/* ==========================================================================
   Fleex-Webp Converter — Modern Browser-Based Image to WebP Converter
   Stylesheet (style.css)
   ========================================================================== */

/* 1. Root Design Tokens & Color Scheme (modern-web-guidance: dark-mode) */
:root {
  /* Raw light/dark palette tokens */
  --brand-light: #4f46e5;       /* Indigo 600 */
  --brand-dark: #818cf8;        /* Indigo 400 */
  --brand-hover-light: #4338ca; /* Indigo 700 */
  --brand-hover-dark: #a5b4fc;  /* Indigo 300 */
  --accent-pink-light: #db2777; /* Pink 600 */
  --accent-pink-dark: #f472b6;  /* Pink 400 */

  --bg-base-light: #f5f3ff;
  --bg-base-dark: #0b0914;

  --text-primary-light: #1e1b4b;
  --text-primary-dark: #f8fafc;

  --text-secondary-light: #475569;
  --text-secondary-dark: #cbd5e1;

  --text-muted-light: #64748b;
  --text-muted-dark: #94a3b8;

  --glass-bg-light: rgba(255, 255, 255, 0.72);
  --glass-bg-dark: rgba(20, 18, 38, 0.68);

  --glass-bg-elevated-light: rgba(255, 255, 255, 0.88);
  --glass-bg-elevated-dark: rgba(30, 27, 56, 0.84);

  --glass-border-light: rgba(99, 102, 241, 0.22);
  --glass-border-dark: rgba(165, 180, 252, 0.18);

  --control-border-light: rgba(79, 70, 229, 0.38);
  --control-border-dark: rgba(148, 163, 184, 0.42);

  --shadow-card-light: 0 20px 45px -15px rgba(79, 70, 229, 0.12), 0 4px 16px -4px rgba(15, 23, 42, 0.06);
  --shadow-card-dark: 0 24px 48px -12px rgba(0, 0, 0, 0.55), 0 4px 16px -4px rgba(0, 0, 0, 0.4);

  --success-bg-light: rgba(16, 185, 129, 0.14);
  --success-bg-dark: rgba(16, 185, 129, 0.2);
  --success-text-light: #047857;
  --success-text-dark: #6ee7b7;

  --warning-bg-light: rgba(245, 158, 11, 0.15);
  --warning-bg-dark: rgba(245, 158, 11, 0.22);
  --warning-text-light: #b45309;
  --warning-text-dark: #fcd34d;

  --danger-bg-light: rgba(239, 68, 68, 0.14);
  --danger-bg-dark: rgba(239, 68, 68, 0.22);
  --danger-text-light: #b91c1c;
  --danger-text-dark: #fca5a5;

  --scrollbar-thumb-light: #94a3b8;
  --scrollbar-thumb-dark: #475569;
  --scrollbar-track-light: #f1f5f9;
  --scrollbar-track-dark: #1e1b4b;

  /* Default to light tokens before media query / light-dark() resolution */
  --color-brand: var(--brand-light);
  --color-brand-hover: var(--brand-hover-light);
  --color-accent-pink: var(--accent-pink-light);
  --bg-base: var(--bg-base-light);
  --text-primary: var(--text-primary-light);
  --text-secondary: var(--text-secondary-light);
  --text-muted: var(--text-muted-light);
  --glass-bg: var(--glass-bg-light);
  --glass-bg-elevated: var(--glass-bg-elevated-light);
  --glass-border: var(--glass-border-light);
  --control-border: var(--control-border-light);
  --shadow-card: var(--shadow-card-light);
  --success-bg: var(--success-bg-light);
  --success-text: var(--success-text-light);
  --warning-bg: var(--warning-bg-light);
  --warning-text: var(--warning-text-light);
  --danger-bg: var(--danger-bg-light);
  --danger-text: var(--danger-text-light);
  --scrollbar-thumb: var(--scrollbar-thumb-light);
  --scrollbar-track: var(--scrollbar-track-light);

  --bg-gradient: linear-gradient(135deg, #eef2ff 0%, #f5f3ff 38%, #fae8ff 72%, #fce7f3 100%);
  --checker-a: rgba(148, 163, 184, 0.16);
  --checker-b: rgba(255, 255, 255, 0.6);

  /* Layout & Radius tokens */
  --radius-sm: 0.625rem;
  --radius-md: 1rem;
  --radius-lg: 1.375rem;
  --radius-xl: 1.75rem;
  --radius-pill: 9999px;

  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;

  /* MANDATORY: Fallback for browsers without light-dark() support */
  @media (prefers-color-scheme: dark) {
    --color-brand: var(--brand-dark);
    --color-brand-hover: var(--brand-hover-dark);
    --color-accent-pink: var(--accent-pink-dark);
    --bg-base: var(--bg-base-dark);
    --text-primary: var(--text-primary-dark);
    --text-secondary: var(--text-secondary-dark);
    --text-muted: var(--text-muted-dark);
    --glass-bg: var(--glass-bg-dark);
    --glass-bg-elevated: var(--glass-bg-elevated-dark);
    --glass-border: var(--glass-border-dark);
    --control-border: var(--control-border-dark);
    --shadow-card: var(--shadow-card-dark);
    --success-bg: var(--success-bg-dark);
    --success-text: var(--success-text-dark);
    --warning-bg: var(--warning-bg-dark);
    --warning-text: var(--warning-text-dark);
    --danger-bg: var(--danger-bg-dark);
    --danger-text: var(--danger-text-dark);
    --scrollbar-thumb: var(--scrollbar-thumb-dark);
    --scrollbar-track: var(--scrollbar-track-dark);
    --bg-gradient: linear-gradient(135deg, #090d16 0%, #131129 40%, #1e1333 75%, #27112b 100%);
    --checker-a: rgba(255, 255, 255, 0.07);
    --checker-b: rgba(15, 23, 42, 0.55);
  }

