/* ── Reset & Base ── */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
html{scroll-behavior:smooth;font-size:16px}

/* ── Design System Variables ── */
:root{
  --bg:#000000;
  --bg2:#080c12;
  --sur:#0d1117;
  --brd:rgba(56,139,253,.12);
  --brd2:rgba(56,139,253,.30);
  --tx1:#e6edf3;
  --tx2:#7d8590;
  --tx3:#3d4450;
  --acc:#388bfd;
  --acc2:#58a6ff;
  --acc3:#79c0ff;
  --glow:rgba(56,139,253,.18);
  --font:'Inter',-apple-system,BlinkMacSystemFont,'Segoe UI',system-ui,sans-serif;
  --ease-spring:cubic-bezier(.34,1.56,.64,1);
  --tr:.25s ease;
}
[data-theme="light"]{
  --bg:#ffffff;
  --bg2:#f6f8fa;
  --sur:#eaeef2;
  --brd:rgba(31,111,235,.12);
  --brd2:rgba(31,111,235,.28);
  --tx1:#1f2328;
  --tx2:#636c76;
  --tx3:#aab1ba;
  --acc:#1f6feb;
  --acc2:#388bfd;
  --acc3:#58a6ff;
  --glow:rgba(31,111,235,.10);
}

html{background:var(--bg)}
body{
  font-family:var(--font);background:var(--bg);color:var(--tx1);
  line-height:1.6;-webkit-font-smoothing:antialiased;overflow-x:hidden;
  transition:background .4s,color .3s
}
a{color:inherit;text-decoration:none}
h1,h2,h3{letter-spacing:-.02em;line-height:1.15;color:var(--tx1)}
html.no-transition *,html.no-transition *::before,html.no-transition *::after{transition:none!important}
button{font-family:var(--font);cursor:pointer}

/* ── Scroll progress ── */
.scroll-bar{
  position:fixed;top:0;left:0;height:2px;width:0%;z-index:999;
  background:linear-gradient(90deg,var(--acc),var(--acc2));transition:width .1s linear
}

/* ── Navbar ── */
.navbar{
  position:sticky;top:0;z-index:200;
  background:transparent;display:flex;justify-content:center;
  padding:12px 20px;transition:padding .4s ease
}
.navbar.scrolled{padding:6px 20px}

.nav-inner{
  display:flex;align-items:center;justify-content:space-between;
  height:52px;width:100%;max-width:1100px;
  padding:0 10px 0 16px;border-radius:999px;
  background:rgba(0,0,0,.70);
  backdrop-filter:blur(40px) saturate(180%);
  -webkit-backdrop-filter:blur(40px) saturate(180%);
  border:1px solid rgba(56,139,253,.18);
  box-shadow:inset 0 1px 0 rgba(88,166,255,.06),0 8px 40px rgba(0,0,0,.6),0 2px 8px rgba(0,0,0,.4);
  transition:height .4s var(--ease-spring),padding .4s ease,background .35s ease
}
[data-theme="light"] .nav-inner{
  background:rgba(255,255,255,.82);border-color:rgba(56,139,253,.18);
  box-shadow:inset 0 1.5px 0 rgba(56,139,253,.08),0 8px 40px rgba(0,0,0,.06)
}
.navbar.scrolled .nav-inner{
  height:44px;
  background:rgba(0,0,0,.88)
}
[data-theme="light"] .navbar.scrolled .nav-inner{background:rgba(255,255,255,.95)}

.nav-brand{display:flex;align-items:center;flex-shrink:0}

.logo-pill{
  background:#fff;border-radius:999px;
  padding:4px 14px 4px 8px;display:flex;align-items:center;
  height:38px;transition:box-shadow .25s,background .3s
}
[data-theme="light"] .logo-pill{background:transparent}
.logo-pill:hover{box-shadow:0 0 0 2px rgba(56,139,253,.35)}
.nav-logo{height:28px;width:auto;object-fit:contain;display:block}

