/* ═══════════════════════════════════════════════════════════════════════════════
   DocCompressor – Premium Dark-Mode Stylesheet
   Mobile-first, thumb-friendly, glass-morphism design system
   ═══════════════════════════════════════════════════════════════════════════════ */

/* ─── CSS Custom Properties (Design Tokens) ────────────────────────────────── */
:root {
  /* Core palette */
  --bg-base: #06060b;
  --bg-surface: #0d0d14;
  --bg-elevated: #13131e;
  --bg-card: #181825;
  --bg-card-hover: #1e1e2e;

  /* Accent gradients */
  --accent-primary: #6c63ff;
  --accent-secondary: #a78bfa;
  --accent-tertiary: #38bdf8;
  --gradient-brand: linear-gradient(135deg, #6c63ff 0%, #a78bfa 50%, #38bdf8 100%);
  --gradient-brand-subtle: linear-gradient(135deg, rgba(108,99,255,0.15) 0%, rgba(167,139,250,0.08) 100%);
  --gradient-glow: radial-gradient(ellipse at 50% 0%, rgba(108,99,255,0.18) 0%, transparent 60%);

  /* Text */
  --text-primary: #f0f0f5;
  --text-secondary: #9b9bb0;
  --text-muted: #5e5e73;
  --text-accent: #a78bfa;

  /* Borders */
  --border-subtle: rgba(255,255,255,0.06);
  --border-medium: rgba(255,255,255,0.1);
  --border-accent: rgba(108,99,255,0.4);

  /* Status */
  --status-success: #34d399;
  --status-success-bg: rgba(52,211,153,0.1);
  --status-error: #f87171;
  --status-error-bg: rgba(248,113,113,0.1);
  --status-warning: #fbbf24;

  /* Glass */
  --glass-bg: rgba(13,13,20,0.75);
  --glass-blur: 20px;
  --glass-border: rgba(255,255,255,0.08);

  /* Shadows */
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.4);
  --shadow-md: 0 4px 16px rgba(0,0,0,0.5);
  --shadow-lg: 0 8px 32px rgba(0,0,0,0.6);
  --shadow-glow: 0 0 40px rgba(108,99,255,0.15);

  /* Radii */
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 24px;
  --radius-full: 9999px;

  /* Spacing */
  --space-xs: 4px;
  --space-sm: 8px;
  --space-md: 16px;
  --space-lg: 24px;
  --space-xl: 32px;
  --space-2xl: 48px;
  --space-3xl: 64px;

  /* Typography */
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', system-ui, sans-serif;
  --font-mono: 'JetBrains Mono', 'Fira Code', 'SF Mono', monospace;

  /* Transitions */
  --transition-fast: 150ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-base: 250ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 400ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-spring: 500ms cubic-bezier(0.34, 1.56, 0.64, 1);
}

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

html {
  font-size: 16px;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
  text-rendering: optimizeLegibility;
  scroll-behavior: smooth;
}

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

/* Ambient glow behind hero */
body::before {
  content: '';
  position: fixed;
  top: -200px;
  left: 50%;
  transform: translateX(-50%);
  width: 800px;
  height: 600px;
  background: var(--gradient-glow);
  pointer-events: none;
  z-index: 0;
  opacity: 0.7;
}

/* ─── Utility ───────────────────────────────────────────────────────────────── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0,0,0,0);
  border: 0;
}

/* ─── Top Branding Bar ──────────────────────────────────────────────────────── */
.brand-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: var(--space-sm) var(--space-lg);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-bottom: 1px solid var(--glass-border);
}

.brand-bar__logo {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  text-decoration: none;
  color: var(--text-primary);
  font-weight: 700;
  font-size: 1.1rem;
  letter-spacing: -0.02em;
}

.brand-bar__logo-icon {
  width: 32px;
  height: 32px;
  background: var(--gradient-brand);
  border-radius: var(--radius-sm);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  color: white;
  flex-shrink: 0;
  box-shadow: 0 0 12px rgba(108,99,255,0.3);
}