  /* Modern light-dark() automatic resolution based on computed color-scheme */
  @supports (color: light-dark(white, black)) {
    --color-brand: light-dark(var(--brand-light), var(--brand-dark));
    --color-brand-hover: light-dark(var(--brand-hover-light), var(--brand-hover-dark));
    --color-accent-pink: light-dark(var(--accent-pink-light), var(--accent-pink-dark));
    --bg-base: light-dark(var(--bg-base-light), var(--bg-base-dark));
    --text-primary: light-dark(var(--text-primary-light), var(--text-primary-dark));
    --text-secondary: light-dark(var(--text-secondary-light), var(--text-secondary-dark));
    --text-muted: light-dark(var(--text-muted-light), var(--text-muted-dark));
    --glass-bg: light-dark(var(--glass-bg-light), var(--glass-bg-dark));
    --glass-bg-elevated: light-dark(var(--glass-bg-elevated-light), var(--glass-bg-elevated-dark));
    --glass-border: light-dark(var(--glass-border-light), var(--glass-border-dark));
    --control-border: light-dark(var(--control-border-light), var(--control-border-dark));
    --shadow-card: light-dark(var(--shadow-card-light), var(--shadow-card-dark));
    --success-bg: light-dark(var(--success-bg-light), var(--success-bg-dark));
    --success-text: light-dark(var(--success-text-light), var(--success-text-dark));
    --warning-bg: light-dark(var(--warning-bg-light), var(--warning-bg-dark));
    --warning-text: light-dark(var(--warning-text-light), var(--warning-text-dark));
    --danger-bg: light-dark(var(--danger-bg-light), var(--danger-bg-dark));
    --danger-text: light-dark(var(--danger-text-light), var(--danger-text-dark));
    --scrollbar-thumb: light-dark(var(--scrollbar-thumb-light), var(--scrollbar-thumb-dark));
    --scrollbar-track: light-dark(var(--scrollbar-track-light), var(--scrollbar-track-dark));
  }

  /* MANDATORY: Apply color-scheme to :root for viewport-wide native UI theming */
  color-scheme: light dark;
  accent-color: var(--color-brand);

  /* Custom scrollbar colors paired with scrollbar-width for macOS compatibility */
  scrollbar-width: thin;
  scrollbar-color: var(--scrollbar-thumb) var(--scrollbar-track);
}

/* Explicit theme attribute overrides when user toggles Light or Dark mode */
html[data-theme="light"] {
  color-scheme: light;
  --color-brand: var(--brand-light);
  --color-brand-hover: var(--brand-hover-light);
  --color-accent-pink: var(--accent-pink-light);
  --bg-base: var(--bg-base-light);
  --text-primary: var(--text-primary-light);
  --text-secondary: var(--text-secondary-light);
  --text-muted: var(--text-muted-light);
  --glass-bg: var(--glass-bg-light);
  --glass-bg-elevated: var(--glass-bg-elevated-light);
  --glass-border: var(--glass-border-light);
  --control-border: var(--control-border-light);
  --shadow-card: var(--shadow-card-light);
  --success-bg: var(--success-bg-light);
  --success-text: var(--success-text-light);
  --warning-bg: var(--warning-bg-light);
  --warning-text: var(--warning-text-light);
  --danger-bg: var(--danger-bg-light);
  --danger-text: var(--danger-text-light);
  --scrollbar-thumb: var(--scrollbar-thumb-light);
  --scrollbar-track: var(--scrollbar-track-light);
  --bg-gradient: linear-gradient(135deg, #eef2ff 0%, #f5f3ff 38%, #fae8ff 72%, #fce7f3 100%);
  --checker-a: rgba(148, 163, 184, 0.16);
  --checker-b: rgba(255, 255, 255, 0.6);
  accent-color: var(--color-brand);
}

html[data-theme="dark"] {
  color-scheme: dark;
  --color-brand: var(--brand-dark);
  --color-brand-hover: var(--brand-hover-dark);
  --color-accent-pink: var(--accent-pink-dark);
  --bg-base: var(--bg-base-dark);
  --text-primary: var(--text-primary-dark);
  --text-secondary: var(--text-secondary-dark);
  --text-muted: var(--text-muted-dark);
  --glass-bg: var(--glass-bg-dark);
  --glass-bg-elevated: var(--glass-bg-elevated-dark);
  --glass-border: var(--glass-border-dark);
  --control-border: var(--control-border-dark);
  --shadow-card: var(--shadow-card-dark);
  --success-bg: var(--success-bg-dark);
  --success-text: var(--success-text-dark);
  --warning-bg: var(--warning-bg-dark);
  --warning-text: var(--warning-text-dark);
  --danger-bg: var(--danger-bg-dark);
  --danger-text: var(--danger-text-dark);
  --scrollbar-thumb: var(--scrollbar-thumb-dark);
  --scrollbar-track: var(--scrollbar-track-dark);
  --bg-gradient: linear-gradient(135deg, #090d16 0%, #131129 40%, #1e1333 75%, #27112b 100%);
  --checker-a: rgba(255, 255, 255, 0.07);
  --checker-b: rgba(15, 23, 42, 0.55);
  accent-color: var(--color-brand);
}

