/* YTDown — light-first, hairline-bordered interface with system fonts. */

/* ------------------------------------------------------------------ tokens */
:root {
  --paper: #FFFFFF;
  --card: #FFFFFF;
  --ink: #141A24;
  --ink-soft: #4E5A6B;
  --hairline: #DFE4EA;
  --cobalt: #C91F2C;
  --cobalt-hover: #A81924;
  --cobalt-button: #C91F2C;
  --cobalt-button-hover: #A81924;
  --cobalt-ink: #FFFFFF;
  --signal: #F2B705;
  --signal-ink: #141A24;
  --ok: #0F7A46;
  --danger: #B3261E;

  --font-display: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;

  --shell: 1180px;
  --space-1: .25rem;
  --space-2: .5rem;
  --space-3: .75rem;
  --space-4: 1rem;
  --space-5: 1.5rem;
  --space-6: 2rem;
  --space-7: 3rem;
  --space-8: 4.5rem;

  --r-sm: 6px;
  --r-md: 10px;

  color-scheme: light;
}

:root:not([data-theme="light"]) {
  @media (prefers-color-scheme: dark) {
    --paper: #101114;
    --card: #1C1F25;
    --ink: #F8F9FA;
    --ink-soft: #A8AFBA;
    --hairline: #30343B;
    --cobalt: #FF5A62;
    --cobalt-hover: #FF737A;
    --cobalt-button: #C91F2C;
    --cobalt-button-hover: #A81924;
    --cobalt-ink: #FFFFFF;
    --signal: #FF6B6B;
    --signal-ink: #141A24;
    --ok: #57D9A3;
    --danger: #FF9089;
    color-scheme: dark;
  }
}

:root[data-theme="dark"] {
  --paper: #101114;
  --card: #1C1F25;
  --ink: #F8F9FA;
  --ink-soft: #A8AFBA;
  --hairline: #30343B;
  --cobalt: #FF5A62;
  --cobalt-hover: #FF737A;
  --cobalt-button: #C91F2C;
  --cobalt-button-hover: #A81924;
  --cobalt-ink: #FFFFFF;
  --signal: #FF6B6B;
  --signal-ink: #141A24;
  --ok: #57D9A3;
  --danger: #FF9089;
  color-scheme: dark;
}

html[dir="rtl"] {
  --font-display: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-body: ui-sans-serif, system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
}

/* -------------------------------------------------------------------- base */
* , *::before, *::after { box-sizing: border-box; }
html { -webkit-text-size-adjust: 100%; scroll-behavior: smooth; }
body {
  margin: 0;
  background: var(--paper);
  color: var(--ink);
  font-family: var(--font-body);
  font-size: 16px;
  line-height: 1.55;
  -webkit-font-smoothing: antialiased;
}
h1, h2, h3 {
  font-family: var(--font-display);
  font-stretch: 118%;
  font-weight: 700;
  line-height: 1.15;
  margin: 0 0 var(--space-3);
  letter-spacing: -0.01em;
}
h1 { font-size: clamp(2rem, 1.6rem + 1.8vw, 3rem); }
h2 { font-size: clamp(1.5rem, 1.3rem + 1vw, 2.1rem); }
h3 { font-size: 1.15rem; }
p { margin: 0 0 var(--space-3); color: var(--ink-soft); }
a { color: var(--cobalt); }
[dir] a { text-underline-offset: 2px; }
img { max-width: 100%; display: block; }
[hidden] { display: none !important; }
button, input, select { font: inherit; color: inherit; }

/* ---------------------------------------------------------- accessibility */
.sr-only {
  position: absolute;
  width: 1px; height: 1px;
  padding: 0; margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}
.skip-link {
  position: absolute;
  inset-inline-start: var(--space-3);
  top: -3rem;
  background: var(--ink);
  color: var(--paper);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--r-sm);
  z-index: 200;
  transition: top .15s ease;
}
.skip-link:focus { top: var(--space-3); }

:focus-visible {
  outline: 3px solid var(--cobalt);
  outline-offset: 2px;
  border-radius: var(--r-sm);
}

@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: .001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: .001ms !important;
    scroll-behavior: auto !important;
  }
}

/* ---------------------------------------------------------------- layout */
.shell {
  max-width: var(--shell);
  margin-inline: auto;
  padding-inline: var(--space-5);
}
.shell.narrow { max-width: 760px; }
main { display: block; }