.brand-bar__nav {
  display: flex;
  align-items: center;
  gap: var(--space-md);
}

.brand-bar__link {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 500;
  transition: color var(--transition-fast);
  padding: var(--space-xs) var(--space-sm);
}

.brand-bar__link:hover {
  color: var(--text-accent);
}

/* ─── Main Layout ───────────────────────────────────────────────────────────── */
.app-main {
  position: relative;
  z-index: 1;
  max-width: 720px;
  margin: 0 auto;
  padding: var(--space-xl) var(--space-md) 120px;
}

/* ─── Hero Section ──────────────────────────────────────────────────────────── */
.hero {
  text-align: center;
  padding: var(--space-2xl) 0 var(--space-xl);
}

.hero__badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-xs);
  padding: 6px 14px;
  background: var(--gradient-brand-subtle);
  border: 1px solid var(--border-accent);
  border-radius: var(--radius-full);
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-accent);
  letter-spacing: 0.04em;
  text-transform: uppercase;
  margin-bottom: var(--space-lg);
}

.hero__badge-dot {
  width: 6px;
  height: 6px;
  background: var(--status-success);
  border-radius: 50%;
  animation: pulse-dot 2s ease-in-out infinite;
}

@keyframes pulse-dot {
  0%, 100% { opacity: 1; transform: scale(1); }
  50% { opacity: 0.5; transform: scale(0.8); }
}

.hero__title {
  font-size: clamp(1.75rem, 5vw, 2.5rem);
  font-weight: 800;
  letter-spacing: -0.03em;
  line-height: 1.15;
  margin-bottom: var(--space-md);
}

.hero__title-gradient {
  background: var(--gradient-brand);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

.hero__subtitle {
  color: var(--text-secondary);
  font-size: clamp(0.9rem, 2.5vw, 1.05rem);
  max-width: 500px;
  margin: 0 auto;
  line-height: 1.7;
}

/* ─── Mode Tabs ─────────────────────────────────────────────────────────────── */
.mode-tabs {
  display: flex;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-lg);
  padding: 4px;
  margin-bottom: var(--space-xl);
  position: relative;
}

.mode-tabs__btn {
  flex: 1;
  position: relative;
  z-index: 2;
  padding: 12px var(--space-md);
  background: transparent;
  border: none;
  border-radius: var(--radius-md);
  color: var(--text-muted);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: color var(--transition-fast);
  min-height: 48px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-xs);
}

.mode-tabs__btn:hover {
  color: var(--text-secondary);
}

.mode-tabs__btn.active {
  color: var(--text-primary);
}

/* Animated slider behind active tab */
.mode-tabs__slider {
  position: absolute;
  top: 4px;
  left: 4px;
  height: calc(100% - 8px);
  width: calc(50% - 4px);
  background: var(--bg-elevated);
  border-radius: var(--radius-md);
  border: 1px solid var(--border-medium);
  transition: transform var(--transition-base);
  z-index: 1;
  box-shadow: var(--shadow-sm);
}

.mode-tabs__slider.right {
  transform: translateX(100%);
}

/* ─── Drop Zone ─────────────────────────────────────────────────────────────── */
.dropzone {
  position: relative;
  border: 2px dashed var(--border-medium);
  border-radius: var(--radius-xl);
  padding: var(--space-3xl) var(--space-lg);
  text-align: center;
  cursor: pointer;
  transition: all var(--transition-base);
  background: var(--bg-surface);
  overflow: hidden;
}

.dropzone::before {
  content: '';
  position: absolute;
  inset: 0;
  background: var(--gradient-brand-subtle);
  opacity: 0;
  transition: opacity var(--transition-base);
  border-radius: var(--radius-xl);
}

.dropzone:hover,
.dropzone.drag-over {
  border-color: var(--accent-primary);
  background: var(--bg-elevated);
  transform: translateY(-2px);
  box-shadow: var(--shadow-glow);
}

