0 60px var(--accent-glow);

  --ease-out: cubic-bezier(0.16, 1, 0.3, 1);
  --ease-spring: cubic-bezier(0.34, 1.56, 0.64, 1);
  --transition-fast: 200ms var(--ease-out);
  --transition-normal: 350ms var(--ease-out);
  --transition-slow: 500ms var(--ease-out);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

body {
  font-family: var(--font-family);
  background: var(--bg-deep);
  color: var(--text-primary);
  min-height: 100vh;
  display: flex;
  justify-content: center;
  align-items: center;
  overflow-x: hidden;
  position: relative;
}

/* Animated background orbs that float around the page */
.bg-orbs {
  position: fixed;
  inset: 0;
  overflow: hidden;
  pointer-events: none;
  z-index: 0;
}

.orb {
  position: absolute;
  border-radius: 50%;
  filter: blur(100px);
  opacity: 0.5;
  animation: float 20s ease-in-out infinite;
}

.orb-1 {
  width: 500px;
  height: 500px;
  background: radial-gradient(circle, var(--accent-1), transparent 70%);
  top: -15%;
  left: -10%;
  animation-duration: 22s;
}

.orb-2 {
  width: 400px;
  height: 400px;
  background: radial-gradient(circle, var(--accent-2), transparent 70%);
  bottom: -10%;
  right: -10%;
  animation-duration: 18s;
  animation-delay: -5s;
}

/* Uses float-center keyframe to preserve translate(-50%, -50%) centering */
.orb-3 {
  width: 350px;
  height: 350px;
  background: radial-gradient(circle, var(--accent-3), transparent 70%);
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  animation: float-center 25s ease-in-out infinite;
  animation-delay: -10s;
}

@keyframes float {
  0%, 100% { transform: translate(0, 0) scale(1); }
  25% { transform: translate(40px, -30px) scale(1.05); }
  50% { transform: translate(-20px, 20px) scale(0.95); }
  75% { transform: translate(30px, 40px) scale(1.02); }
}

/* Separate keyframe for centered orb to maintain offset during animation */
@keyframes float-center {
  0%, 100% { transform: translate(-50%, -50%) scale(1); }
  25% { transform: translate(calc(-50% + 40px), calc(-50% - 30px)) scale(1.05); }
  50% { transform: translate(calc(-50% - 20px), calc(-50% + 20px)) scale(0.95); }
  75% { transform: translate(calc(-50% + 30px), calc(-50% + 40px)) scale(1.02); }
}

/* Main app container */
.app {
  position: relative;
  z-index: 1;
  width: 100%;
  max-width: 480px;
  padding: var(--space-lg);
  animation: fadeInUp 0.8s var(--ease-out) both;
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(30px); }
  to { opacity: 1; transform: translateY(0); }
}

/* Header and logo */
.app-header {
  text-align: center;
  margin-bottom: var(--space-xl);
}

.logo {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-md);
}

.logo-icon {
  width: 52px;
  height: 52px;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: var(--font-xl);
  color: #fff;
  box-shadow: var(--shadow-btn);
  animation: pulse-glow 3s ease-in-out infinite;
}

@keyframes pulse-glow {
  0%, 100% { box-shadow: var(--shadow-btn); }
  50% { box-shadow: var(--shadow-btn-hover); }
}

/* Gradient text effect on the title */
.logo-text h1 {
  font-size: var(--font-xl);
  font-weight: 800;
  background: var(--accent-gradient);
  -webkit-background-clip: text;
  background-clip: text;
  -webkit-text-fill-color: transparent;
  letter-spacing: -0.02em;
  line-height: 1.2;
}

.tagline {
  font-size: var(--font-xs);
  color: var(--text-muted);
  font-weight: 500;
  text-transform: uppercase;
  letter-spacing: 0.1em;
  margin-top: 2px;
}

