/* ── Theme ──────────────────────────────────────────────────────── */
:root {
  --primary:    #06b6d4;
  --secondary:  #0891b2;
  --grad:       linear-gradient(135deg,#06b6d4,#0891b2);
  --bg:         #0f0f14;
  --bg-card:    #1e1e28;
  --bg-surface: #18181f;
  --text:       #e8e8f0;
  --text-muted: #a0a0b8;
  --text-faint: #636380;
  --border:          rgba(255,255,255,.07);
  --border-medium:   rgba(255,255,255,.12);
  --radius:    14px;
  --radius-sm:  8px;
  --font: 'Inter', system-ui, -apple-system, sans-serif;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; scroll-behavior: smooth; }
body { background: var(--bg); color: var(--text); font-family: var(--font); line-height: 1.7; }
a { color: var(--primary); text-decoration: none; }
a:hover { text-decoration: underline; }
code { background: rgba(255,255,255,.07); border-radius: 4px; padding: 1px 5px; font-size: .88em; font-family: 'JetBrains Mono','Fira Code',monospace; color: #70d8f0; }
img { display: block; max-width: 100%; }
button { cursor: pointer; border: none; font-family: inherit; }

/* ── Header ─────────────────────────────────────────────────────── */
.site-header {
  background: rgba(15,15,20,.92);
  backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  position: sticky; top: 0; z-index: 100;
}
.header-inner {
  max-width: 1140px; margin: 0 auto; padding: 0 20px;
  height: 62px; display: flex; align-items: center; justify-content: space-between; gap: 20px;
}
.logo { display: flex; align-items: center; gap: 9px; text-decoration: none; }
.logo-icon { width: 32px; height: 32px; flex-shrink: 0; }
.logo-text { font-size: 1.05rem; font-weight: 700; color: var(--text); }
.main-nav { display: flex; align-items: center; gap: 4px; }
.nav-link { padding: 6px 12px; border-radius: var(--radius-sm); font-size: .88rem; font-weight: 500; color: var(--text-muted); transition: color .15s, background .15s; }
.nav-link:hover, .nav-link.active { color: var(--text); background: rgba(255,255,255,.06); }

/* ── Layout ──────────────────────────────────────────────────────── */
.main-wrap {
  max-width: 1140px; margin: 0 auto; padding: 28px 20px 80px;
}
.ad-slot {
  background: var(--bg-surface); border: 1px dashed var(--border-medium);
  border-radius: var(--radius-sm); min-height: 90px;
  display: flex; align-items: center; justify-content: center;
  margin: 18px 0; color: var(--text-faint); font-size: .78rem;
}

/* ── Hero ────────────────────────────────────────────────────────── */
.tool-hero { text-align: center; padding: 20px 0 28px; }
.tool-badge {
  display: inline-flex; align-items: center; gap: 6px;
  padding: 5px 13px; border-radius: 20px;
  background: rgba(6,182,212,.12); color: var(--primary);
  font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .08em;
  margin-bottom: 14px;
}
.tool-title { font-size: clamp(1.8rem,4vw,2.6rem); font-weight: 800; line-height: 1.2; margin-bottom: 12px; }
.gradient-title {
  background: var(--grad);
  -webkit-background-clip: text; background-clip: text; -webkit-text-fill-color: transparent;
}
.tool-subtitle { font-size: 1rem; color: var(--text-muted); max-width: 620px; margin: 0 auto; }

/* ── Upload pair ─────────────────────────────────────────────────── */
.upload-pair {
  display: grid; grid-template-columns: 1fr 1fr; gap: 14px; margin-bottom: 10px;
}
@media (max-width: 600px) { .upload-pair { grid-template-columns: 1fr; } }