/* Legacy fallback for WebKit/Blink scrollbars when scrollbar-color is unsupported */
@supports not (scrollbar-color: auto) {
  ::-webkit-scrollbar {
    width: 10px;
    height: 10px;
  }
  ::-webkit-scrollbar-thumb {
    background: var(--scrollbar-thumb);
    border-radius: 5px;
  }
  ::-webkit-scrollbar-track {
    background: var(--scrollbar-track);
  }
}

/* 2. Reset & Base Typography */
*,
*::before,
*::after {
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

html {
  font-size: 100%;
  -webkit-text-size-adjust: 100%;
  scroll-behavior: smooth;
}

body {
  min-block-size: 100dvh;
  display: flex;
  flex-direction: column;
  font-family: var(--font-sans);
  background-color: var(--bg-base);
  background-image: var(--bg-gradient);
  background-attachment: fixed;
  color: var(--text-primary);
  line-height: 1.5;
  text-align: start;
  overflow-x: clip;
  position: relative;
  accent-color: var(--color-brand);
  transition: background-color 0.25s ease, color 0.25s ease;
}

/* Balanced headings & pretty body text (modern-web-guidance: improve-text-layout-and-legibility) */
h1, h2, h3, h4, h5, h6 {
  text-wrap: balance;
  letter-spacing: -0.025em;
  line-height: 1.2;
}

p, li, blockquote {
  text-wrap: pretty;
}

/* Accessible Visually Hidden Utility (modern-web-guidance: accessibility) */
.visually-hidden:where(:not(:focus-within, :active)) {
  position: absolute !important;
  clip-path: inset(50%) !important;
  overflow: hidden !important;
  width: 1px !important;
  height: 1px !important;
  margin: -1px !important;
  padding: 0 !important;
  border: 0 !important;
  white-space: nowrap !important;
}

.skip-link {
  position: fixed;
  inset-block-start: 1rem;
  inset-inline-start: 1rem;
  z-index: 9999;
  padding: 0.75rem 1.25rem;
  background: var(--color-brand);
  color: #ffffff;
  font-weight: 600;
  border-radius: var(--radius-sm);
  text-decoration: none;
  box-shadow: var(--shadow-card);
}

/* High-contrast focus states */
:where(a:any-link, button, input, [tabindex="0"]):focus-visible {
  outline: 3px solid var(--color-brand);
  outline-offset: 3px;
}

/* 3. Ambient Background Blobs */
.ambient-bg {
  position: fixed;
  inset: 0;
  pointer-events: none;
  z-index: 0;
  overflow: clip;
}

.blob {
  position: absolute;
  border-radius: 50%;
  filter: blur(85px);
  opacity: 0.42;
  will-change: transform;
  animation: blob-float 18s ease-in-out infinite alternate;
}

.blob-1 {
  inline-size: 28rem;
  block-size: 28rem;
  background: radial-gradient(circle, #6366f1 0%, transparent 70%);
  inset-block-start: -8rem;
  inset-inline-start: -6rem;
}

.blob-2 {
  inline-size: 32rem;
  block-size: 32rem;
  background: radial-gradient(circle, #a855f7 0%, transparent 70%);
  inset-block-start: 20%;
  inset-inline-end: -10rem;
  animation-delay: -6s;
}

.blob-3 {
  inline-size: 26rem;
  block-size: 26rem;
  background: radial-gradient(circle, #ec4899 0%, transparent 70%);
  inset-block-end: -8rem;
  inset-inline-start: 25%;
  animation-delay: -12s;
}

@keyframes blob-float {
  0% {
    translate: 0 0;
    scale: 1;
  }
  100% {
    translate: 2rem 2.5rem;
    scale: 1.08;
  }
}

/* 4. Layout Containers & Glassmorphism Surfaces */
.container {
  inline-size: min(100% - 2.5rem, 74rem);
  margin-inline: auto;
  position: relative;
  z-index: 1;
}

.glass-card {
  background: var(--glass-bg);
  backdrop-filter: blur(18px) saturate(160%);
  -webkit-backdrop-filter: blur(18px) saturate(160%);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-card);
}

.glass-pill {
  background: var(--glass-bg-elevated);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid var(--control-border);
  border-radius: var(--radius-pill);
}

/* 5. Header */
.site-header {
  padding-block: 1.25rem;
}

.header-inner {
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.brand {
  display: flex;
  align-items: safe center;
  gap: 0.75rem;
}

.brand-logo {
  inline-size: 2.5rem;
  block-size: 2.5rem;
  border-radius: 0.75rem;
  background: linear-gradient(135deg, #4f46e5 0%, #9333ea 55%, #db2777 100%);
  color: #ffffff;
  display: grid;
  place-content: center;
  box-shadow: 0 8px 20px -4px rgba(99, 102, 241, 0.5);
}