.section { padding-block: clamp(3.5rem, 7vw, 6rem); }
.section-alt { background: var(--card); border-block: 1px solid var(--hairline); }
.section-head { max-width: 700px; margin: 0 auto var(--space-6); text-align: center; }
.section-head h2 { margin-bottom: var(--space-2); }
.section-lede { max-width: 62ch; margin-inline: auto; font-size: 1.02rem; }

.prose p { color: var(--ink); max-width: 68ch; }

/* --------------------------------------------------------------- buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  min-height: 44px;
  padding: 0 var(--space-5);
  border-radius: var(--r-md);
  border: 1px solid transparent;
  font-family: var(--font-body);
  font-weight: 600;
  font-size: .95rem;
  cursor: pointer;
  text-decoration: none;
  background: transparent;
  transition: background-color .12s ease, border-color .12s ease, opacity .12s ease;
}
.btn:disabled { opacity: .5; cursor: not-allowed; }
.btn-primary { background: var(--cobalt-button); color: var(--cobalt-ink); }
.btn-primary:hover:not(:disabled) { background: var(--cobalt-button-hover); }
.btn-ghost { border-color: var(--hairline); color: var(--ink); background: var(--card); }
.btn-ghost:hover:not(:disabled) { border-color: var(--ink-soft); }
.btn-block { width: 100%; }
.link-btn {
  border: 0;
  background: none;
  color: var(--cobalt);
  font-weight: 600;
  padding: var(--space-1) 0;
  min-height: 44px;
  cursor: pointer;
}

/* ---------------------------------------------------------------- header */
.site-header {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--paper);
  border-block-end: 1px solid var(--hairline);
}
.header-inner {
  display: flex;
  align-items: center;
  gap: var(--space-5);
  min-height: 4rem;
  padding-block: var(--space-2);
}
.brand { display: flex; align-items: center; gap: var(--space-2); text-decoration: none; color: var(--ink); }
.brand-mark {
  display: grid;
  place-items: center;
  width: 34px; height: 34px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-sm);
  color: var(--cobalt);
  flex: none;
}
.brand-text { display: flex; flex-direction: column; line-height: 1.1; }
.brand-name { font-family: var(--font-display); font-stretch: 118%; font-weight: 700; font-size: 1.1rem; }
.brand-sub { font-size: .72rem; color: var(--ink-soft); }

.nav { display: flex; gap: var(--space-5); margin-inline-start: var(--space-4); }
.nav a { color: var(--ink-soft); text-decoration: none; font-weight: 600; font-size: .92rem; padding-block: var(--space-1); }
.nav a:hover, .nav a.is-active { color: var(--ink); }

.header-actions { display: flex; align-items: center; gap: var(--space-2); margin-inline-start: auto; }
.icon-btn {
  display: grid;
  place-items: center;
  width: 40px; height: 40px;
  border: 1px solid var(--hairline);
  border-radius: var(--r-sm);
  background: var(--card);
  color: var(--ink);
  cursor: pointer;
}
.icon-moon { display: none; }
[data-theme="dark"] .icon-sun { display: none; }
[data-theme="dark"] .icon-moon { display: block; }

.lang-switch { position: relative; }
.lang-toggle {
  display: flex; align-items: center; gap: var(--space-1);
  height: 40px; padding-inline: var(--space-3);
  border: 1px solid var(--hairline);
  border-radius: var(--r-sm);
  background: var(--card);
  color: var(--ink);
  cursor: pointer;
  font-size: .85rem;
  font-weight: 600;
}
.lang-menu {
  position: absolute;
  inset-inline-end: 0;
  top: calc(100% + var(--space-2));
  z-index: 50;
  background: var(--card);
  border: 1px solid var(--hairline);
  border-radius: var(--r-md);
  padding: var(--space-2);
  list-style: none;
  margin: 0;
  max-height: 60vh;
  overflow-y: auto;
  min-width: 180px;
  box-shadow: 0 8px 24px rgba(0,0,0,.12);
}
.lang-menu a {
  display: block;
  padding: var(--space-2) var(--space-3);
  border-radius: var(--r-sm);
  color: var(--ink);
  text-decoration: none;
  font-size: .9rem;
}
.lang-menu a:hover, .lang-menu a.is-active { background: var(--paper); }