.upload-zone {
  border: 2px dashed var(--border-medium);
  border-radius: var(--radius); padding: 28px 20px;
  text-align: center; cursor: pointer;
  transition: border-color .2s, background .2s;
  background: var(--bg-surface);
  position: relative;
}
.upload-zone:hover, .upload-zone.drag-over {
  border-color: var(--primary); background: rgba(6,182,212,.04);
}
.upload-zone-label {
  font-size: .68rem; font-weight: 800; text-transform: uppercase; letter-spacing: .1em;
  color: var(--primary); margin-bottom: 10px;
}
.upload-icon {
  width: 44px; height: 44px; margin: 0 auto 12px;
  background: rgba(6,182,212,.12); border-radius: 12px;
  display: flex; align-items: center; justify-content: center;
}
.upload-icon svg { width: 22px; height: 22px; color: var(--primary); }
.upload-title { font-size: .95rem; font-weight: 600; color: var(--text); margin-bottom: 5px; }
.upload-sub  { font-size: .78rem; color: var(--text-faint); margin-bottom: 14px; }
.btn-upload {
  display: inline-block; padding: 8px 18px;
  background: var(--grad); color: #fff; border-radius: var(--radius-sm);
  font-size: .84rem; font-weight: 600; cursor: pointer; border: none;
  transition: opacity .15s;
}
.btn-upload:hover { opacity: .88; }

/* Thumbnail inside upload zone when image loaded */
.loaded-zone { padding: 0; overflow: hidden; position: relative; cursor: default; }
.loaded-zone .zone-thumb {
  width: 100%; aspect-ratio: 4/3; object-fit: contain;
  background: #0a0a10; border-radius: calc(var(--radius) - 2px);
}
.loaded-zone .zone-footer {
  padding: 10px 14px; display: flex; align-items: center; gap: 8px;
  border-top: 1px solid var(--border);
}
.zone-label-badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 22px; height: 22px; border-radius: 50%;
  background: var(--grad); color: #fff; font-size: .72rem; font-weight: 800;
  flex-shrink: 0;
}
.zone-filename { font-size: .82rem; color: var(--text-muted); flex: 1; min-width: 0; overflow: hidden; text-overflow: ellipsis; white-space: nowrap; }
.zone-dims     { font-size: .74rem; color: var(--text-faint); flex-shrink: 0; }
.zone-change   {
  background: none; border: 1px solid var(--border-medium);
  border-radius: 6px; padding: 3px 8px; font-size: .72rem; color: var(--text-muted);
  transition: border-color .15s, color .15s;
}
.zone-change:hover { border-color: var(--primary); color: var(--primary); }

/* Swap button */
.swap-row { text-align: center; margin: 0 0 20px; }
.btn-swap {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 8px 18px; border: 1px solid var(--border-medium);
  border-radius: var(--radius-sm); background: none;
  font-size: .85rem; font-weight: 600; color: var(--text-muted);
  transition: border-color .15s, color .15s;
}
.btn-swap:hover { border-color: var(--primary); color: var(--primary); }

/* ── Mode tabs ───────────────────────────────────────────────────── */
.mode-tabs {
  display: flex; gap: 6px; flex-wrap: wrap; margin-bottom: 16px;
}
.mode-tab {
  display: flex; align-items: center; gap: 6px;
  padding: 7px 16px; border-radius: var(--radius-sm);
  font-size: .84rem; font-weight: 600; color: var(--text-muted);
  background: var(--bg-card); border: 1px solid var(--border);
  transition: all .15s;
}
.mode-tab:hover { color: var(--text); border-color: var(--border-medium); }
.mode-tab.active { background: rgba(6,182,212,.14); color: var(--primary); border-color: rgba(6,182,212,.35); }
.mode-tab svg { width: 14px; height: 14px; flex-shrink: 0; }

/* ── Compare container ───────────────────────────────────────────── */
.compare-container {
  width: 100%; height: 500px;
  position: relative; overflow: hidden;
  background: #090910; border-radius: var(--radius);
  border: 1px solid var(--border);
  user-select: none; touch-action: none;
}
.compare-container.cursor-slider { cursor: col-resize; }
.compare-container.cursor-default { cursor: default; }

/* Both images fill the container */
.cmp-img {
  position: absolute; inset: 0;
  width: 100%; height: 100%; object-fit: contain;
  pointer-events: none;
}

/* Slider label badges */
.cmp-label {
  position: absolute; top: 12px;
  width: 28px; height: 28px; border-radius: 50%;
  background: rgba(0,0,0,.55); backdrop-filter: blur(4px);
  display: flex; align-items: center; justify-content: center;
  font-size: .72rem; font-weight: 800; color: #fff;
  pointer-events: none; z-index: 10;
}
.cmp-label-a { left: 12px; }
.cmp-label-b { right: 12px; }