.dropzone:hover::before,
.dropzone.drag-over::before {
  opacity: 1;
}

.dropzone__content {
  position: relative;
  z-index: 2;
}

.dropzone__icon {
  font-size: 3rem;
  margin-bottom: var(--space-md);
  display: block;
  filter: grayscale(0.3);
  transition: filter var(--transition-base);
}

.dropzone:hover .dropzone__icon {
  filter: grayscale(0);
}

.dropzone__title {
  font-size: 1.1rem;
  font-weight: 600;
  margin-bottom: var(--space-xs);
  color: var(--text-primary);
}

.dropzone__subtitle {
  font-size: 0.85rem;
  color: var(--text-muted);
}

.dropzone__input {
  position: absolute;
  inset: 0;
  opacity: 0;
  cursor: pointer;
  z-index: 3;
}

/* ─── File List ─────────────────────────────────────────────────────────────── */
.file-list {
  display: flex;
  flex-direction: column;
  gap: var(--space-sm);
  margin-top: var(--space-lg);
}

.file-card {
  display: flex;
  align-items: center;
  gap: var(--space-md);
  padding: var(--space-md);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  transition: all var(--transition-fast);
  animation: slideUp 0.3s var(--transition-base) both;
}

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

@keyframes slideUp {
  from {
    opacity: 0;
    transform: translateY(12px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

.file-card__icon {
  width: 40px;
  height: 40px;
  border-radius: var(--radius-sm);
  background: linear-gradient(135deg, rgba(248,113,113,0.15), rgba(248,113,113,0.05));
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.1rem;
  flex-shrink: 0;
}

.file-card__info {
  flex: 1;
  min-width: 0;
}

.file-card__name {
  font-size: 0.88rem;
  font-weight: 600;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.file-card__size {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-family: var(--font-mono);
}

.file-card__remove {
  width: 32px;
  height: 32px;
  border-radius: var(--radius-sm);
  background: transparent;
  border: 1px solid transparent;
  color: var(--text-muted);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
  transition: all var(--transition-fast);
  flex-shrink: 0;
}

.file-card__remove:hover {
  background: var(--status-error-bg);
  border-color: rgba(248,113,113,0.2);
  color: var(--status-error);
}

/* Merge mode – drag handle */
.file-card__drag {
  cursor: grab;
  color: var(--text-muted);
  font-size: 1.1rem;
  padding: 0 4px;
  user-select: none;
  flex-shrink: 0;
}

.file-card__drag:active {
  cursor: grabbing;
}

.file-card.dragging {
  opacity: 0.5;
  border-color: var(--accent-primary);
  background: var(--bg-elevated);
}

/* ─── Action Button ─────────────────────────────────────────────────────────── */
.action-bar {
  margin-top: var(--space-xl);
  display: flex;
  flex-direction: column;
  gap: var(--space-md);
}

.btn-primary {
  width: 100%;
  padding: 16px var(--space-lg);
  background: var(--gradient-brand);
  border: none;
  border-radius: var(--radius-md);
  color: white;
  font-family: var(--font-sans);
  font-size: 1rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-base);
  min-height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  box-shadow: 0 4px 20px rgba(108,99,255,0.3);
  position: relative;
  overflow: hidden;
}

.btn-primary::before {
  content: '';
  position: absolute;
  inset: 0;
  background: linear-gradient(135deg, rgba(255,255,255,0.1), transparent);
  opacity: 0;
  transition: opacity var(--transition-fast);
}

.btn-primary:hover:not(:disabled) {
  transform: translateY(-2px);
  box-shadow: 0 6px 30px rgba(108,99,255,0.4);
}

.btn-primary:hover:not(:disabled)::before {
  opacity: 1;
}

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

.btn-primary:disabled {
  opacity: 0.4;
  cursor: not-allowed;
  box-shadow: none;
}

.btn-secondary {
  width: 100%;
  padding: 14px var(--space-lg);
  background: var(--bg-card);
  border: 1px solid var(--border-medium);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition-base);
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.btn-secondary:hover {
  background: var(--bg-card-hover);
  border-color: var(--border-accent);
}