/* Glassmorphism card */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(40px) saturate(150%);
  -webkit-backdrop-filter: blur(40px) saturate(150%);
  border-radius: var(--radius-xl);
  border: 1px solid var(--bg-card-border);
  padding: var(--space-xl);
  box-shadow: var(--shadow-card);
  transition: box-shadow var(--transition-slow);
}

.card:hover {
  box-shadow: var(--shadow-card), var(--shadow-glow);
}

/* Form labels */
.input-label {
  display: block;
  font-size: var(--font-xs);
  font-weight: 600;
  color: var(--text-secondary);
  text-transform: uppercase;
  letter-spacing: 0.08em;
  margin-bottom: var(--space-sm);
}

/* Amount input field */
.input-wrapper {
  position: relative;
  display: flex;
  align-items: center;
}

.input-icon {
  position: absolute;
  left: var(--space-md);
  color: var(--text-muted);
  font-size: var(--font-base);
  transition: color var(--transition-fast);
  pointer-events: none;
}

.input-wrapper input {
  width: 100%;
  height: 56px;
  padding: 0 var(--space-md) 0 3rem;
  font-family: var(--font-family);
  font-size: var(--font-lg);
  font-weight: 600;
  color: var(--text-primary);
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  outline: none;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-input);
}

.input-wrapper input:focus {
  background: var(--bg-input-focus);
  border-color: var(--border-active);
  box-shadow: var(--shadow-input), 0 0 0 3px rgba(168, 85, 247, 0.1);
}

/* Highlight icon on focus or hover */
.input-wrapper input:focus + .input-icon,
.input-wrapper:hover .input-icon {
  color: var(--accent-2);
}

.input-wrapper input::placeholder {
  color: var(--text-muted);
  font-weight: 400;
}

/* Hide native number input spinners */
input[type="number"]::-webkit-inner-spin-button,
input[type="number"]::-webkit-outer-spin-button {
  -webkit-appearance: none;
  margin: 0;
}

input[type="number"] {
  -moz-appearance: textfield;
}

/* Currency picker row (From / Swap / To) */
.currency-row {
  display: flex;
  align-items: flex-end;
  gap: var(--space-sm);
  margin-top: var(--space-xl);
}

.currency-picker {
  flex: 1;
  min-width: 0;
}

.picker-box {
  position: relative;
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  background: var(--bg-input);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  padding: var(--space-sm) var(--space-md);
  height: 56px;
  transition: all var(--transition-fast);
  box-shadow: var(--shadow-input);
  cursor: pointer;
}

.picker-box:hover,
.picker-box:focus-within {
  background: var(--bg-input-focus);
  border-color: var(--border-active);
}

.flag-img {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  object-fit: cover;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.3);
}

.picker-box select {
  flex: 1;
  min-width: 0;
  background: transparent;
  border: none;
  outline: none;
  font-family: var(--font-family);
  font-size: var(--font-base);
  font-weight: 600;
  color: var(--text-primary);
  cursor: pointer;
  -webkit-appearance: none;
  -moz-appearance: none;
  appearance: none;
}

.picker-box select option {
  background: #1a1a2e;
  color: var(--text-primary);
}

.picker-arrow {
  font-size: var(--font-xs);
  color: var(--text-muted);
  flex-shrink: 0;
  transition: transform var(--transition-fast);
}

.picker-box:focus-within .picker-arrow {
  transform: rotate(180deg);
  color: var(--accent-2);
}

/* Swap button between From and To pickers */
.swap-btn {
  flex-shrink: 0;
  width: 44px;
  height: 44px;
  border-radius: var(--radius-full);
  border: 2px solid var(--border-subtle);
  background: var(--bg-input);
  color: var(--text-secondary);
  font-size: var(--font-base);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all var(--transition-fast);
  margin-bottom: 4px;
}

.swap-btn:hover {
  background: var(--accent-gradient);
  border-color: transparent;
  color: #fff;
  transform: rotate(180deg) scale(1.1);
  box-shadow: var(--shadow-btn);
}