/* ── Slider mode ─────────────────────────────────────────────────── */
.cmp-img-b-clip {
  position: absolute; inset: 0;
  pointer-events: none;
  /* width is NOT set dynamically — clip-path handles the reveal */
}
.cmp-img-b-clip img {
  position: absolute; left: 0; top: 0;
  width: 100%; height: 100%; object-fit: contain;
}

.cmp-divider {
  position: absolute; top: 0; bottom: 0; width: 3px;
  background: #fff;
  box-shadow: 0 0 8px rgba(0,0,0,.6);
  transform: translateX(-50%);
  z-index: 10; pointer-events: none;
}
.cmp-handle {
  position: absolute; top: 50%; left: 50%;
  transform: translate(-50%, -50%);
  width: 40px; height: 40px; border-radius: 50%;
  background: #fff; box-shadow: 0 2px 10px rgba(0,0,0,.4);
  display: flex; align-items: center; justify-content: center;
  color: #333; pointer-events: all; cursor: col-resize;
}
.cmp-handle svg { width: 18px; height: 18px; }

/* ── Side by side mode ───────────────────────────────────────────── */
.cmp-sbs {
  display: flex; width: 100%; height: 100%;
}
.cmp-sbs-panel {
  flex: 1; overflow: hidden; position: relative;
  display: flex; align-items: center; justify-content: center;
}
.cmp-sbs-panel + .cmp-sbs-panel {
  border-left: 2px solid rgba(255,255,255,.15);
}
.cmp-sbs-img {
  width: 100%; height: 100%; object-fit: contain;
}
.cmp-sbs-badge {
  position: absolute; bottom: 10px; left: 50%; transform: translateX(-50%);
  padding: 3px 10px; border-radius: 10px;
  background: rgba(0,0,0,.55); backdrop-filter: blur(4px);
  font-size: .72rem; font-weight: 700; color: #fff;
}

/* ── Overlay mode ────────────────────────────────────────────────── */
.cmp-overlay { position: relative; width: 100%; height: 100%; }
.cmp-overlay-img {
  position: absolute; inset: 0;
  width: 100%; height: 100%; object-fit: contain;
}
.cmp-overlay-slider {
  position: absolute; bottom: 16px; left: 50%; transform: translateX(-50%);
  background: rgba(0,0,0,.6); backdrop-filter: blur(6px);
  border-radius: 30px; padding: 10px 18px;
  display: flex; align-items: center; gap: 12px;
  z-index: 10;
}
.cmp-overlay-slider span { font-size: .75rem; font-weight: 700; color: #fff; width: 16px; text-align: center; }
.overlay-range {
  -webkit-appearance: none; appearance: none;
  width: 180px; height: 4px; border-radius: 2px;
  background: rgba(255,255,255,.3); outline: none; cursor: pointer;
}
.overlay-range::-webkit-slider-thumb {
  -webkit-appearance: none; appearance: none;
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--primary); cursor: pointer;
  box-shadow: 0 1px 4px rgba(0,0,0,.3);
}
.overlay-range::-moz-range-thumb {
  width: 18px; height: 18px; border-radius: 50%;
  background: var(--primary); cursor: pointer; border: none;
}

/* ── Diff mode ───────────────────────────────────────────────────── */
.cmp-diff { position: relative; width: 100%; height: 100%; }
.cmp-diff-img {
  position: absolute; inset: 0;
  width: 100%; height: 100%; object-fit: contain;
}
.cmp-diff-loading {
  position: absolute; inset: 0; display: flex; flex-direction: column;
  align-items: center; justify-content: center; gap: 12px;
  color: var(--text-muted); font-size: .9rem;
}

/* ── Diff stats ──────────────────────────────────────────────────── */
.diff-stats {
  display: grid; grid-template-columns: repeat(auto-fit, minmax(140px, 1fr));
  gap: 10px; margin-top: 14px;
}
.diff-stat-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 14px 16px; text-align: center;
}
.diff-stat-val { font-size: 1.6rem; font-weight: 800; color: var(--primary); line-height: 1.1; }
.diff-stat-lbl { font-size: .73rem; color: var(--text-faint); margin-top: 3px; }
.diff-legend {
  display: flex; align-items: center; gap: 20px; flex-wrap: wrap;
  margin-top: 10px; padding: 10px 14px;
  background: var(--bg-card); border-radius: var(--radius-sm);
  font-size: .78rem; color: var(--text-muted);
}
.diff-legend-dot { width: 12px; height: 12px; border-radius: 50%; flex-shrink: 0; }

