/* ===== Image Lab — Compact, Mobile-First ===== */
*{margin:0;padding:0;box-sizing:border-box;}
body{font-family:'Inter',-apple-system,BlinkMacSystemFont,sans-serif;background:linear-gradient(135deg,#1a1a2e 0%,#16213e 50%,#0f3460 100%);min-height:100vh;color:#e0e0e0;}

.img-app{max-width:960px;margin:0 auto;padding:.75rem;}

/* Back button — tiny, always visible */
.back-btn{position:fixed;top:6px;left:6px;z-index:999;background:rgba(20,50,100,.8);padding:2px 8px;border-radius:3px;color:#ccc;text-decoration:none;font-size:.65rem;border:1px solid rgba(255,255,255,.15);backdrop-filter:blur(4px);}
.back-btn:hover{background:rgba(40,80,160,.9);color:#fff;}

/* Header */
.img-header{text-align:center;margin-bottom:.75rem;}
.img-header h1{font-size:1.5rem;font-weight:600;}
.img-header p{font-size:.85rem;opacity:.75;margin-top:.2rem;}

/* Upload zone */
.upload-zone{display:flex;align-items:center;gap:1rem;background:rgba(255,255,255,.06);border:2px dashed rgba(255,255,255,.2);border-radius:8px;padding:1rem 1.25rem;cursor:pointer;transition:all .25s;}
.upload-zone:hover{background:rgba(255,255,255,.1);border-color:rgba(255,255,255,.4);}
.upload-ico{font-size:2rem;flex-shrink:0;}
.upload-lbl{font-size:.95rem;font-weight:500;}
.upload-sub{font-size:.75rem;opacity:.6;}

/* Workspace */
.workspace{margin-top:.75rem;}

/* Canvas row */
.canvas-row{display:grid;grid-template-columns:1fr 1fr;gap:.5rem;margin-bottom:.5rem;}
.cvs-wrap{background:rgba(0,0,0,.35);border-radius:6px;padding:.4rem;overflow:hidden;}
.cvs-label{display:block;font-size:.7rem;font-weight:600;text-transform:uppercase;letter-spacing:.5px;opacity:.6;margin-bottom:.25rem;}
canvas{width:100%;height:auto;border-radius:3px;background:#222;display:block;}

.img-info{font-size:.7rem;opacity:.6;margin-bottom:.5rem;padding:0 .2rem;}

/* Tabs */
.tabs{display:flex;gap:3px;margin-bottom:.5rem;overflow-x:auto;-webkit-overflow-scrolling:touch;scrollbar-width:none;}
.tabs::-webkit-scrollbar{display:none;}
.tab{flex-shrink:0;padding:.4rem .7rem;background:rgba(255,255,255,.08);border:1px solid rgba(255,255,255,.12);border-radius:5px;color:#ccc;font-size:.75rem;font-weight:500;cursor:pointer;transition:all .2s;white-space:nowrap;}
.tab:hover{background:rgba(255,255,255,.15);}
.tab.active{background:rgba(74,144,226,.35);border-color:rgba(74,144,226,.5);color:#fff;}

/* Panels */
.panels{margin-bottom:.5rem;}
.panel{display:none;animation:panelIn .2s ease;}
.panel.active{display:block;}
@keyframes panelIn{from{opacity:0;}to{opacity:1;}}

/* Button grid */
.btn-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(90px,1fr));gap:4px;}
.tb{padding:.45rem .5rem;background:linear-gradient(135deg,rgba(74,144,226,.3),rgba(118,75,162,.3));border:1px solid rgba(255,255,255,.12);border-radius:5px;color:#ddd;font-size:.75rem;font-weight:500;cursor:pointer;transition:all .2s;text-align:center;}
.tb:hover{background:linear-gradient(135deg,rgba(74,144,226,.5),rgba(118,75,162,.5));transform:translateY(-1px);color:#fff;}
.tb:active{transform:translateY(0);}

/* Sliders */
.sliders{display:grid;grid-template-columns:1fr 1fr;gap:.4rem .75rem;}
.sliders label{font-size:.75rem;font-weight:500;display:flex;flex-direction:column;gap:.2rem;}
.sliders label span{color:#7ec8e3;font-weight:600;}
input[type="range"]{width:100%;height:4px;background:rgba(255,255,255,.15);border-radius:2px;outline:none;-webkit-appearance:none;}
input[type="range"]::-webkit-slider-thumb{-webkit-appearance:none;width:14px;height:14px;background:#fff;cursor:pointer;border-radius:50%;box-shadow:0 1px 4px rgba(0,0,0,.35);}
input[type="range"]::-moz-range-thumb{width:14px;height:14px;background:#fff;cursor:pointer;border-radius:50%;box-shadow:0 1px 4px rgba(0,0,0,.35);border:none;}

/* Action bar */
.actions{display:flex;gap:4px;flex-wrap:wrap;}
.act{flex:1;min-width:70px;padding:.45rem .6rem;border-radius:5px;font-size:.75rem;font-weight:600;cursor:pointer;border:none;color:#fff;transition:all .2s;}
.act:hover{filter:brightness(1.15);transform:translateY(-1px);}
.reset{background:linear-gradient(135deg,#f093fb,#f5576c);}
.undo{background:linear-gradient(135deg,#fccb90,#d57eeb);}
.dl{background:linear-gradient(135deg,#4facfe,#00f2fe);}
.newimg{background:linear-gradient(135deg,#43e97b,#38f9d7);color:#111;}

/* ===== Tablet (≤768) ===== */
@media(max-width:768px){
    .img-app{padding:.5rem;}
    .img-header h1{font-size:1.25rem;}
    .img-header p{font-size:.8rem;}
    .upload-zone{padding:.75rem 1rem;}
    .upload-ico{font-size:1.75rem;}
    .canvas-row{grid-template-columns:1fr 1fr;gap:.4rem;}
    .sliders{grid-template-columns:1fr 1fr;}
    .btn-grid{grid-template-columns:repeat(auto-fill,minmax(80px,1fr));}
}

/* ===== Phone (≤480) ===== */
@media(max-width:480px){
    .img-app{padding:.35rem;}
    .img-header h1{font-size:1.1rem;}
    .img-header p{font-size:.75rem;}
    .upload-zone{flex-direction:column;text-align:center;padding:.6rem;gap:.4rem;}
    .upload-ico{font-size:1.5rem;}
    .upload-lbl{font-size:.85rem;}
    .canvas-row{grid-template-columns:1fr;gap:.35rem;}
    .cvs-wrap{padding:.3rem;}
    .tabs{gap:2px;}
    .tab{padding:.35rem .5rem;font-size:.7rem;}
    .btn-grid{grid-template-columns:repeat(3,1fr);gap:3px;}
    .tb{padding:.4rem .3rem;font-size:.7rem;}
    .sliders{grid-template-columns:1fr;}
    .actions{gap:3px;}
    .act{font-size:.7rem;padding:.4rem .5rem;min-width:60px;}
}

/* ===== Small phone (≤360) ===== */
@media(max-width:360px){
    .img-header h1{font-size:1rem;}
    .btn-grid{grid-template-columns:repeat(2,1fr);}
    .tab{font-size:.65rem;padding:.3rem .4rem;}
}