.nav-toggle { display: none; }

/* ------------------------------------------------------------------ hero */
.hero {
  padding-block: clamp(3.25rem, 7vw, 6rem);
  background: var(--paper);
  color: var(--ink);
  border-block-end: 1px solid var(--hairline);
}
.hero-inner { display: grid; gap: var(--space-5); }
.hero-copy { max-width: 850px; text-align: center; margin-inline: auto; }
.hero h1 { margin-bottom: var(--space-3); color: var(--ink); font-size: clamp(2rem, 1.4rem + 2.3vw, 3.25rem); }
.hero .lede { max-width: 68ch; margin: 0 auto; color: var(--ink-soft); font-size: 1.05rem; }
.eyebrow { display: inline-block; margin-bottom: var(--space-2); color: var(--cobalt); font-size: .76rem; font-weight: 700; letter-spacing: .09em; text-transform: uppercase; }

/* ------------------------------------------------------------- tool panel */
.tool {
  width: min(100%, 980px);
  padding: clamp(1rem, 2.5vw, 1.5rem);
  background: var(--card);
  border: 1px solid var(--hairline);
  border-radius: 16px;
  transition: border-color .2s ease;
}
.tool[data-state="working"] { outline: 2px solid var(--signal); outline-offset: 4px; }
.tool[data-state="done"] { outline: 2px solid var(--ok); outline-offset: 4px; }

.tool-form { display: flex; flex-direction: column; gap: var(--space-3); }
.tool-label { position: absolute; width: 1px; height: 1px; overflow: hidden; clip: rect(0,0,0,0); white-space: nowrap; }
.tool-row { display: flex; gap: 8px; padding: 6px; background: var(--paper); border: 1px solid var(--hairline); border-radius: 11px; }
.tool-input {
  flex: 1;
  min-width: 0;
  height: 56px;
  padding-inline: var(--space-4);
  border: 0;
  border-radius: 7px;
  background: var(--paper);
  color: var(--ink);
  font-size: 1rem;
}
.tool-input:focus-visible { outline-offset: 0; }
.tool-paste { height: 48px; flex: none; border: 0; color: var(--cobalt); background: color-mix(in srgb, var(--cobalt) 8%, var(--paper)); }
.tool-submit { height: 48px; flex: none; font-size: 1rem; border-radius: 8px; }
.tool-note { max-width: 76ch; margin: 0 auto; color: var(--ink-soft); font-size: .85rem; text-align: center; }

.tool-error {
  margin-top: var(--space-4);
  padding: var(--space-3) var(--space-4);
  border: 1px solid var(--danger);
  border-inline-start-width: 4px;
  border-radius: var(--r-sm);
  background: color-mix(in srgb, var(--danger) 10%, var(--card));
  color: var(--ink);
  font-size: .92rem;
  display: flex;
  gap: var(--space-2);
  align-items: flex-start;
}
.tool-error svg { color: var(--danger); flex: none; margin-top: 2px; }
[data-state="idle"] .tool-error { display: none; }

.tool-stage { margin-top: var(--space-4); }
[data-state="idle"] .tool-stage { display: none; }
[data-state="loading"] .tool-form,
[data-state="preview-video"] .tool-form,
[data-state="preview-playlist"] .tool-form,
[data-state="working"] .tool-form,
[data-state="done"] .tool-form,
[data-state="loading"] .tool-error,
[data-state="preview-video"] .tool-error,
[data-state="preview-playlist"] .tool-error,
[data-state="working"] .tool-error,
[data-state="done"] .tool-error { display: none; }

/* skeleton (loading) */
.skeleton { display: flex; gap: var(--space-4); }
.skeleton-thumb { width: 160px; height: 90px; border-radius: var(--r-sm); background: var(--paper); flex: none; }
.skeleton-lines { flex: 1; display: flex; flex-direction: column; gap: var(--space-2); justify-content: center; }
.skeleton-line { display: block; height: 12px; border-radius: 6px; background: var(--paper); }
.skeleton-line.w-70 { width: 70%; }
.skeleton-line.w-50 { width: 50%; }
.skeleton-line.w-40 { width: 40%; }
.skeleton, .skeleton-thumb, .skeleton-line { position: relative; overflow: hidden; }
.skeleton-thumb::after, .skeleton-line::after {
  content: "";
  position: absolute; inset: 0;
  background: linear-gradient(90deg, transparent, color-mix(in srgb, var(--ink) 8%, transparent), transparent);
  animation: shimmer 1.4s ease-in-out infinite;
}
@keyframes shimmer { from { transform: translateX(-100%); } to { transform: translateX(100%); } }
@media (prefers-reduced-motion: reduce) { .skeleton-thumb::after, .skeleton-line::after { animation: none; } }
.stage-status { display: flex; align-items: center; gap: var(--space-2); margin: var(--space-4) 0 0; font-size: .92rem; }
.spinner {
  width: 16px; height: 16px;
  border: 2px solid var(--hairline);
  border-top-color: var(--cobalt);
  border-radius: 50%;
  animation: spin .8s linear infinite;
  flex: none;
}
@keyframes spin { to { transform: rotate(360deg); } }
@media (prefers-reduced-motion: reduce) { .spinner { animation: spin 1.6s linear infinite; } }