.brand-logo svg {
  inline-size: 1.35rem;
  block-size: 1.35rem;
}

.brand-name {
  font-size: 1.25rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-primary);
}

.brand-accent {
  background: linear-gradient(135deg, var(--color-brand), var(--color-accent-pink));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
}

.privacy-pill {
  display: inline-flex;
  align-items: safe center;
  gap: 0.35rem;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 0.25rem 0.65rem;
  border-radius: var(--radius-pill);
  background: var(--success-bg);
  color: var(--success-text);
  border: 1px solid currentColor;
}

.privacy-pill svg {
  inline-size: 0.85rem;
  block-size: 0.85rem;
}

/* Theme Toggle Button */
.icon-btn {
  display: inline-flex;
  align-items: safe center;
  gap: 0.5rem;
  padding: 0.5rem 0.95rem;
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.875rem;
  font-weight: 600;
  cursor: pointer;
  transition: transform 0.2s ease, border-color 0.2s ease, background-color 0.2s ease;
}

.icon-btn:hover {
  transform: translateY(-1px);
  border-color: var(--color-brand);
}

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

.icon-btn svg {
  inline-size: 1.1rem;
  block-size: 1.1rem;
}

/* Show moon in light mode, sun in dark mode */
.icon-sun {
  display: none;
}
.icon-moon {
  display: block;
}

@media (prefers-color-scheme: dark) {
  html:not([data-theme="light"]) .icon-sun {
    display: block;
  }
  html:not([data-theme="light"]) .icon-moon {
    display: none;
  }
}

html[data-theme="dark"] .icon-sun {
  display: block;
}
html[data-theme="dark"] .icon-moon {
  display: none;
}

/* 6. Main & Hero Section */
.main-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 2rem;
  padding-block: 1rem 3.5rem;
}

.hero {
  text-align: center;
  max-inline-size: 46rem;
  margin-inline: auto;
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 0.85rem;
  padding-block: 0.5rem 0.25rem;
}

.hero-badge {
  display: inline-flex;
  align-items: safe center;
  gap: 0.5rem;
  padding: 0.35rem 0.9rem;
  border-radius: var(--radius-pill);
  font-size: 0.8125rem;
  font-weight: 600;
  background: var(--glass-bg-elevated);
  border: 1px solid var(--glass-border);
  color: var(--color-brand);
  box-shadow: 0 2px 10px rgba(79, 70, 229, 0.08);
}

.pulse-dot {
  inline-size: 0.5rem;
  block-size: 0.5rem;
  border-radius: 50%;
  background: var(--color-brand);
  box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.25);
}

.hero-title {
  font-size: clamp(2.15rem, 5vw, 3.35rem);
  font-weight: 800;
  background: linear-gradient(135deg, var(--text-primary) 20%, var(--color-brand) 65%, var(--color-accent-pink) 100%);
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  padding-bottom: 0.08em;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.175rem);
  color: var(--text-secondary);
  max-inline-size: 55ch;
}

/* 7. Workspace Grid (Drop Zone + Settings Panel) */
.workspace-grid {
  display: grid;
  grid-template-columns: 1.35fr 1fr;
  gap: 1.5rem;
  align-items: stretch;
}

@media (max-width: 900px) {
  .workspace-grid {
    grid-template-columns: 1fr;
  }
}

/* Drop Zone */
.dropzone-wrapper {
  padding: 1rem;
  display: flex;
}

.drop-zone {
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  text-align: center;
  gap: 0.9rem;
  padding: 2.5rem 1.75rem;
  border: 2.5px dashed var(--control-border);
  border-radius: calc(var(--radius-lg) - 0.35rem);
  background: rgba(99, 102, 241, 0.03);
  cursor: pointer;
  transition:
    border-color 0.25s ease,
    background-color 0.25s ease,
    transform 0.25s cubic-bezier(0.22, 1, 0.36, 1),
    box-shadow 0.25s ease;
  user-select: none;
}

.drop-zone:hover,
.drop-zone:focus-visible {
  border-color: var(--color-brand);
  background: rgba(99, 102, 241, 0.07);
}

.drop-zone.is-dragover {
  border-color: var(--color-brand);
  border-style: solid;
  background: rgba(99, 102, 241, 0.14);
  transform: scale(1.015);
  box-shadow: 0 0 0 6px rgba(99, 102, 241, 0.15);
}

.upload-icon-ring {
  inline-size: 4.5rem;
  block-size: 4.5rem;
  border-radius: 50%;
  display: grid;
  place-content: center;
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.15), rgba(219, 39, 119, 0.15));
  color: var(--color-brand);
  border: 1px solid var(--glass-border);
  transition: transform 0.3s cubic-bezier(0.34, 1.56, 0.64, 1), background-color 0.3s ease;
}

.drop-zone:hover .upload-icon-ring,
.drop-zone.is-dragover .upload-icon-ring {
  transform: translateY(-5px) scale(1.08);
}

.upload-svg {
  inline-size: 2.1rem;
  block-size: 2.1rem;
}

.dropzone-title {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.dropzone-subtitle {
  font-size: 0.9rem;
  color: var(--text-secondary);
  max-inline-size: 38ch;
}