.nav-right{display:flex;align-items:center;gap:12px}

.nav-back{
  font-size:.83rem;font-weight:600;color:var(--tx2);
  padding:7px 14px;border-radius:99px;
  border:1px solid var(--brd);
  background:transparent;
  transition:color .18s,background .18s,border-color .18s
}
.nav-back:hover{color:var(--acc);background:rgba(56,139,253,.08);border-color:var(--brd2)}

/* Toggle */
.toggle-check{position:absolute;opacity:0;width:0;height:0}
.toggle-wrap{display:flex;align-items:center;cursor:pointer;flex-shrink:0}
.toggle-track{
  position:relative;width:52px;height:28px;border-radius:999px;
  background:#1c2333;border:1.5px solid rgba(56,139,253,.25);
  transition:background .3s,border-color .3s;overflow:hidden
}
[data-theme="light"] .toggle-track{background:#e8f0fe;border-color:rgba(31,111,235,.25)}
.toggle-thumb{
  position:absolute;top:3px;left:3px;
  width:20px;height:20px;border-radius:50%;
  background:linear-gradient(135deg,#388bfd,#79c0ff);
  transition:transform .4s cubic-bezier(.34,1.56,.64,1),background .3s;
  z-index:2;box-shadow:0 2px 6px rgba(0,0,0,.3)
}
.toggle-check:checked ~ .toggle-track .toggle-thumb{transform:translateX(24px)}
[data-theme="light"] .toggle-thumb{background:linear-gradient(135deg,#fbbf24,#f97316)}
.toggle-icon{
  position:absolute;top:50%;transform:translateY(-50%);
  display:flex;align-items:center;justify-content:center;
  z-index:1;transition:opacity .25s
}
.toggle-icon-sun{left:6px;color:#fbbf24}
.toggle-icon-moon{right:6px;color:#79c0ff}
.toggle-icon-sun{opacity:0}
.toggle-icon-moon{opacity:1}
[data-theme="light"] .toggle-icon-sun{opacity:1}
[data-theme="light"] .toggle-icon-moon{opacity:0}

/* ── Tool Main ── */
.tool-main{
  max-width:1200px;margin:0 auto;
  padding:32px 24px 24px
}

/* ── Tool Header ── */
.tool-header{
  margin-bottom:32px;
  display:flex;flex-direction:column;gap:14px
}
.tool-title-area h1{
  font-size:clamp(1.8rem,4vw,2.8rem);font-weight:900;margin-bottom:6px
}
.accent{
  background:linear-gradient(135deg,var(--acc),var(--acc3));
  -webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text
}
.tool-tagline{font-size:1rem;color:var(--tx2);max-width:540px}
.tool-badges-row{display:flex;gap:8px;flex-wrap:wrap}
.badge{font-size:.7rem;font-weight:700;padding:4px 12px;border-radius:99px}
.badge-free{background:rgba(56,139,253,.1);color:var(--acc);border:1px solid rgba(56,139,253,.22)}
.badge-offline{background:rgba(52,211,153,.1);color:#34d399;border:1px solid rgba(52,211,153,.22)}
.badge-ai{background:rgba(163,200,64,.1);color:#84cc16;border:1px solid rgba(163,200,64,.22)}

/* ── Upload Zone ── */
@keyframes fade-up{from{opacity:0;transform:translateY(20px)}to{opacity:1;transform:translateY(0)}}