/* ─── Progress Overlay ──────────────────────────────────────────────────────── */
.progress-overlay {
  position: fixed;
  inset: 0;
  z-index: 200;
  display: none;
  align-items: center;
  justify-content: center;
  background: rgba(6,6,11,0.85);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
}

.progress-overlay.active {
  display: flex;
  animation: fadeIn 0.3s ease;
}

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

.progress-card {
  width: 90%;
  max-width: 400px;
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: var(--space-2xl) var(--space-xl);
  text-align: center;
  box-shadow: var(--shadow-lg), var(--shadow-glow);
}

.progress-card__spinner {
  width: 56px;
  height: 56px;
  margin: 0 auto var(--space-lg);
  border-radius: 50%;
  border: 3px solid var(--border-subtle);
  border-top-color: var(--accent-primary);
  border-right-color: var(--accent-secondary);
  animation: spin 0.9s linear infinite;
}

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

.progress-card__stage {
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: var(--space-xs);
}

.progress-card__detail {
  font-size: 0.82rem;
  color: var(--text-muted);
  margin-bottom: var(--space-lg);
  min-height: 1.4em;
}

.progress-bar {
  height: 6px;
  background: var(--bg-surface);
  border-radius: var(--radius-full);
  overflow: hidden;
}

.progress-bar__fill {
  height: 100%;
  width: 0%;
  background: var(--gradient-brand);
  border-radius: var(--radius-full);
  transition: width var(--transition-base);
}

.progress-card__percent {
  font-size: 0.78rem;
  font-family: var(--font-mono);
  color: var(--text-muted);
  margin-top: var(--space-sm);
}

/* ─── Result Card ───────────────────────────────────────────────────────────── */
.result-card {
  display: none;
  margin-top: var(--space-xl);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-xl);
  padding: var(--space-xl);
  animation: slideUp 0.4s ease both;
}

.result-card.visible {
  display: block;
}

.result-card__header {
  display: flex;
  align-items: center;
  gap: var(--space-sm);
  margin-bottom: var(--space-lg);
  font-size: 1rem;
  font-weight: 700;
}

.result-card__check {
  width: 28px;
  height: 28px;
  border-radius: 50%;
  background: var(--status-success-bg);
  color: var(--status-success);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1rem;
}

.result-metrics {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  gap: var(--space-md);
  align-items: center;
  margin-bottom: var(--space-lg);
}

.result-metric {
  text-align: center;
  padding: var(--space-md);
  background: var(--bg-surface);
  border-radius: var(--radius-md);
}

.result-metric__label {
  font-size: 0.72rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-muted);
  margin-bottom: var(--space-xs);
}

.result-metric__value {
  font-size: 1.25rem;
  font-weight: 800;
  font-family: var(--font-mono);
  color: var(--text-primary);
}

.result-metric__value.saved {
  color: var(--status-success);
}

.result-metric__value.grew {
  color: var(--status-warning);
}

.result-arrow {
  font-size: 1.2rem;
  color: var(--text-muted);
}

.result-card__download {
  width: 100%;
  padding: 14px;
  background: var(--status-success);
  border: none;
  border-radius: var(--radius-md);
  color: #06060b;
  font-family: var(--font-sans);
  font-size: 0.95rem;
  font-weight: 700;
  cursor: pointer;
  transition: all var(--transition-fast);
  min-height: 52px;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
}

.result-card__download:hover {
  background: #5ee8b5;
  transform: translateY(-1px);
  box-shadow: 0 4px 16px rgba(52,211,153,0.3);
}

/* ─── Privacy Badge ─────────────────────────────────────────────────────────── */
.privacy-badge {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-sm);
  padding: var(--space-md);
  margin-top: var(--space-xl);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  font-size: 0.8rem;
  color: var(--text-muted);
}