.dropzone-cta {
  margin-block-start: 0.35rem;
}

.format-chips {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 0.4rem;
  margin-block-start: 0.4rem;
}

.chip {
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.04em;
  padding: 0.2rem 0.55rem;
  border-radius: 0.4rem;
  background: var(--glass-bg-elevated);
  border: 1px solid var(--glass-border);
  color: var(--text-muted);
}

/* 8. Buttons */
.btn {
  display: inline-flex;
  align-items: safe center;
  justify-content: center;
  gap: 0.5rem;
  font-family: inherit;
  font-size: 0.925rem;
  font-weight: 600;
  padding: 0.7rem 1.3rem;
  border-radius: var(--radius-sm);
  border: 1px solid transparent;
  cursor: pointer;
  text-decoration: none;
  transition:
    transform 0.18s ease,
    box-shadow 0.18s ease,
    background-color 0.18s ease,
    border-color 0.18s ease;
}

.btn svg {
  inline-size: 1.1rem;
  block-size: 1.1rem;
  flex-shrink: 0;
}

.btn:hover:not(:disabled) {
  transform: translateY(-1.5px);
}

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

.btn:disabled {
  opacity: 0.55;
  cursor: not-allowed;
}

.btn-primary {
  background: linear-gradient(135deg, #4f46e5 0%, #7c3aed 55%, #db2777 100%);
  color: #ffffff;
  box-shadow: 0 8px 20px -6px rgba(79, 70, 229, 0.55);
}

.btn-primary:hover:not(:disabled) {
  box-shadow: 0 12px 24px -6px rgba(79, 70, 229, 0.7);
}

.btn-secondary {
  background: var(--glass-bg-elevated);
  color: var(--text-primary);
  border-color: var(--control-border);
}

.btn-secondary:hover:not(:disabled) {
  border-color: var(--color-brand);
}

.btn-sm {
  padding: 0.5rem 0.9rem;
  font-size: 0.825rem;
}

.text-btn {
  background: none;
  border: none;
  color: var(--color-brand);
  font-family: inherit;
  font-size: 0.825rem;
  font-weight: 600;
  cursor: pointer;
  padding: 0.25rem 0.5rem;
  border-radius: 0.375rem;
  transition: background-color 0.15s ease;
}

.text-btn:hover {
  background: rgba(99, 102, 241, 0.1);
}

/* 9. Settings Panel & Brand-Consistent Form Controls */
.settings-panel {
  padding: 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

.panel-header {
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 0.75rem;
  padding-block-end: 0.85rem;
  border-block-end: 1px solid var(--glass-border);
}

.panel-title-group {
  display: flex;
  align-items: safe center;
  gap: 0.6rem;
}

.panel-title-group svg {
  inline-size: 1.25rem;
  block-size: 1.25rem;
  color: var(--color-brand);
}

.panel-title {
  font-size: 1.1rem;
  font-weight: 700;
}

.settings-form {
  display: flex;
  flex-direction: column;
  gap: 1.15rem;
}

.control-group {
  display: flex;
  flex-direction: column;
  gap: 0.45rem;
}

.control-group.is-disabled {
  opacity: 0.55;
}

.control-label-row {
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 0.5rem;
}

.control-label {
  font-size: 0.925rem;
  font-weight: 600;
  color: var(--text-primary);
}

.control-hint {
  font-size: 0.8rem;
  color: var(--text-secondary);
  line-height: 1.4;
}

.quality-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-inline-size: 3.4rem;
  padding: 0.2rem 0.6rem;
  border-radius: var(--radius-pill);
  font-size: 0.825rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  background: linear-gradient(135deg, rgba(79, 70, 229, 0.16), rgba(219, 39, 119, 0.16));
  color: var(--color-brand);
  border: 1px solid var(--glass-border);
}

/* Range Slider */
.slider-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.35rem;
  margin-block-start: 0.2rem;
}

input[type="range"] {
  inline-size: 100%;
  cursor: pointer;
  accent-color: var(--color-brand);
}

input[type="range"]:disabled {
  cursor: not-allowed;
}

.slider-ticks {
  display: flex;
  justify-content: space-between;
  font-size: 0.72rem;
  color: var(--text-muted);
}

/* Toggle Switch / Checkbox Cards */
.toggle-card {
  flex-direction: row;
  align-items: safe center;
  justify-content: space-between;
  gap: 1rem;
  padding: 0.85rem 1rem;
  border-radius: var(--radius-md);
  background: var(--glass-bg-elevated);
  border: 1px solid var(--glass-border);
}

.toggle-info {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.checkbox-label {
  display: inline-flex;
  align-items: safe center;
  gap: 0.65rem;
  cursor: pointer;
  position: relative;
  user-select: none;
}

.checkbox-visual {
  inline-size: 2.75rem;
  block-size: 1.55rem;
  border-radius: var(--radius-pill);
  background: rgba(148, 163, 184, 0.35);
  border: 1.5px solid var(--control-border);
  position: relative;
  flex-shrink: 0;
  transition: background-color 0.2s ease, border-color 0.2s ease;
}

.checkbox-visual::after {
  content: "";
  position: absolute;
  inset-block-start: 50%;
  inset-inline-start: 0.2rem;
  translate: 0 -50%;
  inline-size: 1.05rem;
  block-size: 1.05rem;
  border-radius: 50%;
  background: #ffffff;
  box-shadow: 0 2px 4px rgba(0, 0, 0, 0.25);
  transition: translate 0.2s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-visual {
  background: linear-gradient(135deg, #4f46e5, #db2777);
  border-color: transparent;
}

