/* ========== Reset & Base ========== */
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
:root{
  --primary:#3498DB;--primary-dim:rgba(52,152,219,.15);
  --secondary:#2980B9;--accent:#2ECC71;--accent-dim:rgba(46,204,113,.12);
  --bg:#0A0F1A;--surface:#111827;--surface2:#1A2235;
  --border:rgba(255,255,255,.08);--text:#F1F5F9;--text-dim:#94A3B8;
  --radius:12px;--font:'Inter',system-ui,-apple-system,sans-serif;
  --transition:250ms ease;
}
html{font-size:16px;scroll-behavior:smooth}
body{background:var(--bg);color:var(--text);font-family:var(--font);line-height:1.6;min-height:100vh}

/* ========== Header ========== */
.header{position:sticky;top:0;z-index:100;backdrop-filter:blur(16px);-webkit-backdrop-filter:blur(16px);background:rgba(10,15,26,.75);border-bottom:1px solid var(--border)}
.header-inner{max-width:1200px;margin:0 auto;padding:1rem 1.5rem;display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:1rem}
.logo{display:flex;align-items:center;gap:.75rem;color:var(--primary)}
.logo h1{font-size:1.25rem;font-weight:700;background:linear-gradient(135deg,var(--primary),var(--accent));-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.stats{display:flex;align-items:center;gap:.75rem;font-size:.875rem;color:var(--text-dim)}
.stat-divider{opacity:.3}

/* ========== Main ========== */
.main{max-width:1200px;margin:0 auto;padding:1.5rem}

/* ========== Drop Zone ========== */
.drop-zone{border:2px dashed var(--border);border-radius:var(--radius);padding:3rem 2rem;text-align:center;cursor:pointer;transition:all var(--transition);background:var(--surface)}
.drop-zone:hover,.drop-zone.dragover{border-color:var(--primary);background:var(--primary-dim)}
.drop-zone:focus-visible{outline:2px solid var(--primary);outline-offset:2px}
.drop-icon{width:48px;height:48px;color:var(--primary);margin-bottom:1rem;opacity:.7;transition:opacity var(--transition)}
.drop-zone:hover .drop-icon{opacity:1}
.drop-title{font-size:1.125rem;font-weight:600;margin-bottom:.25rem}
.drop-subtitle{font-size:.875rem;color:var(--text-dim)}

/* ========== Toolbar ========== */
.toolbar{display:flex;align-items:center;justify-content:space-between;flex-wrap:wrap;gap:1rem;margin:1.5rem 0;padding:1rem 1.25rem;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius)}
.toolbar-left,.toolbar-right{display:flex;align-items:center;gap:.75rem;flex-wrap:wrap}
.search-box{display:flex;align-items:center;gap:.5rem;background:var(--surface2);border:1px solid var(--border);border-radius:8px;padding:.5rem .75rem;transition:border-color var(--transition)}
.search-box:focus-within{border-color:var(--primary)}
.search-box input{background:none;border:none;color:var(--text);font-size:.875rem;outline:none;width:160px}
.search-box svg{color:var(--text-dim);flex-shrink:0}
.naming-label{font-size:.8rem;color:var(--text-dim);display:flex;align-items:center;gap:.5rem}
.naming-label input{background:var(--surface2);border:1px solid var(--border);border-radius:6px;padding:.4rem .6rem;color:var(--text);font-size:.8rem;width:80px;outline:none;transition:border-color var(--transition)}
.naming-label input:focus{border-color:var(--primary)}

/* ========== Buttons ========== */
.btn{display:inline-flex;align-items:center;gap:.4rem;padding:.5rem 1rem;border:none;border-radius:8px;font-size:.8rem;font-weight:600;cursor:pointer;transition:all var(--transition);font-family:var(--font)}
.btn-primary{background:linear-gradient(135deg,var(--primary),var(--secondary));color:#fff}
.btn-primary:hover{filter:brightness(1.15);transform:translateY(-1px)}
.btn-secondary{background:var(--surface2);color:var(--text);border:1px solid var(--border)}
.btn-secondary:hover{border-color:var(--primary);color:var(--primary)}
.btn-danger{background:rgba(239,68,68,.15);color:#EF4444;border:1px solid rgba(239,68,68,.2)}
.btn-danger:hover{background:rgba(239,68,68,.25)}
.btn-copy{background:var(--primary-dim);color:var(--primary);border:none;padding:.35rem .75rem;border-radius:6px;font-size:.75rem;font-weight:600;cursor:pointer;transition:all var(--transition);font-family:var(--font)}
.btn-copy:hover{background:var(--primary);color:#fff}

