:root{color-scheme:light;--bg: #f6f7f8;--panel: #ffffff;--ink: #171b1f;--muted: #667078;--line: #dfe4e8;--accent: #128c7e;--accent-dark: #0b6e63;--danger-bg: #fff3f1;--danger: #9a3628;--radius: 8px;--preview-height: min(43vh, 390px);font-family:Inter,ui-sans-serif,system-ui,-apple-system,BlinkMacSystemFont,Segoe UI,sans-serif}*{box-sizing:border-box}body{margin:0;min-height:100vh;min-width:320px;background:linear-gradient(180deg,#dff8eead,#f6f7f800 340px),var(--bg);color:var(--ink);overflow:hidden}button,input{font:inherit}button{border:0}.app-shell{display:grid;grid-template-rows:auto 1fr;width:min(1180px,calc(100% - 32px));min-height:100vh;margin:0 auto;padding:16px 0}.topbar{position:sticky;top:0;z-index:10;display:flex;align-items:center;justify-content:space-between;gap:16px;min-height:62px;margin-bottom:14px;padding:12px 14px;border:1px solid rgba(223,228,232,.9);border-radius:var(--radius);background:#ffffffe0;box-shadow:0 12px 38px #171b1f14;-webkit-backdrop-filter:blur(14px);backdrop-filter:blur(14px)}.brand{display:inline-flex;align-items:center;gap:9px;min-height:40px;font-weight:800;line-height:1}.brand-mark{display:grid;width:34px;height:34px;place-items:center;border-radius:var(--radius);background:var(--ink);color:#fff}.nav-links,.coffee-link{display:inline-flex;align-items:center}.nav-links{gap:8px;color:var(--muted);font-size:.94rem;font-weight:700;line-height:1}.coffee-link svg{transform-origin:50% 70%;animation:coffee-wiggle 4.8s ease-in-out infinite}.coffee-link{display:inline-flex;align-items:center;justify-content:center;gap:7px;min-height:38px;padding:0 14px;border-radius:var(--radius);background:#fff7ed;color:#9a4f12;border:1px solid #fed7aa;text-decoration:none;line-height:1}.tool-card{display:grid;grid-template-rows:auto 1fr;gap:14px;align-self:start;min-width:0;min-height:0;padding:18px;border:1px solid var(--line);border-radius:var(--radius);background:var(--panel);box-shadow:0 18px 60px #171b1f14}.intro{text-align:center}.intro h1{margin:0;font-size:clamp(2rem,4.2vw,4.2rem);line-height:.95;letter-spacing:0}.intro p{margin:10px 0 0;color:var(--muted);font-size:1rem}.upload-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;min-width:0;padding:0 16px;border:1.5px dashed #b9c4cb;border-radius:var(--radius);background:#fbfcfc;color:var(--muted);font-weight:800;cursor:pointer;transition:border-color .16s ease,background .16s ease}.upload-button.dragging{border-color:var(--accent);background:#eef9f7}.upload-button input{position:absolute;width:1px;height:1px;overflow:hidden;clip:rect(0 0 0 0)}.upload-button svg{color:var(--accent)}.file-row{display:flex;align-items:center;gap:8px;width:100%;min-width:0;min-height:50px;margin-top:0;padding:10px 12px;border:1px solid var(--line);border-radius:var(--radius);color:var(--muted);overflow:hidden}.file-row.placeholder{color:#8a949b}.file-row span{min-width:0;max-width:100%;flex:1;overflow:hidden;text-overflow:ellipsis;white-space:nowrap}.file-row svg,.file-row button,.file-row-spacer{flex:0 0 auto}.file-row button{display:grid;width:28px;height:28px;place-items:center;border-radius:var(--radius);background:#eef1f3;color:var(--ink);cursor:pointer}.file-row-spacer{width:28px;height:28px}.original-toolbar{display:grid;grid-template-columns:1fr 1fr;gap:10px;min-width:0;margin-top:0}.primary-button,.secondary-button{display:inline-flex;align-items:center;justify-content:center;gap:8px;min-height:46px;min-width:0;border-radius:var(--radius);font-weight:800;cursor:pointer}.primary-button{background:var(--ink);color:#fff}.secondary-button{padding:0 14px;background:var(--accent);color:#fff;white-space:nowrap}.primary-button:disabled,.secondary-button:disabled{cursor:not-allowed;opacity:.45}.error-box{margin-top:12px;padding:11px 