.checkbox-label input[type="checkbox"]:checked + .checkbox-visual::after {
  translate: 1.15rem -50%;
}

.checkbox-label input[type="checkbox"]:focus-visible + .checkbox-visual {
  outline: 3px solid var(--color-brand);
  outline-offset: 2px;
}

/* Fallback for older browsers without accent-color (modern-web-guidance: brand-consistent-forms) */
@supports not (accent-color: var(--color-brand)) {
  input[type="range"] {
    -webkit-appearance: none;
    appearance: none;
    background: transparent;
  }

  input[type="range"]::-webkit-slider-runnable-track {
    inline-size: 100%;
    block-size: 8px;
    background: linear-gradient(to right, var(--color-brand) var(--progress, 80%), #cbd5e1 var(--progress, 80%));
    border-radius: 4px;
  }

  input[type="range"]::-webkit-slider-thumb {
    -webkit-appearance: none;
    appearance: none;
    block-size: 18px;
    inline-size: 18px;
    border-radius: 50%;
    background: var(--color-brand);
    cursor: pointer;
    margin-top: -5px;
  }

  input[type="range"]::-moz-range-track {
    inline-size: 100%;
    block-size: 8px;
    background: #cbd5e1;
    border-radius: 4px;
  }

  input[type="range"]::-moz-range-thumb {
    block-size: 18px;
    inline-size: 18px;
    border-radius: 50%;
    background: var(--color-brand);
    cursor: pointer;
  }

  input[type="range"]::-moz-range-progress {
    background-color: var(--color-brand);
    block-size: 8px;
    border-radius: 4px;
  }
}

/* Resize Fieldset */
.resize-fieldset {
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  padding: 0.9rem 1rem;
  background: var(--glass-bg-elevated);
}

.resize-fieldset legend {
  padding-inline: 0.35rem;
}

.resize-mode-row {
  margin-block-top: 0.15rem;
}

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

.resize-dimensions {
  display: flex;
  align-items: flex-end;
  gap: 0.6rem;
  margin-block-start: 0.65rem;
  padding-block-start: 0.65rem;
  border-block-start: 1px dashed var(--glass-border);
  opacity: 1;
  translate: 0;
  transition:
    display 0.25s,
    opacity 0.25s ease-out,
    translate 0.25s ease-out;
  transition-behavior: allow-discrete;
}

@starting-style {
  .resize-dimensions {
    opacity: 0;
    translate: 0 -8px;
  }
}

.resize-dimensions:where([hidden]) {
  display: none;
  opacity: 0;
  translate: 0 -8px;
}

.dimension-field {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.3rem;
  min-inline-size: 0;
}

.dimension-label {
  font-size: 0.75rem;
  font-weight: 600;
  color: var(--text-secondary);
}

.dimension-divider {
  padding-block-end: 0.5rem;
  font-weight: 700;
  color: var(--text-muted);
}

.number-input {
  inline-size: 100%;
  padding: 0.5rem 0.65rem;
  border-radius: 0.5rem;
  border: 1.5px solid var(--control-border);
  background: var(--glass-bg);
  color: var(--text-primary);
  font-family: inherit;
  font-size: 0.875rem;
  font-variant-numeric: tabular-nums;
  transition: border-color 0.2s ease;
}

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

.number-input:focus {
  border-color: var(--color-brand);
}

/* 10. Animated Progress Indicator */
.progress-section {
  padding: 1.15rem 1.5rem;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  opacity: 1;
  translate: 0;
  transition:
    display 0.3s,
    opacity 0.3s ease-out,
    translate 0.3s ease-out;
  transition-behavior: allow-discrete;
}

@starting-style {
  .progress-section {
    opacity: 0;
    translate: 0 -10px;
  }
}

.progress-section:where([hidden]) {
  display: none;
  opacity: 0;
  translate: 0 -10px;
}

.progress-header {
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 1rem;
}

.progress-status {
  display: flex;
  align-items: safe center;
  gap: 0.65rem;
}

.spinner {
  inline-size: 1.1rem;
  block-size: 1.1rem;
  border: 2.5px solid rgba(99, 102, 241, 0.25);
  border-block-start-color: var(--color-brand);
  border-radius: 50%;
  animation: spin 0.75s linear infinite;
}

@keyframes spin {
  to {
    rotate: 360deg;
  }
}

.progress-text {
  font-size: 0.9rem;
  font-weight: 600;
  color: var(--text-primary);
}

.progress-count {
  font-size: 0.85rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--color-brand);
}

.progress-bar {
  inline-size: 100%;
  block-size: 0.6rem;
  border-radius: var(--radius-pill);
  overflow: clip;
  accent-color: var(--color-brand);
}

/* 11. Results Section & File Cards */
.results-section {
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
  opacity: 1;
  translate: 0;
  transition:
    display 0.35s,
    opacity 0.35s ease-out,
    translate 0.35s ease-out;
  transition-behavior: allow-discrete;
}

@starting-style {
  .results-section {
    opacity: 0;
    translate: 0 12px;
  }
}