.swap-btn:active {
  transform: rotate(180deg) scale(0.95);
}

/* Conversion result panel */
.result-display {
  margin-top: var(--space-xl);
  position: relative;
  overflow: hidden;
  border-radius: var(--radius-md);
  background: linear-gradient(135deg, rgba(108, 92, 231, 0.1), rgba(6, 182, 212, 0.08));
  border: 1px solid rgba(108, 92, 231, 0.15);
  padding: var(--space-lg);
  text-align: center;
}

.result-content {
  position: relative;
  z-index: 1;
}

.result-text {
  font-size: var(--font-lg);
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.01em;
}

/* Animated shimmer effect across the result panel */
.result-shimmer {
  position: absolute;
  top: 0;
  left: -100%;
  width: 100%;
  height: 100%;
  background: linear-gradient(90deg, transparent, rgba(168, 85, 247, 0.06), transparent);
  animation: shimmer 3s ease-in-out infinite;
}

@keyframes shimmer {
  0% { left: -100%; }
  100% { left: 100%; }
}

/* Convert button with gradient animation */
.convert-btn {
  width: 100%;
  height: 56px;
  margin-top: var(--space-xl);
  border: none;
  border-radius: var(--radius-md);
  background: var(--accent-gradient);
  background-size: 200% 200%;
  color: #fff;
  font-family: var(--font-family);
  font-size: var(--font-lg);
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  transition: all var(--transition-normal);
  box-shadow: var(--shadow-btn);
  position: relative;
  overflow: hidden;
  animation: gradient-shift 4s ease infinite;
}

@keyframes gradient-shift {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* Glossy overlay on hover */
.convert-btn::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(rgba(255, 255, 255, 0.1), transparent);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.convert-btn:hover {
  transform: translateY(-2px);
  box-shadow: var(--shadow-btn-hover);
}

.convert-btn:hover::before {
  opacity: 1;
}

.convert-btn:active {
  transform: translateY(0) scale(0.98);
}

.btn-arrow {
  transition: transform var(--transition-fast);
}

.convert-btn:hover .btn-arrow {
  transform: translateX(4px);
}

/* Loading state: hide text, show spinner */
.btn-loader {
  display: none;
}

.convert-btn.loading .btn-text,
.convert-btn.loading .btn-arrow {
  display: none;
}

.convert-btn.loading .btn-loader {
  display: inline-flex;
}

/* Footer */
.app-footer {
  text-align: center;
  margin-top: var(--space-xl);
}

.app-footer p {
  font-size: var(--font-xs);
  color: var(--text-muted);
  font-weight: 500;
}

/* Responsive: tablets and small screens */
@media (max-width: 540px) {
  .app {
    padding: var(--space-md);
  }

  .card {
    padding: var(--space-lg);
    border-radius: var(--radius-lg);
  }

  .logo-icon {
    width: 44px;
    height: 44px;
    font-size: var(--font-lg);
  }

  .logo-text h1 {
    font-size: var(--font-lg);
  }

  .currency-row {
    flex-direction: column;
    gap: var(--space-md);
    align-items: stretch;
  }

  .swap-btn {
    align-self: center;
    transform: rotate(90deg);
    margin-bottom: 0;
  }

  .swap-btn:hover {
    transform: rotate(270deg) scale(1.1);
  }

  .result-text {
    font-size: var(--font-base);
  }
}

/* Responsive: very small screens */
@media (max-width: 360px) {
  :root {
    font-size: 14px;
  }

  .card {
    padding: var(--space-md);
  }
}

/* Responsive: large screens */
@media (min-width: 768px) {
  .app {
    max-width: 520px;
  }

  .card {
    padding: var(--space-2xl);
  }
}

/* Accessibility: respect user's motion preferences */
@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.01ms !important;
  }
}

/* Keyboard focus indicator */
:focus-visible {
  outline: 2px solid var(--accent-2);
  outline-offset: 2px;
}