.upload-zone{
  border:2px dashed var(--brd2);border-radius:20px;
  background:var(--sur);
  transition:border-color .2s,background .2s,box-shadow .2s;
  cursor:pointer;
  animation:fade-up .4s ease both;
  min-height:280px;display:flex;align-items:center;justify-content:center
}
.upload-zone:hover,.upload-zone.drag-over{
  border-color:var(--acc);
  background:rgba(56,139,253,.04);
  box-shadow:0 0 0 4px var(--glow)
}
.upload-zone.drag-over{
  border-style:solid;
  box-shadow:0 0 0 6px var(--glow),inset 0 0 40px rgba(56,139,253,.05)
}
.upload-inner{
  display:flex;flex-direction:column;align-items:center;
  gap:12px;padding:48px 24px;text-align:center;
  pointer-events:none
}
.upload-icon{
  width:80px;height:80px;border-radius:20px;
  background:rgba(56,139,253,.08);border:1px solid var(--brd2);
  display:flex;align-items:center;justify-content:center;
  color:var(--acc);
  transition:transform .2s var(--ease-spring),background .2s
}
.upload-zone:hover .upload-icon,.upload-zone.drag-over .upload-icon{
  transform:scale(1.06);background:rgba(56,139,253,.14)
}
.upload-title{font-size:1.1rem;font-weight:700;color:var(--tx1)}
.upload-sub{font-size:.85rem;color:var(--tx3)}
.btn-upload{
  margin-top:4px;
  padding:10px 24px;border-radius:999px;
  background:var(--acc);color:#fff;border:none;
  font-size:.875rem;font-weight:700;
  pointer-events:all;
  transition:opacity .2s,transform .2s var(--ease-spring),box-shadow .2s
}
.btn-upload:hover{opacity:.88;transform:translateY(-1px);box-shadow:0 6px 20px rgba(56,139,253,.4)}

/* ── Processing ── */
@keyframes spin{to{transform:rotate(360deg)}}
@keyframes progress-pulse{0%,100%{opacity:1}50%{opacity:.6}}

.processing{
  display:flex;flex-direction:column;align-items:center;
  gap:16px;padding:64px 24px;text-align:center
}
.processing-spinner{
  width:52px;height:52px;border-radius:50%;
  border:3px solid var(--brd2);
  border-top-color:var(--acc);
  animation:spin .8s linear infinite
}
.processing-text{font-size:1rem;font-weight:600;color:var(--tx2)}
.processing-bar{
  width:280px;height:4px;border-radius:99px;
  background:var(--brd2);overflow:hidden
}
.processing-fill{
  height:100%;border-radius:99px;
  background:linear-gradient(90deg,var(--acc),var(--acc3));
  width:0%;transition:width .3s ease
}

/* ── Workspace ── */
.workspace{
  display:grid;
  grid-template-columns:1fr 380px;
  height:calc(100vh - 230px);
  min-height:560px;
  gap:24px;
  animation:fade-up .4s ease both
}

/* ── Preview Panel ── */
.preview-panel{
  display:flex;flex-direction:column;gap:12px;
  background:var(--sur);border:1px solid var(--brd);border-radius:20px;
  padding:20px;overflow:hidden;min-height:0
}
.preview-tabs{
  display:flex;gap:4px;
  background:var(--bg2);border-radius:99px;
  padding:3px;border:1px solid var(--brd)
}
.preview-tab{
  flex:1;padding:7px 12px;border-radius:99px;
  border:none;background:transparent;
  font-size:.8rem;font-weight:600;color:var(--tx2);
  transition:background .2s,color .2s
}
.preview-tab.active{background:var(--acc);color:#fff}
.preview-tab:not(.active):hover{background:rgba(56,139,253,.08);color:var(--tx1)}