.results-section:where([hidden]) {
  display: none;
  opacity: 0;
  translate: 0 12px;
}

.results-toolbar {
  padding: 1.15rem 1.5rem;
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 1rem;
  flex-wrap: wrap;
}

.results-summary {
  display: flex;
  flex-direction: column;
  gap: 0.2rem;
}

.results-title {
  font-size: 1.2rem;
  font-weight: 700;
  display: flex;
  align-items: safe center;
  gap: 0.6rem;
}

.count-badge {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 0.15rem 0.6rem;
  border-radius: var(--radius-pill);
  font-size: 0.8rem;
  font-weight: 700;
  background: var(--color-brand);
  color: #ffffff;
}

.savings-summary {
  font-size: 0.875rem;
  color: var(--text-secondary);
}

.results-actions {
  display: flex;
  align-items: safe center;
  gap: 0.75rem;
  flex-wrap: wrap;
}

.results-actions .btn[hidden] {
  display: none;
}

/* Cards Grid */
.cards-grid {
  list-style: none;
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(min(100%, 20rem), 1fr));
  gap: 1.25rem;
}

/* Individual File Card (modern-web-guidance: animate-element-entry-exit) */
.file-card {
  display: flex;
  flex-direction: column;
  overflow: clip;
  opacity: 1;
  translate: 0;
  scale: 1;
  transition:
    display 0.3s,
    opacity 0.3s ease-out,
    translate 0.3s ease-out,
    scale 0.3s ease-out,
    transform 0.22s ease,
    box-shadow 0.22s ease;
  transition-behavior: allow-discrete;
}

@starting-style {
  .file-card {
    opacity: 0;
    translate: 0 16px;
    scale: 0.97;
  }
}

.file-card:where(.is-removing, [hidden]) {
  display: none;
  opacity: 0;
  translate: 0 -12px;
  scale: 0.95;
}

.file-card:hover {
  transform: translateY(-3px);
}

/* Thumbnail Preview Container with Transparency Checkerboard */
.card-preview {
  position: relative;
  aspect-ratio: 16 / 10;
  inline-size: 100%;
  background-color: var(--checker-b);
  background-image:
    linear-gradient(45deg, var(--checker-a) 25%, transparent 25%),
    linear-gradient(-45deg, var(--checker-a) 25%, transparent 25%),
    linear-gradient(45deg, transparent 75%, var(--checker-a) 75%),
    linear-gradient(-45deg, transparent 75%, var(--checker-a) 75%);
  background-size: 16px 16px;
  background-position: 0 0, 0 8px, 8px -8px, -8px 0;
  display: grid;
  place-items: center;
  overflow: clip;
  border-block-end: 1px solid var(--glass-border);
}

.card-preview img {
  max-inline-size: 100%;
  max-block-size: 100%;
  inline-size: 100%;
  block-size: 100%;
  object-fit: contain;
  padding: 0.5rem;
  transition: transform 0.3s ease;
}

.file-card:hover .card-preview img {
  transform: scale(1.03);
}

.card-remove-btn {
  position: absolute;
  inset-block-start: 0.65rem;
  inset-inline-end: 0.65rem;
  inline-size: 2rem;
  block-size: 2rem;
  border-radius: 50%;
  border: 1px solid var(--glass-border);
  background: var(--glass-bg-elevated);
  color: var(--text-secondary);
  display: grid;
  place-content: center;
  cursor: pointer;
  transition: background-color 0.18s ease, color 0.18s ease, transform 0.18s ease;
}

.card-remove-btn:hover {
  background: var(--danger-bg);
  color: var(--danger-text);
  transform: scale(1.08);
}

.card-remove-btn svg {
  inline-size: 1rem;
  block-size: 1rem;
}

.card-format-tag {
  position: absolute;
  inset-block-start: 0.65rem;
  inset-inline-start: 0.65rem;
  padding: 0.2rem 0.55rem;
  border-radius: 0.4rem;
  font-size: 0.7rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  background: var(--glass-bg-elevated);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
}

/* Card Body */
.card-body {
  padding: 1.1rem 1.2rem 1.25rem;
  display: flex;
  flex-direction: column;
  gap: 0.85rem;
  flex: 1;
}

.card-title-row {
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-inline-size: 0;
}

.card-filename {
  font-size: 0.95rem;
  font-weight: 700;
  color: var(--text-primary);
  white-space: nowrap;
  overflow: clip;
  text-overflow: ellipsis;
}

.card-dimensions {
  font-size: 0.76rem;
  color: var(--text-muted);
  font-variant-numeric: tabular-nums;
}

/* Size Comparison Box */
.size-comparison {
  display: grid;
  grid-template-columns: 1fr auto 1fr;
  align-items: center;
  gap: 0.5rem;
  padding: 0.65rem 0.8rem;
  border-radius: var(--radius-sm);
  background: var(--glass-bg-elevated);
  border: 1px solid var(--glass-border);
}

.size-col {
  display: flex;
  flex-direction: column;
  gap: 0.1rem;
}

.size-col-end {
  text-align: end;
}

.size-label {
  font-size: 0.7rem;
  font-weight: 600;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: var(--text-muted);
}

.size-value {
  font-size: 0.88rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
  color: var(--text-primary);
}

.size-arrow {
  color: var(--text-muted);
  display: flex;
  align-items: center;
}