/* preview (video + playlist) */
.preview-head { display: flex; gap: var(--space-4); }
.preview-media { position: relative; flex: none; width: 160px; }
.preview-media img { width: 160px; height: 90px; object-fit: cover; border-radius: var(--r-sm); background: var(--paper); }
.preview-media .ph {
  width: 160px; height: 90px; border-radius: var(--r-sm);
  background: var(--paper); display: grid; place-items: center; color: var(--ink-soft);
}
.preview-duration {
  position: absolute;
  inset-inline-end: 6px; bottom: 6px;
  background: rgba(0,0,0,.72);
  color: #fff;
  font-size: .72rem;
  padding: 2px 6px;
  border-radius: 4px;
  font-variant-numeric: tabular-nums;
}
.preview-meta { min-width: 0; }
.preview-info { margin-top: var(--space-5); padding-top: var(--space-4); border-top: 1px solid var(--hairline); }
.badge {
  display: inline-block;
  font-size: .72rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: .04em;
  padding: 2px 8px;
  border-radius: 999px;
  border: 1px solid var(--hairline);
  color: var(--ink-soft);
  margin-bottom: var(--space-2);
}
.preview-title { margin: 0 0 var(--space-1); font-size: 1.05rem; overflow-wrap: anywhere; }
.preview-sub { margin: 0; font-size: .88rem; }
.link-btn.change-link { margin-block: var(--space-3); display: inline-block; }

.tabs { display: flex; gap: var(--space-2); border-block-end: 1px solid var(--hairline); margin-block: var(--space-4) var(--space-3); }
.tabs button {
  border: 0; background: none; cursor: pointer;
  padding: var(--space-2) var(--space-1);
  margin-block-end: -1px;
  border-block-end: 2px solid transparent;
  color: var(--ink-soft);
  font-weight: 600;
  min-height: 44px;
}
.tabs button[aria-selected="true"] { color: var(--ink); border-block-end-color: var(--cobalt); }

.quality-list { border: 0; margin: 0; padding: 0; display: flex; flex-direction: column; gap: var(--space-2); }
.quality-row {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3);
  border: 1px solid var(--hairline);
  border-radius: var(--r-sm);
  cursor: pointer;
}
.quality-row:has(input:checked) { border-color: var(--cobalt); background: color-mix(in srgb, var(--cobalt) 6%, var(--card)); }
.quality-row input { flex: none; width: 18px; height: 18px; accent-color: var(--cobalt); }
.quality-name { flex: 1; font-weight: 600; font-size: .92rem; display: flex; align-items: center; gap: var(--space-2); flex-wrap: wrap; }
.badge-recommended {
  font-size: .68rem; font-weight: 700; text-transform: uppercase; letter-spacing: .03em;
  color: var(--ok); border: 1px solid var(--ok); border-radius: 999px; padding: 1px 7px;
}
.quality-size { font-variant-numeric: tabular-nums; color: var(--ink-soft); font-size: .88rem; flex: none; }

.deletion-note { font-size: .82rem; margin: var(--space-3) 0 0; text-align: center; }

/* playlist */
.playlist-toolbar { display: flex; gap: var(--space-4); margin-block: var(--space-3); }
.entry-list {
  list-style: none; margin: 0 0 var(--space-4); padding: 0;
  max-height: 320px; overflow-y: auto;
  border: 1px solid var(--hairline); border-radius: var(--r-sm);
}
.entry-row { border-block-end: 1px solid var(--hairline); }
.entry-row:last-child { border-block-end: 0; }
.entry-row label {
  display: flex; align-items: center; gap: var(--space-3);
  padding: var(--space-2) var(--space-3);
  cursor: pointer;
  min-height: 44px;
}
.entry-row input { flex: none; width: 18px; height: 18px; accent-color: var(--cobalt); }
.entry-row img, .entry-row .ph { flex: none; width: 64px; height: 36px; object-fit: cover; border-radius: 4px; background: var(--paper); }
.entry-index { flex: none; width: 1.6em; color: var(--ink-soft); font-size: .82rem; font-variant-numeric: tabular-nums; }
.entry-title { flex: 1; min-width: 0; font-size: .88rem; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.entry-duration { flex: none; font-size: .8rem; color: var(--ink-soft); font-variant-numeric: tabular-nums; }
.selection-summary { font-size: .88rem; margin: var(--space-3) 0; font-variant-numeric: tabular-nums; }