12px;border-radius:var(--radius);font-size:.92rem;line-height:1.45}.error-box{background:var(--danger-bg);color:var(--danger)}.preview-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:16px;min-width:0;min-height:0;margin-top:0}.preview-card{display:grid;grid-template-rows:auto var(--preview-height) 50px 46px;row-gap:10px;min-width:0;min-height:0;overflow:hidden}.result-card{grid-template-rows:auto var(--preview-height) 50px 46px}.preview-header{display:flex;align-items:center;justify-content:space-between;gap:10px;margin-bottom:0;font-weight:800}.preview-header small{display:inline-flex;align-items:center;gap:4px;color:var(--accent-dark)}.preview-surface{display:grid;height:var(--preview-height);min-height:0;place-items:center;overflow:hidden;border:1px solid var(--line);border-radius:var(--radius)}.original-surface{background:#f1f3f4}.original-surface.dragging{border-color:var(--accent);background:#eef9f7;box-shadow:inset 0 0 0 2px #128c7e29}.checkerboard{background-color:#fff;background-image:linear-gradient(45deg,#dce2e6 25%,transparent 25%),linear-gradient(-45deg,#dce2e6 25%,transparent 25%),linear-gradient(45deg,transparent 75%,#dce2e6 75%),linear-gradient(-45deg,transparent 75%,#dce2e6 75%);background-position:0 0,0 10px,10px -10px,-10px 0;background-size:20px 20px}.white-bg{background:#fff}.color-bg{background:linear-gradient(135deg,#dff8ee,#d8edff)}.preview-surface img{display:block;width:auto;max-width:92%;max-height:calc(var(--preview-height) - 36px);object-fit:contain}.empty-state{display:inline-flex;align-items:center;justify-content:center;gap:8px;padding:18px;color:var(--muted);font-weight:700;text-align:center}.drop-empty-state{display:grid;place-items:center;gap:8px;padding:20px;color:var(--muted);text-align:center}.drop-empty-icon{display:grid;width:58px;height:58px;place-items:center;border:1px solid rgba(18,140,126,.16);border-radius:18px;background:linear-gradient(180deg,#ffffffb8,#ffffff47),#dff7f2;color:var(--accent);box-shadow:0 12px 30px #128c7e21}.drop-empty-state strong{color:var(--ink);font-size:1rem}.drop-empty-state small{color:var(--muted);font-weight:700}.result-toolbar{display:contents}.result-toolbar .secondary-button{width:100%;min-height:46px}.background-options{display:grid;grid-template-columns:repeat(3,minmax(0,1fr));gap:6px;padding:4px;border:1px solid var(--line);border-radius:var(--radius);background:#f5f7f8}.background-options button{min-height:36px;border-radius:6px;background:transparent;color:var(--muted);font-size:.84rem;font-weight:800;cursor:pointer}.background-options button.active{background:#fff;color:var(--ink);box-shadow:0 4px 14px #171b1f14}.background-options button:disabled{cursor:not-allowed;opacity:.56}.spin{animation:spin .9s linear infinite}@keyframes spin{to{transform:rotate(360deg)}}@keyframes coffee-wiggle{0%,78%,to{transform:rotate(0) translateY(0)}82%{transform:rotate(-10deg) translateY(-1px)}86%{transform:rotate(9deg) translateY(0)}90%{transform:rotate(-6deg) translateY(-1px)}94%{transform:rotate(4deg) translateY(0)}}@media(max-width:760px){body{overflow:auto}.app-shell{width:min(100% - 20px,960px);min-height:auto;padding-top:16px}.tool-card{padding:16px;gap:18px}.topbar{flex-direction:row;align-items:center}.nav-links{width:auto;flex-wrap:nowrap}.original-toolbar,.preview-grid,.result-toolbar{grid-template-columns:1fr}.upload-button,.primary-button,.secondary-button{width:100%}.preview-grid{gap:22px}.preview-card,.result-card{grid-template-rows:auto;row-gap:10px}.preview-surface{height:auto;min-height:240px}.preview-surface img{max-height:220px}}