.size-arrow svg {
  inline-size: 1rem;
  block-size: 1rem;
}

/* Card Footer (Savings Badge + Download Button) */
.card-footer {
  display: flex;
  align-items: safe center;
  justify-content: space-between;
  gap: 0.75rem;
  margin-block-start: auto;
}

.savings-badge {
  display: inline-flex;
  align-items: safe center;
  gap: 0.3rem;
  padding: 0.3rem 0.65rem;
  border-radius: var(--radius-pill);
  font-size: 0.775rem;
  font-weight: 700;
  font-variant-numeric: tabular-nums;
}

.savings-badge.is-positive {
  background: var(--success-bg);
  color: var(--success-text);
}

.savings-badge.is-neutral {
  background: var(--warning-bg);
  color: var(--warning-text);
}

.savings-badge.is-converting {
  background: rgba(99, 102, 241, 0.14);
  color: var(--color-brand);
}

/* 12. Toast Notifications (modern-web-guidance: persistent-toast-notifications) */
.toast-container {
  position: fixed;
  inset-block-end: 1.5rem;
  inset-inline-end: 1.5rem;
  z-index: 9999;
  display: flex;
  flex-direction: column;
  gap: 0.65rem;
  inline-size: min(24rem, calc(100vw - 2rem));
  pointer-events: none;
}

.toast {
  /* Popover elements live in the Top Layer; position each fixed at bottom-right */
  position: fixed;
  inset: auto 1.5rem calc(1.5rem + var(--toast-offset, 0px)) auto;
  margin: 0;
  inline-size: min(24rem, calc(100vw - 2rem));
  pointer-events: auto;
  display: flex;
  align-items: flex-start;
  gap: 0.75rem;
  padding: 0.9rem 1rem;
  border-radius: var(--radius-md);
  background: var(--glass-bg-elevated);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid var(--control-border);
  box-shadow: var(--shadow-card);
  color: var(--text-primary);
  opacity: 1;
  translate: 0;
  transition:
    display 0.25s,
    overlay 0.25s,
    inset-block-end 0.25s ease-out,
    opacity 0.25s ease-out,
    translate 0.25s ease-out;
  transition-behavior: allow-discrete;
}

/* Progressive enhancement with CSS sibling-index() fallback where supported */
@supports (inset-block-end: calc(1.5rem * sibling-index())) {
  .toast {
    inset-block-end: calc(1.5rem + var(--toast-offset, calc((sibling-index() - 1) * 6.75rem)));
  }
}

@starting-style {
  .toast {
    opacity: 0;
    translate: 0 12px;
  }
}

.toast:where(.is-hiding, :not(:popover-open):where([popover])) {
  opacity: 0;
  translate: 0 12px;
}

.toast + .toast {
  margin-block-start: 0.15rem;
}

.toast.toast-error {
  border-inline-start: 4px solid var(--danger-text);
}

.toast.toast-success {
  border-inline-start: 4px solid var(--success-text);
}

.toast-icon {
  flex-shrink: 0;
  margin-block-start: 0.1rem;
}

.toast-error .toast-icon {
  color: var(--danger-text);
}

.toast-success .toast-icon {
  color: var(--success-text);
}

.toast-icon svg {
  inline-size: 1.2rem;
  block-size: 1.2rem;
}

.toast-content {
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: 0.15rem;
  min-inline-size: 0;
}

.toast-title {
  font-size: 0.875rem;
  font-weight: 700;
}

.toast-message {
  font-size: 0.8rem;
  color: var(--text-secondary);
  word-break: break-word;
}

.toast-close {
  background: none;
  border: none;
  color: var(--text-muted);
  cursor: pointer;
  padding: 0.2rem;
  border-radius: 0.35rem;
  display: grid;
  place-content: center;
}

.toast-close:hover {
  color: var(--text-primary);
  background: rgba(148, 163, 184, 0.15);
}

.toast-close svg {
  inline-size: 1rem;
  block-size: 1rem;
}

/* 13. Footer */
.site-footer {
  padding-block: 1.5rem;
  border-block-start: 1px solid var(--glass-border);
  margin-block-start: auto;
}

.footer-inner {
  display: flex;
  justify-content: center;
  text-align: center;
}

.footer-copy {
  display: inline-flex;
  align-items: safe center;
  gap: 0.45rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.footer-copy svg {
  inline-size: 1rem;
  block-size: 1rem;
  color: var(--color-brand);
}

/* 14. Responsive Adjustments & Reduced Motion (modern-web-guidance: accessibility) */
@media (max-width: 600px) {
  .container {
    inline-size: calc(100% - 1.5rem);
  }

  .drop-zone {
    padding: 1.75rem 1rem;
  }

  .results-toolbar {
    flex-direction: column;
    align-items: stretch;
  }

  .results-actions {
    inline-size: 100%;
  }

  .results-actions .btn {
    flex: 1;
  }
}

@media (prefers-reduced-motion: reduce) {
  *,
  *::before,
  *::after {
    animation-duration: 0.01ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.1s !important;
    scroll-behavior: auto !important;
  }

  .blob {
    animation: none !important;
  }

  .file-card,
  .resize-dimensions,
  .progress-section,
  .results-section,
  .toast {
    translate: none !important;
  }
}