/* ── Diff download btn ───────────────────────────────────────────── */
.btn-download-diff {
  display: inline-flex; align-items: center; gap: 7px;
  padding: 8px 18px; background: var(--grad); color: #fff;
  border-radius: var(--radius-sm); font-size: .85rem; font-weight: 600;
  transition: opacity .15s; margin-top: 12px;
}
.btn-download-diff:hover { opacity: .87; }
.btn-download-diff svg { width: 14px; height: 14px; }

/* ── Image info bar ──────────────────────────────────────────────── */
.img-info-bar {
  display: grid; grid-template-columns: 1fr auto 1fr; gap: 10px;
  margin-top: 14px; align-items: start;
}
@media (max-width: 580px) { .img-info-bar { grid-template-columns: 1fr 1fr; } }
.img-info-bar .sep { border-left: 1px solid var(--border); height: 40px; margin: auto; }
@media (max-width: 580px) { .img-info-bar .sep { display: none; } }
.img-info-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius-sm); padding: 10px 14px;
  display: flex; flex-direction: column; gap: 2px;
}
.img-info-card .badge {
  display: inline-flex; align-items: center; justify-content: center;
  width: 20px; height: 20px; border-radius: 50%;
  background: var(--grad); color: #fff; font-size: .68rem; font-weight: 800;
  margin-bottom: 4px;
}
.img-info-name { font-size: .82rem; color: var(--text); font-weight: 500; word-break: break-all; }
.img-info-meta { font-size: .75rem; color: var(--text-faint); }

/* ── Spinner ─────────────────────────────────────────────────────── */
.spinner {
  width: 36px; height: 36px; border-radius: 50%;
  border: 3px solid rgba(6,182,212,.2);
  border-top-color: var(--primary);
  animation: spin .8s linear infinite;
}
@keyframes spin { to { transform: rotate(360deg); } }

/* ── Sections ────────────────────────────────────────────────────── */
.page-section { max-width: 100%; }
.section-head { text-align: center; margin-bottom: 28px; }
.section-title { font-size: clamp(1.2rem,2.5vw,1.55rem); font-weight: 700; color: #fff; margin-bottom: 8px; }
.section-desc  { font-size: .92rem; color: var(--text-muted); max-width: 600px; margin: 0 auto; }
.section-divider { border: none; border-top: 1px solid var(--border); margin: 40px 0; }

/* ── Feature grid ────────────────────────────────────────────────── */
.features-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(250px, 1fr)); gap: 14px;
}
.feature-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px;
}
.feature-icon { font-size: 1.6rem; margin-bottom: 10px; }
.feature-title { font-size: .95rem; font-weight: 700; color: #fff; margin-bottom: 6px; }
.feature-desc  { font-size: .83rem; color: var(--text-muted); line-height: 1.6; }

/* ── Steps ───────────────────────────────────────────────────────── */
.steps-grid { display: flex; flex-direction: column; gap: 14px; }
.step-card {
  display: flex; align-items: flex-start; gap: 16px;
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px 20px;
}
.step-number {
  width: 34px; height: 34px; border-radius: 50%;
  background: var(--grad); color: #fff;
  display: flex; align-items: center; justify-content: center;
  font-size: .88rem; font-weight: 800; flex-shrink: 0;
}
.step-title { font-size: .95rem; font-weight: 700; color: #fff; margin-bottom: 4px; }
.step-desc  { font-size: .84rem; color: var(--text-muted); }

/* ── Logic grid ──────────────────────────────────────────────────── */
.logic-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(300px, 1fr)); gap: 14px;
}
.logic-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 20px;
  border-left: 3px solid var(--primary);
}
.logic-title { font-size: .9rem; font-weight: 700; color: var(--primary); margin-bottom: 8px; }
.logic-desc  { font-size: .83rem; color: var(--text-muted); line-height: 1.65; }

