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

:root {
  /* Colors */
  --bg-primary: #0a0a0f;
  --bg-secondary: #12121a;
  --bg-card: rgba(255, 255, 255, 0.03);
  --bg-card-hover: rgba(255, 255, 255, 0.05);

  --text-primary: #f0f0f5;
  --text-secondary: #8888a0;
  --text-muted: #55556a;

  --accent-primary: #6366f1;
  --accent-secondary: #818cf8;
  --accent-glow: rgba(99, 102, 241, 0.4);

  --success: #22c55e;
  --error: #ef4444;
  --error-bg: rgba(239, 68, 68, 0.1);

  --pdf-color: #ef4444;
  --epub-color: #22c55e;

  --border: rgba(255, 255, 255, 0.08);
  --border-focus: rgba(99, 102, 241, 0.5);

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

  /* Border Radius */
  --radius-sm: 0.375rem;
  --radius-md: 0.75rem;
  --radius-lg: 1rem;
  --radius-xl: 1.5rem;

  /* Transitions */
  --transition-fast: 150ms ease;
  --transition-normal: 250ms ease;
  --transition-slow: 400ms ease;

  /* Font */
  --font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
}

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

body {
  font-family: var(--font-family);
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

/* Background Glow Effect */
.background-glow {
  position: fixed;
  top: -50%;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 800px;
  background: radial-gradient(circle, var(--accent-glow) 0%, transparent 70%);
  pointer-events: none;
  z-index: 0;
  opacity: 0.6;
}

/* Container */
.container {
  position: relative;
  z-index: 1;
  max-width: 640px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md);
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
.header {
  text-align: center;
  margin-bottom: var(--space-2xl);
}

.logo {
  display: inline-flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-sm);
}

.logo-icon {
  width: 32px;
  height: 32px;
  color: var(--accent-primary);
}

.logo h1 {
  font-size: 1.75rem;
  font-weight: 700;
  background: linear-gradient(135deg, var(--text-primary) 0%, var(--accent-secondary) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.subtitle {
  color: var(--text-secondary);
  font-size: 0.95rem;
}

/* Card */
.card {
  background: var(--bg-card);
  backdrop-filter: blur(20px);
  border: 1px solid var(--border);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  transition: background var(--transition-normal);
}

.card:hover {
  background: var(--bg-card-hover);
}

/* Form */
.form {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
}

.label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.input-group {
  display: flex;
  gap: var(--space-sm);
}

.input {
  flex: 1;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-size: 0.95rem;
  font-family: inherit;
  transition: all var(--transition-fast);
  outline: none;
}

.input::placeholder {
  color: var(--text-muted);
}

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

.hint {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md) var(--space-lg);
  border: none;
  border-radius: var(--radius-md);
  font-size: 0.95rem;
  font-weight: 600;
  font-family: inherit;
  cursor: pointer;
  transition: all var(--transition-fast);
  outline: none;
  white-space: nowrap;
}

.btn-primary {
  background: linear-gradient(135deg, var(--accent-primary) 0%, var(--accent-secondary) 100%);
  color: white;
  min-width: 100px;
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-1px);
  box-shadow: 0 4px 20px var(--accent-glow);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(0);
}

.btn-primary:disabled {
  opacity: 0.7;
  cursor: not-allowed;
}

.btn-primary.loading .btn-text {
  display: none;
}

.btn-primary.loading .btn-loader {
  display: block;
}

.btn-loader {
  display: none;
  width: 18px;
  height: 18px;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-top-color: white;
  border-radius: 50%;
  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to {
    transform: rotate(360deg);
  }
}

.btn-copy {
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  color: var(--text-secondary);
  padding: var(--space-sm) var(--space-md);
}

.btn-copy:hover {
  background: var(--bg-card-hover);
  color: var(--text-primary);
}

.btn-copy .copy-icon,
.btn-copy .check-icon {
  width: 18px;
  height: 18px;
}

.btn-copy .check-icon {
  color: var(--success);
}

.btn-copy .hidden {
  display: none;
}

/* Badges */
.badge {
  display: inline-flex;
  align-items: center;
  padding: 0.2rem 0.6rem;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  border-radius: var(--radius-sm);
}

.badge-pdf {
  background: rgba(239, 68, 68, 0.15);
  color: var(--pdf-color);
  border: 1px solid rgba(239, 68, 68, 0.3);
}

.badge-epub {
  background: rgba(34, 197, 94, 0.15);
  color: var(--epub-color);
  border: 1px solid rgba(34, 197, 94, 0.3);
}

/* Result */
.result {
  margin-top: var(--space-xl);
  padding-top: var(--space-xl);
  border-top: 1px solid var(--border);
  animation: fadeIn var(--transition-normal);
}

.result.hidden {
  display: none;
}

@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(10px);
  }

  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.result-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: var(--space-sm);
  flex-wrap: wrap;
  gap: var(--space-sm);
}

.result-label-group {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
}

.result-label {
  font-size: 0.875rem;
  font-weight: 500;
  color: var(--text-secondary);
}

.result-actions {
  display: flex;
  gap: var(--space-sm);
}

.file-url {
  display: block;
  padding: var(--space-md);
  background: var(--bg-secondary);
  border: 1px solid var(--border);
  border-radius: var(--radius-md);
  color: var(--accent-secondary);
  font-size: 0.875rem;
  word-break: break-all;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.file-url:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-focus);
}

/* Metadata */
.metadata {
  margin-top: var(--space-lg);
  padding: var(--space-lg);
  background: var(--bg-secondary);
  border-radius: var(--radius-md);
}

.metadata-title {
  font-size: 0.875rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: var(--space-md);
}

.metadata-list {
  display: grid;
  gap: var(--space-sm);
}

.metadata-item {
  display: grid;
  grid-template-columns: 80px 1fr;
  gap: var(--space-md);
  font-size: 0.875rem;
}

.metadata-item dt {
  color: var(--text-muted);
}

.metadata-item dd {
  color: var(--text-primary);
}

/* Error */
.error {
  display: flex;
  align-items: flex-start;
  gap: var(--space-md);
  margin-top: var(--space-xl);
  padding: var(--space-lg);
  background: var(--error-bg);
  border: 1px solid rgba(239, 68, 68, 0.2);
  border-radius: var(--radius-md);
  color: var(--error);
  animation: shake 0.4s ease;
}

.error.hidden {
  display: none;
}

@keyframes shake {

  0%,
  100% {
    transform: translateX(0);
  }

  20% {
    transform: translateX(-5px);
  }

  40% {
    transform: translateX(5px);
  }

  60% {
    transform: translateX(-5px);
  }

  80% {
    transform: translateX(5px);
  }
}

.error-icon {
  width: 20px;
  height: 20px;
  flex-shrink: 0;
}

.error p {
  font-size: 0.875rem;
  line-height: 1.5;
}

/* Footer */
.footer {
  margin-top: auto;
  padding-top: var(--space-2xl);
  text-align: center;
}

.footer p {
  font-size: 0.8rem;
  color: var(--text-muted);
}

/* Responsive */
@media (max-width: 480px) {
  .input-group {
    flex-direction: column;
  }

  .btn-primary {
    width: 100%;
  }

  .metadata-item {
    grid-template-columns: 1fr;
    gap: var(--space-xs);
  }

  .result-header {
    flex-direction: column;
    align-items: flex-start;
  }

  .result-actions {
    width: 100%;
  }
}