/* working */
.working { text-align: center; padding-block: var(--space-2); }
.progress-track { height: 8px; border-radius: 999px; background: var(--paper); overflow: hidden; margin-bottom: var(--space-4); }
.progress-fill { height: 100%; background: var(--signal); border-radius: inherit; transition: width .4s ease; }
.progress-fill.is-indeterminate { animation: progress-indeterminate 1.6s ease-in-out infinite; }
@keyframes progress-indeterminate {
  from { transform: translateX(-110%); }
  to { transform: translateX(320%); }
}
@media (prefers-reduced-motion: reduce) {
  .progress-fill.is-indeterminate { animation: none; transform: none; }
}
.stage-list { list-style: none; margin: 0 0 var(--space-4); padding: 0; display: grid; gap: var(--space-2); text-align: start; }
.stage-list li { display: flex; align-items: center; gap: var(--space-2); color: var(--ink-soft); font-size: .9rem; }
.stage-list li.is-active { color: var(--ink); font-weight: 600; }
.stage-list li.is-active::before { content: ""; width: 8px; height: 8px; border-radius: 50%; background: var(--signal); flex: none; }
.stage-list li.is-done::before { content: "✓"; color: var(--ok); font-weight: 700; }
.stage-list li:not(.is-active):not(.is-done)::before { content: ""; width: 8px; height: 8px; border-radius: 50%; border: 1px solid var(--hairline); flex: none; }
.working-note { font-size: .85rem; margin-bottom: var(--space-4); }

/* done */
.done { text-align: center; padding-block: var(--space-2); }
.done-check {
  display: grid; place-items: center;
  width: 48px; height: 48px;
  margin: 0 auto var(--space-3);
  border-radius: 50%;
  border: 2px solid var(--ok);
  color: var(--ok);
}
.done h3 { margin-bottom: var(--space-4); }
.file-card {
  display: flex; align-items: center; gap: var(--space-3);
  border: 1px solid var(--hairline); border-radius: var(--r-sm);
  padding: var(--space-3); margin-bottom: var(--space-4);
  text-align: start;
}
.file-badge {
  flex: none;
  font-size: .72rem; font-weight: 700;
  border: 1px solid var(--hairline); border-radius: var(--r-sm);
  padding: var(--space-2);
}
.file-name { margin: 0; font-weight: 600; font-size: .9rem; overflow-wrap: anywhere; }
.file-size { margin: 0; font-size: .82rem; font-variant-numeric: tabular-nums; }
.done .btn { margin-bottom: var(--space-2); }

/* --------------------------------------------------------------- strip */
.strip { border-block: 1px solid var(--hairline); background: var(--card); }
.strip-inner {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  padding-block: var(--space-5);
}
.strip-item {
  padding-inline: var(--space-4);
  border-inline-start: 1px solid var(--hairline);
  display: flex; flex-direction: column; gap: var(--space-1);
}
.strip-item:first-child { border-inline-start: 0; }
.strip-item b { font-family: var(--font-display); font-stretch: 118%; font-size: 1.4rem; font-variant-numeric: tabular-nums; }
.strip-item span { color: var(--ink-soft); font-size: .82rem; }