.preview-canvas-wrap{
  flex:1;min-height:300px;border-radius:16px;overflow:hidden;
  background-color:#1a1a1a;
  background-image:
    linear-gradient(45deg,#2a2a2a 25%,transparent 25%),
    linear-gradient(-45deg,#2a2a2a 25%,transparent 25%),
    linear-gradient(45deg,transparent 75%,#2a2a2a 75%),
    linear-gradient(-45deg,transparent 75%,#2a2a2a 75%);
  background-size:16px 16px;
  background-position:0 0,0 8px,8px -8px,-8px 0;
  display:flex;align-items:center;justify-content:center;
  position:relative
}
[data-theme="light"] .preview-canvas-wrap{
  background-color:#f0f0f0;
  background-image:
    linear-gradient(45deg,#e0e0e0 25%,transparent 25%),
    linear-gradient(-45deg,#e0e0e0 25%,transparent 25%),
    linear-gradient(45deg,transparent 75%,#e0e0e0 75%),
    linear-gradient(-45deg,transparent 75%,#e0e0e0 75%)
}
#previewCanvas{
  max-width:100%;max-height:520px;
  object-fit:contain;display:block;border-radius:8px
}
.preview-img{
  max-width:100%;max-height:520px;
  object-fit:contain;border-radius:8px
}
.preview-img.hidden,.compare-view.hidden{display:none}

/* Compare view */
.compare-view{
  width:100%;height:100%;position:relative;
  display:flex;gap:4px
}
.compare-original,.compare-result{
  width:50%;height:100%;object-fit:contain;
  border-radius:8px;display:block
}
.compare-label{
  position:absolute;bottom:8px;font-size:.7rem;font-weight:700;
  color:#fff;background:rgba(0,0,0,.55);border-radius:6px;
  padding:3px 8px;pointer-events:none
}
.compare-label-before{left:8px}
.compare-label-after{right:8px}

.preview-meta{
  font-size:.78rem;color:var(--tx3);
  text-align:center;min-height:16px
}

/* ── Controls Panel ── */
.controls-panel{
  display:flex;flex-direction:column;gap:0;
  background:var(--sur);border:1px solid var(--brd);border-radius:20px;
  overflow-y:auto;overflow-x:hidden;
  scrollbar-width:thin;scrollbar-color:var(--brd2) transparent
}
.controls-panel::-webkit-scrollbar{width:4px}
.controls-panel::-webkit-scrollbar-thumb{background:var(--brd2);border-radius:99px}
.ctrl-section{
  padding:18px 20px;border-bottom:1px solid var(--brd)
}
.ctrl-section:last-child{border-bottom:none}
.ctrl-heading{
  font-size:.8rem;font-weight:700;text-transform:uppercase;
  letter-spacing:.1em;color:var(--tx3);margin-bottom:12px
}
.ctrl-label{
  display:block;font-size:.8rem;font-weight:600;color:var(--tx2);
  margin-bottom:8px
}
.ctrl-label span{color:var(--acc);font-variant-numeric:tabular-nums}

/* Background type grid */
.bg-type-grid{
  display:grid;grid-template-columns:repeat(4,1fr);
  gap:8px;margin-bottom:0
}
.bg-type-btn{
  display:flex;flex-direction:column;align-items:center;gap:6px;
  padding:8px 4px;border-radius:12px;
  border:1.5px solid var(--brd);background:var(--bg2);
  color:var(--tx2);font-size:.7rem;font-weight:600;
  transition:border-color .2s,background .2s,color .2s
}
.bg-type-btn:hover{border-color:var(--acc);color:var(--acc)}
.bg-type-btn.active{border-color:var(--acc);background:rgba(56,139,253,.08);color:var(--acc)}
.bg-type-preview{
  width:52px;height:40px;border-radius:8px;overflow:hidden;
  background:var(--sur);border:1px solid var(--brd)
}
.bg-type-preview.checker{
  background-color:#808080;
  background-image:
    linear-gradient(45deg,#606060 25%,transparent 25%),
    linear-gradient(-45deg,#606060 25%,transparent 25%),
    linear-gradient(45deg,transparent 75%,#606060 75%),
    linear-gradient(-45deg,transparent 75%,#606060 75%);
  background-size:8px 8px;
  background-position:0 0,0 4px,4px -4px,-4px 0
}
.bg-type-img-icon{
  display:flex;align-items:center;justify-content:center;
  background:#1a1a2e;color:#a78bfa
}