.privacy-badge__icon {
  font-size: 1rem;
}

/* ─── Bottom Branding Bar ───────────────────────────────────────────────────── */
.brand-footer {
  position: fixed;
  bottom: 0;
  left: 0;
  right: 0;
  z-index: 100;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: var(--space-sm) var(--space-md);
  background: var(--glass-bg);
  backdrop-filter: blur(var(--glass-blur));
  -webkit-backdrop-filter: blur(var(--glass-blur));
  border-top: 1px solid var(--glass-border);
  font-size: 0.78rem;
  color: var(--text-muted);
  gap: var(--space-xs);
}

.brand-footer a {
  color: var(--text-accent);
  text-decoration: none;
  font-weight: 600;
  transition: color var(--transition-fast);
}

.brand-footer a:hover {
  color: var(--accent-primary);
}

/* ─── Toast Notification ────────────────────────────────────────────────────── */
.toast {
  position: fixed;
  bottom: 60px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  z-index: 300;
  padding: var(--space-md) var(--space-lg);
  background: var(--bg-card);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  font-size: 0.85rem;
  color: var(--text-primary);
  box-shadow: var(--shadow-lg);
  opacity: 0;
  pointer-events: none;
  transition: all var(--transition-spring);
  white-space: nowrap;
}

.toast.visible {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
  pointer-events: auto;
}

.toast.error {
  border-color: rgba(248,113,113,0.3);
}

/* ─── Feature Highlights ────────────────────────────────────────────────────── */
.features {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: var(--space-md);
  margin: var(--space-xl) 0;
}

.feature-chip {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: var(--space-xs);
  padding: var(--space-md) var(--space-sm);
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: var(--radius-md);
  text-align: center;
  transition: all var(--transition-fast);
}

.feature-chip:hover {
  border-color: var(--border-accent);
  background: var(--bg-elevated);
  transform: translateY(-2px);
}

.feature-chip__icon {
  font-size: 1.5rem;
}

.feature-chip__label {
  font-size: 0.72rem;
  font-weight: 600;
  color: var(--text-secondary);
  letter-spacing: 0.02em;
}

/* ─── Responsive ────────────────────────────────────────────────────────────── */
@media (max-width: 480px) {
  .app-main {
    padding: var(--space-lg) var(--space-md) 120px;
  }

  .hero {
    padding: var(--space-lg) 0;
  }

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

  .result-metrics {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }

  .result-arrow {
    transform: rotate(90deg);
    justify-self: center;
  }

  .features {
    grid-template-columns: 1fr;
    gap: var(--space-sm);
  }

  .feature-chip {
    flex-direction: row;
    text-align: left;
    padding: var(--space-md);
  }

  .brand-bar__nav {
    gap: var(--space-sm);
  }

  .brand-bar__link {
    font-size: 0.78rem;
  }
}

@media (min-width: 481px) and (max-width: 768px) {
  .features {
    grid-template-columns: repeat(3, 1fr);
  }
}

/* ─── Install Prompt ────────────────────────────────────────────────────────── */
.install-prompt {
  display: none;
  margin-top: var(--space-md);
}

.install-prompt.visible {
  display: block;
}

/* ─── Animations ────────────────────────────────────────────────────────────── */
@keyframes shimmer {
  0% { background-position: -200% 0; }
  100% { background-position: 200% 0; }
}

.shimmer {
  background: linear-gradient(
    90deg,
    var(--bg-surface) 25%,
    var(--bg-elevated) 50%,
    var(--bg-surface) 75%
  );
  background-size: 200% 100%;
  animation: shimmer 1.5s ease-in-out infinite;
}

/* Focus styles for accessibility */
:focus-visible {
  outline: 2px solid var(--accent-primary);
  outline-offset: 2px;
}

/* Scrollbar styling */
::-webkit-scrollbar {
  width: 6px;
}

::-webkit-scrollbar-track {
  background: var(--bg-base);
}

::-webkit-scrollbar-thumb {
  background: var(--border-medium);
  border-radius: var(--radius-full);
}

::-webkit-scrollbar-thumb:hover {
  background: var(--text-muted);
}