/* ---------------------------------------------------------- homepage content */
.steps-grid, .features-grid, .format-grid { display: grid; grid-template-columns: repeat(3, minmax(0, 1fr)); gap: var(--space-4); }
.step-card, .feature-card, .format-card, .about-card { min-width: 0; padding: clamp(1.2rem, 2vw, 1.65rem); border: 1px solid var(--hairline); border-radius: 14px; background: var(--card); }
.step-card { position: relative; padding-top: 4.1rem; }
.step-icon { display: grid; place-items: center; width: 34px; height: 34px; margin-bottom: var(--space-3); border-radius: 9px; background: color-mix(in srgb, var(--cobalt) 9%, var(--card)); color: var(--cobalt); }
.step-icon svg { width: 19px; height: 19px; }
.step-number { position: absolute; inset-block-start: 1.1rem; inset-inline-start: 1.35rem; color: var(--cobalt); font-family: var(--font-display); font-weight: 700; font-size: .82rem; }
.step-card h3, .feature-card h3, .format-card h3 { margin-bottom: var(--space-2); font-size: 1.05rem; }
.step-card p, .feature-card p, .format-card p { margin: 0; font-size: .93rem; }
.features-grid { grid-template-columns: repeat(3, minmax(0, 1fr)); }
.feature-icon { display: grid; place-items: center; width: 42px; height: 42px; margin-bottom: var(--space-4); border-radius: 10px; background: color-mix(in srgb, var(--cobalt) 9%, var(--card)); color: var(--cobalt); }
.feature-icon svg { width: 22px; height: 22px; }
.format-tag { display: inline-flex; align-items: center; min-height: 30px; padding-inline: 10px; margin-bottom: var(--space-4); border-radius: 7px; background: color-mix(in srgb, var(--cobalt) 9%, var(--card)); color: var(--cobalt); font-size: .75rem; font-weight: 700; letter-spacing: .06em; }
.quality-table-wrap { overflow-x: auto; margin-top: var(--space-5); border: 1px solid var(--hairline); border-radius: 12px; background: var(--card); }
.quality-table { width: 100%; border-collapse: collapse; text-align: start; min-width: 520px; }
.quality-table caption { padding: var(--space-4); text-align: start; font-weight: 700; color: var(--ink); }
.quality-table th, .quality-table td { padding: .8rem 1rem; border-block-start: 1px solid var(--hairline); text-align: start; }
.quality-table th { color: var(--ink); font-size: .9rem; }
.quality-table td { color: var(--ink-soft); font-size: .9rem; }
.section-footnote { margin: var(--space-3) auto 0; max-width: 80ch; font-size: .85rem; text-align: center; }
.home-article-section { padding-block: clamp(2.5rem, 5vw, 4.25rem); background: var(--paper); border-block-end: 1px solid var(--hairline); }
.home-article-shell { max-width: 1040px; }
.home-article-card { padding: clamp(1.4rem, 3.5vw, 2.75rem); border: 1px solid var(--hairline); border-radius: 16px; background: var(--card); }
.home-article-header { max-width: 78ch; padding-bottom: var(--space-5); border-block-end: 1px solid var(--hairline); }
.home-article-header h2 { margin-bottom: var(--space-2); }
.home-article-deck { margin: 0; font-size: 1.05rem; }
.home-article-content { max-width: 76ch; padding-top: var(--space-4); }
.home-article-content h3 { margin: var(--space-5) 0 var(--space-2); font-size: 1.08rem; }
.home-article-content p, .home-article-content li { color: var(--ink-soft); }
.home-article-content ul, .home-article-content ol { padding-inline-start: 1.4em; }
.home-article-content li + li { margin-top: var(--space-2); }
.home-article-content figure { margin: var(--space-5) 0; }
.home-article-content figure img, .home-article-content > img { width: 100%; height: auto; border: 1px solid var(--hairline); border-radius: 12px; }
.home-article-content figcaption { margin-top: var(--space-2); color: var(--ink-soft); font-size: .85rem; }
.home-article-content blockquote { margin: var(--space-5) 0; padding: var(--space-3) var(--space-4); border-inline-start: 3px solid var(--cobalt); color: var(--ink); background: color-mix(in srgb, var(--cobalt) 5%, var(--card)); }
.home-article-content table { display: block; width: 100%; overflow-x: auto; border-collapse: collapse; }
.home-article-content th, .home-article-content td { padding: .7rem; border: 1px solid var(--hairline); text-align: start; }
.home-article-content pre { max-width: 100%; overflow-x: auto; padding: var(--space-4); border-radius: 10px; background: var(--paper); }
.home-article-content iframe, .home-article-content video { max-width: 100%; border-radius: 12px; }
.article-shell { max-width: 900px; }
.about-card { padding: clamp(1.5rem, 4vw, 3rem); }
.about-card h2 { margin-bottom: var(--space-4); }
.about-copy { columns: 2; column-gap: 2.5rem; }
.about-copy p { break-inside: avoid; color: var(--ink-soft); }
.text-link { display: inline-flex; align-items: center; gap: var(--space-2); margin-top: var(--space-2); color: var(--cobalt); font-weight: 700; text-decoration: none; }
.cta-section { padding-block: clamp(2.5rem, 5vw, 4rem); background: color-mix(in srgb, var(--cobalt) 6%, var(--card)); border-block: 1px solid var(--hairline); }
.cta-inner { display: flex; align-items: center; justify-content: space-between; gap: var(--space-5); }
.cta-inner h2 { margin-bottom: var(--space-2); }
.cta-inner p { margin: 0; }
.brand-mark { width: 36px; height: 36px; overflow: hidden; border: 0; border-radius: 9px; }
.brand-mark img { width: 100%; height: 100%; }