/* bg-option sub-panels */
.bg-option{margin-top:12px}

/* Color row */
.color-row{display:flex;gap:8px;align-items:center;margin-bottom:10px}
.color-swatch-input{
  width:40px;height:40px;border-radius:10px;border:1.5px solid var(--brd2);
  padding:2px;background:var(--sur);cursor:pointer;
  transition:border-color .2s
}
.color-swatch-input::-webkit-color-swatch-wrapper{padding:0;border-radius:7px}
.color-swatch-input::-webkit-color-swatch{border:none;border-radius:7px}
.color-swatch-input:hover{border-color:var(--acc)}
.hex-input{
  flex:1;padding:9px 12px;border-radius:10px;
  border:1.5px solid var(--brd);background:var(--bg2);
  color:var(--tx1);font-size:.875rem;font-family:var(--font);
  outline:none;transition:border-color .2s
}
.hex-input:focus{border-color:var(--acc)}

/* Color presets */
.color-presets{
  display:flex;flex-wrap:wrap;gap:6px
}
.color-preset{
  width:26px;height:26px;border-radius:6px;border:1.5px solid transparent;
  cursor:pointer;transition:transform .15s,border-color .15s
}
.color-preset:hover{transform:scale(1.15);border-color:var(--tx2)}
.color-preset.active{border-color:var(--acc);transform:scale(1.15)}

/* Gradient grid */
.gradient-grid{
  display:grid;grid-template-columns:repeat(4,1fr);gap:8px
}
.gradient-swatch{
  height:40px;border-radius:10px;border:1.5px solid transparent;
  cursor:pointer;transition:transform .15s,border-color .15s,box-shadow .15s;
  position:relative;overflow:hidden
}
.gradient-swatch:hover{transform:scale(1.05);border-color:var(--brd2)}
.gradient-swatch.active{border-color:var(--acc);box-shadow:0 0 0 2px var(--glow)}
.gradient-swatch-name{
  position:absolute;bottom:0;left:0;right:0;
  font-size:.55rem;font-weight:700;color:#fff;
  text-align:center;padding:2px 0;
  background:rgba(0,0,0,.4);
  text-shadow:0 1px 2px rgba(0,0,0,.6)
}

/* Gradient custom row */
.gradient-custom-row{
  display:flex;gap:8px;align-items:center
}
.gradient-custom-row .color-swatch-input{width:44px;height:36px;flex-shrink:0}
.ctrl-select{
  flex:1;padding:8px 10px;border-radius:10px;
  border:1.5px solid var(--brd);background:var(--bg2);
  color:var(--tx1);font-size:.8rem;font-family:var(--font);
  outline:none;cursor:pointer;
  transition:border-color .2s
}
.ctrl-select:focus,.ctrl-select:hover{border-color:var(--acc)}

/* BG image upload */
.bg-img-upload{
  border:1.5px dashed var(--brd2);border-radius:12px;
  padding:16px;text-align:center;cursor:pointer;
  display:flex;flex-direction:column;align-items:center;gap:8px;
  color:var(--tx3);font-size:.8rem;
  transition:border-color .2s,background .2s
}
.bg-img-upload:hover{border-color:var(--acc);background:rgba(56,139,253,.04);color:var(--acc)}

/* Segment group */
.segment-group{
  display:flex;background:var(--bg2);border-radius:99px;
  border:1px solid var(--brd);padding:3px;gap:2px
}
.seg-btn{
  flex:1;padding:6px 10px;border-radius:99px;
  border:none;background:transparent;
  font-size:.78rem;font-weight:600;color:var(--tx2);
  transition:background .2s,color .2s
}
.seg-btn.active{background:var(--acc);color:#fff}
.seg-btn:not(.active):hover{background:rgba(56,139,253,.08);color:var(--tx1)}