/* ========== Sprite Grid ========== */
.sprite-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(180px,1fr));gap:1rem;margin-top:1.5rem}
.sprite-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:1rem;transition:all var(--transition);position:relative;overflow:hidden}
.sprite-card:hover{border-color:var(--primary);transform:translateY(-2px);box-shadow:0 8px 24px rgba(52,152,219,.12)}
.sprite-preview{width:100%;height:100px;display:flex;align-items:center;justify-content:center;margin-bottom:.75rem;background:var(--surface2);border-radius:8px;padding:.75rem}
.sprite-preview svg{max-width:100%;max-height:100%;color:var(--text)}
.sprite-name{font-size:.8rem;font-weight:600;margin-bottom:.25rem;word-break:break-all}
.sprite-size{font-size:.7rem;color:var(--text-dim)}
.sprite-actions{display:flex;gap:.5rem;margin-top:.75rem}
.sprite-actions .btn{flex:1;justify-content:center;padding:.4rem;font-size:.7rem}
.sprite-remove{position:absolute;top:.5rem;right:.5rem;width:24px;height:24px;border-radius:50%;background:rgba(239,68,68,.2);border:none;color:#EF4444;cursor:pointer;display:flex;align-items:center;justify-content:center;opacity:0;transition:opacity var(--transition);font-size:.75rem}
.sprite-card:hover .sprite-remove{opacity:1}
.sprite-remove:hover{background:rgba(239,68,68,.4)}

/* ========== Size Report ========== */
.section-title{font-size:1rem;font-weight:700;margin-bottom:1rem;display:flex;align-items:center;gap:.5rem}
.section-title::before{content:'';width:4px;height:20px;background:linear-gradient(to bottom,var(--primary),var(--accent));border-radius:2px}
.size-report{margin-top:2rem}
.report-cards{display:grid;grid-template-columns:repeat(auto-fit,minmax(180px,1fr));gap:1rem}
.report-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:1.25rem;text-align:center}
.report-card.highlight{background:var(--accent-dim);border-color:rgba(46,204,113,.25)}
.report-label{font-size:.75rem;color:var(--text-dim);display:block;margin-bottom:.5rem;text-transform:uppercase;letter-spacing:.05em}
.report-value{font-size:1.5rem;font-weight:700}
.report-value.accent{color:var(--primary)}
.report-card.highlight .report-value{color:var(--accent)}

/* ========== Output ========== */
.output-section{margin-top:2rem}
.code-block{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);overflow:hidden}
.code-header{display:flex;justify-content:space-between;align-items:center;padding:.75rem 1rem;border-bottom:1px solid var(--border);font-size:.8rem;font-weight:600;color:var(--text-dim)}
.code-block pre{padding:1rem;overflow-x:auto;font-size:.75rem;line-height:1.7;color:var(--text-dim);max-height:400px;overflow-y:auto}
.code-block code{font-family:'Fira Code','Cascadia Code',monospace}

/* ========== Toast ========== */
.toast{position:fixed;bottom:2rem;left:50%;transform:translateX(-50%) translateY(100px);background:var(--surface2);color:var(--text);padding:.75rem 1.5rem;border-radius:var(--radius);font-size:.875rem;font-weight:500;border:1px solid var(--primary);box-shadow:0 8px 32px rgba(0,0,0,.4);transition:transform 300ms ease;z-index:9999;pointer-events:none}
.toast.show{transform:translateX(-50%) translateY(0)}

/* ========== Responsive ========== */
@media(max-width:768px){
  .header-inner{flex-direction:column;align-items:flex-start}
  .toolbar{flex-direction:column;align-items:stretch}
  .toolbar-left,.toolbar-right{justify-content:flex-start}
  .sprite-grid{grid-template-columns:repeat(auto-fill,minmax(140px,1fr))}
  .report-cards{grid-template-columns:1fr}
}
@media(max-width:480px){
  .main{padding:1rem}
  .drop-zone{padding:2rem 1rem}
  .sprite-grid{grid-template-columns:1fr 1fr}
}