/* ------------------------------------------------------------------ FAQ */
.faq-list { overflow: hidden; border: 1px solid var(--hairline); border-radius: 14px; background: var(--card); }
.faq-item { padding-inline: var(--space-4); border-block-end: 1px solid var(--hairline); }
.faq-item:last-child { border-block-end: 0; }
.faq-item summary {
  cursor: pointer;
  list-style: none;
  padding: var(--space-4) 0;
  font-weight: 600;
  display: flex; justify-content: space-between; align-items: center; gap: var(--space-3);
  min-height: 44px;
}
.faq-item summary::-webkit-details-marker { display: none; }
.faq-item summary::after {
  content: "+";
  font-family: var(--font-display);
  font-size: 1.2rem;
  color: var(--ink-soft);
  flex: none;
}
.faq-item[open] summary::after { content: "–"; }
.faq-item p { padding-bottom: var(--space-4); margin: 0; max-width: 70ch; }

/* ---------------------------------------------------------------- footer */
.site-footer { border-block-start: 1px solid var(--hairline); padding-block: var(--space-7) var(--space-5); background: var(--card); }
.footer-grid { display: grid; grid-template-columns: minmax(230px, 1.6fr) repeat(3, minmax(120px, 1fr)); gap: var(--space-6); margin-bottom: var(--space-6); }
.footer-brand p { font-size: .88rem; max-width: 34ch; margin-top: var(--space-3); }
.footer-col h3 { font-size: .82rem; text-transform: uppercase; letter-spacing: .03em; color: var(--ink-soft); margin-bottom: var(--space-3); }
.footer-col ul { list-style: none; margin: 0; padding: 0; display: grid; gap: var(--space-2); }
.footer-col a { color: var(--ink); text-decoration: none; font-size: .9rem; }
.footer-col a:hover { color: var(--cobalt); }
.footer-bottom { border-block-start: 1px solid var(--hairline); padding-top: var(--space-4); display: flex; flex-wrap: wrap; gap: var(--space-2) var(--space-5); }
.footer-bottom p { margin: 0; font-size: .8rem; }

/* --------------------------------------------------------- content pages */
.page-hero { padding-block: var(--space-7) var(--space-5); }
.article { padding-bottom: var(--space-8); }
.article-card h2 { margin-top: var(--space-6); }
.article-card ul { color: var(--ink-soft); padding-inline-start: 1.2em; }
.article-card li { margin-bottom: var(--space-2); }
.callout {
  border: 1px solid var(--hairline);
  border-inline-start: 4px solid var(--cobalt);
  border-radius: var(--r-sm);
  padding: var(--space-4);
  background: var(--card);
  margin-block: var(--space-5);
}
.callout p { margin: 0; color: var(--ink); }
.contact-card { display: flex; align-items: center; gap: var(--space-4); border: 1px solid var(--hairline); border-radius: var(--r-md); padding: var(--space-5); margin-block: var(--space-5); }
.icon-tile { display: grid; place-items: center; width: 44px; height: 44px; border: 1px solid var(--hairline); border-radius: var(--r-sm); color: var(--cobalt); flex: none; }
.contact-email { font-weight: 600; font-size: 1.05rem; }
.updated { font-size: .82rem; color: var(--ink-soft); }
.back-link { display: inline-flex; align-items: center; gap: var(--space-2); text-decoration: none; color: var(--ink); font-weight: 600; margin-top: var(--space-5); }

/* ---------------------------------------------------------------- 900px */
@media (max-width: 900px) {
  .nav { display: none; }
  .nav-toggle { display: grid; }
  .site-header.nav-open .nav {
    display: flex;
    flex-direction: column;
    position: absolute;
    inset-inline: 0;
    top: 100%;
    background: var(--paper);
    border-block-end: 1px solid var(--hairline);
    padding: var(--space-4) var(--space-5);
    gap: var(--space-3);
  }
  .footer-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
  .steps-grid, .format-grid, .features-grid { grid-template-columns: repeat(2, minmax(0, 1fr)); }
}