/* Frame grid */
.frame-grid{
  display:grid;grid-template-columns:repeat(4,1fr);gap:8px
}
.frame-btn{
  display:flex;flex-direction:column;align-items:center;
  padding:4px;border-radius:10px;
  border:1.5px solid var(--brd);background:var(--bg2);
  transition:border-color .2s,background .2s
}
.frame-btn:hover{border-color:var(--brd2)}
.frame-btn.active{border-color:var(--acc);background:rgba(56,139,253,.08)}
.frame-preview{
  width:100%;aspect-ratio:1;border-radius:6px;
  background:rgba(56,139,253,.06);
  display:flex;align-items:center;justify-content:center;
  font-size:.6rem;font-weight:700;color:var(--tx2);
  text-align:center;padding:2px;
  overflow:hidden
}
.polaroid-preview{
  border:2px solid white;padding-bottom:10px;
  background:white;color:#444
}

/* Sliders */
.ctrl-slider{
  width:100%;height:4px;border-radius:99px;
  appearance:none;-webkit-appearance:none;
  background:linear-gradient(to right,var(--acc) 0%,var(--acc) calc(var(--pct,20%) * 1%),var(--brd2) calc(var(--pct,20%) * 1%),var(--brd2) 100%);
  outline:none;cursor:pointer;
  margin-bottom:4px
}
.ctrl-slider::-webkit-slider-thumb{
  appearance:none;-webkit-appearance:none;
  width:16px;height:16px;border-radius:50%;
  background:var(--acc);
  box-shadow:0 0 0 3px var(--bg),0 0 0 5px var(--acc);
  transition:transform .15s var(--ease-spring)
}
.ctrl-slider::-webkit-slider-thumb:hover{transform:scale(1.2)}
.ctrl-slider::-moz-range-thumb{
  width:16px;height:16px;border-radius:50%;border:none;
  background:var(--acc);box-shadow:0 0 0 3px var(--bg),0 0 0 5px var(--acc)
}

/* Export row */
.export-row{
  display:grid;grid-template-columns:1fr 1fr;gap:12px;margin-bottom:12px
}
#customSizeRow{
  display:flex;gap:8px;margin-bottom:12px
}
.ctrl-input{
  flex:1;padding:9px 12px;border-radius:10px;
  border:1.5px solid var(--brd);background:var(--bg2);
  color:var(--tx1);font-size:.875rem;font-family:var(--font);
  outline:none;transition:border-color .2s
}
.ctrl-input:focus{border-color:var(--acc)}

/* Download button */
.btn-download{
  display:flex;align-items:center;justify-content:center;gap:8px;
  width:100%;padding:14px;border-radius:12px;
  background:var(--acc);color:#fff;border:none;
  font-size:.95rem;font-weight:700;
  margin-bottom:10px;
  transition:opacity .2s,transform .2s var(--ease-spring),box-shadow .2s
}
.btn-download:hover{opacity:.88;transform:translateY(-1px);box-shadow:0 8px 24px rgba(56,139,253,.45)}
.btn-download:active{transform:translateY(0)}

.btn-secondary-action{
  display:block;width:100%;padding:11px;border-radius:12px;
  background:transparent;color:var(--tx2);
  border:1.5px solid var(--brd);font-size:.875rem;font-weight:600;
  transition:border-color .2s,color .2s,background .2s
}
.btn-secondary-action:hover{border-color:var(--brd2);color:var(--tx1);background:var(--bg2)}

/* ── Responsive ── */
@media(max-width:900px){
  .workspace{
    grid-template-columns:1fr;
    height:auto;min-height:0;
  }
  .preview-panel{order:1}
  .controls-panel{order:2;max-height:none;overflow-y:visible}
}
@media(max-width:600px){
  .tool-main{padding:20px 16px 60px}
  .tool-title-area h1{font-size:1.7rem}
  .bg-type-grid{grid-template-columns:repeat(4,1fr)}
  .frame-grid{grid-template-columns:repeat(4,1fr)}
  .export-row{grid-template-columns:1fr}
  .nav-back{display:none}
}