/* ── FAQ ─────────────────────────────────────────────────────────── */
.faq-list { display: flex; flex-direction: column; gap: 8px; }
.faq-item { background: var(--bg-card); border: 1px solid var(--border); border-radius: var(--radius-sm); overflow: hidden; }
.faq-q {
  width: 100%; padding: 15px 18px; background: none; color: var(--text);
  font-size: .92rem; font-weight: 600; text-align: left;
  display: flex; justify-content: space-between; align-items: center; gap: 12px;
  transition: background .15s;
}
.faq-q:hover { background: rgba(255,255,255,.03); }
.faq-icon { font-size: 1.1rem; color: var(--primary); flex-shrink: 0; transition: transform .2s; }
.faq-a { max-height: 0; overflow: hidden; transition: max-height .3s ease; }
.faq-a p { padding: 0 18px 16px; font-size: .88rem; color: var(--text-muted); line-height: 1.7; }
.faq-item.open .faq-a  { max-height: 600px; }
.faq-item.open .faq-icon { transform: rotate(45deg); }

/* ── Related grids ───────────────────────────────────────────────── */
.related-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px;
}
.related-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px; display: flex; flex-direction: column; gap: 8px;
  transition: border-color .15s;
}
.related-card:hover { border-color: var(--primary); text-decoration: none; }
.related-icon {
  width: 40px; height: 40px; border-radius: 10px;
  display: flex; align-items: center; justify-content: center;
}
.related-icon svg { width: 18px; height: 18px; color: #fff; }
.related-name { font-size: .9rem; font-weight: 700; color: var(--text); }
.related-desc { font-size: .78rem; color: var(--text-muted); flex: 1; }
.related-link { font-size: .78rem; color: var(--primary); font-weight: 600; }

.blog-related-grid { display: grid; grid-template-columns: repeat(auto-fill, minmax(220px, 1fr)); gap: 12px; }
.blog-card {
  background: var(--bg-card); border: 1px solid var(--border);
  border-radius: var(--radius); padding: 18px; display: flex; flex-direction: column; gap: 8px;
  transition: border-color .15s;
}
.blog-card:hover { border-color: var(--primary); text-decoration: none; }
.blog-tag-sm   { font-size: .73rem; color: var(--text-faint); font-weight: 600; }
.blog-title-sm { font-size: .88rem; font-weight: 600; color: var(--text); flex: 1; line-height: 1.5; }
.blog-link     { font-size: .78rem; color: var(--primary); font-weight: 600; }

/* ── Toast ───────────────────────────────────────────────────────── */
.toast {
  position: fixed; bottom: 28px; left: 50%; transform: translateX(-50%) translateY(20px);
  background: #1a1a28; border: 1px solid rgba(6,182,212,.35);
  color: var(--text); padding: 10px 20px; border-radius: 8px;
  font-size: .88rem; font-weight: 500; opacity: 0;
  transition: opacity .2s, transform .2s; pointer-events: none; z-index: 999;
}
.toast.show { opacity: 1; transform: translateX(-50%) translateY(0); }

/* ── Footer ──────────────────────────────────────────────────────── */
.site-footer { background: var(--bg-card); border-top: 1px solid var(--border); padding: 44px 20px 28px; }
.footer-grid {
  max-width: 1140px; margin: 0 auto;
  display: grid; grid-template-columns: 2fr repeat(3,1fr); gap: 32px; margin-bottom: 36px;
}
@media (max-width: 700px) { .footer-grid { grid-template-columns: 1fr 1fr; } }
.footer-brand-text { font-size: .82rem; color: var(--text-faint); margin-top: 10px; }
.footer-heading { font-size: .72rem; font-weight: 700; text-transform: uppercase; letter-spacing: .1em; color: var(--text-faint); margin-bottom: 12px; }
.footer-links { display: flex; flex-direction: column; gap: 8px; }
.footer-links a { font-size: .85rem; color: var(--text-muted); }
.footer-links a:hover { color: var(--text); }
.footer-bottom {
  max-width: 1140px; margin: 0 auto; padding-top: 20px;
  border-top: 1px solid var(--border);
  display: flex; justify-content: space-between;
  font-size: .78rem; color: var(--text-faint); flex-wrap: wrap; gap: 8px;
}