/* ---------------------------------------------------------------- 720px */
@media (max-width: 720px) {
  .shell { padding-inline: 20px; }
  .section { padding-block: 2.75rem; }
  .strip-inner { grid-template-columns: repeat(2, minmax(0, 1fr)); row-gap: var(--space-4); padding-block: var(--space-4); }
  .strip-item { min-width: 0; padding-inline: var(--space-3); }
  .strip-item:nth-child(3) { border-inline-start: 0; }
  .preview-head, .skeleton { flex-direction: column; }
  .preview-media, .preview-media img, .preview-media .ph, .skeleton-thumb { width: 100%; height: auto; aspect-ratio: 16/9; }
  .about-copy { columns: 1; }
  .contact-card { align-items: flex-start; flex-wrap: wrap; }
  .contact-email { overflow-wrap: anywhere; }
  .quality-size { max-width: 34%; text-align: end; white-space: normal; overflow-wrap: anywhere; }
}

/* ---------------------------------------------------------------- 520px */
@media (max-width: 520px) {
  .shell { padding-inline: 16px; }
  .footer-grid, .steps-grid, .format-grid, .features-grid { grid-template-columns: 1fr; }
  .footer-grid { gap: var(--space-5); }
  .cta-inner { align-items: stretch; flex-direction: column; }
  .cta-inner .btn { width: 100%; }
  .hero { padding-block: 2.5rem; }
  .hero-inner { gap: var(--space-4); }
  .hero-copy { text-align: start; }
  .hero h1 { font-size: clamp(1.8rem, 8vw, 2.35rem); }
  .hero .lede { font-size: .95rem; }
  .tool { padding: 12px; border-radius: 12px; }
  .tool-row { display: grid; grid-template-columns: repeat(2, minmax(0, 1fr)); gap: 7px; padding: 5px; }
  .tool-input { grid-column: 1 / -1; width: 100%; height: 50px; padding-inline: 12px; font-size: 16px; }
  .tool-paste, .tool-submit { width: 100%; min-width: 0; height: 46px; padding-inline: 8px; font-size: .9rem; }
  .tool-note { text-align: start; font-size: .82rem; }
  .header-inner { min-height: 3.75rem; gap: 8px; padding-inline: 12px; }
  .brand { gap: 7px; }
  .brand-mark { width: 34px; height: 34px; }
  .brand-name { font-size: 1rem; }
  .brand-sub, .lang-toggle-label { display: none; }
  .header-actions { gap: 6px; }
  .icon-btn { width: 42px; height: 42px; min-height: 42px; padding: 0; display: grid; place-items: center; }
  .lang-toggle { width: 42px; height: 42px; min-height: 42px; padding: 0; justify-content: center; gap: 2px; }
  .site-header.nav-open .nav { padding: 8px 16px 14px; gap: 2px; box-shadow: 0 10px 20px rgba(0,0,0,.08); }
  .site-header.nav-open .nav a { display: flex; align-items: center; min-height: 46px; padding-inline: 8px; }
  .section-head { margin-bottom: var(--space-5); text-align: start; }
  .section-lede { margin-inline: 0; font-size: .95rem; }
  .home-article-card, .about-card { padding: 18px; border-radius: 12px; }
  .home-article-deck { font-size: .98rem; }
  .feature-card, .format-card, .step-card { padding: 18px; }
  .step-card { padding-top: 3.75rem; }
  .quality-table caption, .quality-table th, .quality-table td { padding: 10px 12px; }
  .preview-head { gap: 12px; }
  .preview-media { max-width: 100%; }
  .preview-title { font-size: 1rem; }
  .quality-row { flex-wrap: wrap; }
  .quality-name { min-width: 0; }
  .quality-size { margin-inline-start: auto; }
  .playlist-toolbar { flex-wrap: wrap; gap: 8px; }
  .entry-row label { gap: 8px; padding-inline: 8px; }
  .entry-row img, .entry-row .ph { width: 56px; height: 32px; }
  .entry-title { font-size: .82rem; }
  .entry-duration { font-size: .74rem; }
  .footer-bottom { flex-direction: column; gap: 8px; }
}

/* ------------------------------------------------------------------ print */
@media print {
  .site-header, .site-footer, .skip-link, .tool-paste, .theme-toggle, .lang-switch, .nav-toggle { display: none !important; }
  body { background: #fff; color: #111; }
  a { color: #111; text-decoration: underline; }
}