/* 基礎變數 */
:root{--c-bg:#f6f8fb;--c-panel:#ffffff;--c-ink:#172033;--c-muted:#687386;--c-line:#dde5ef;--c-primary:#1f7ae0;--c-primary-dark:#1456a3;--c-success:#15a36a;--c-danger:#d84646;--c-warning:#f2b84b;--c-soft:#edf5ff;--c-shadow:0 18px 45px rgba(23,32,51,.09);--g-primary:linear-gradient(135deg,#1f7ae0 0%,#26b7c8 100%);--g-hero:linear-gradient(135deg,#0f2847 0%,#165c8c 52%,#20b58f 100%);}
*{box-sizing:border-box;}
body{min-height:100vh;background:var(--c-bg);color:var(--c-ink);font-family:"Noto Sans TC","Microsoft JhengHei",Arial,sans-serif;}
button,input,select{font:inherit;}
.app-nav{background:var(--c-panel);border-bottom:1px solid var(--c-line);}
.navbar-brand{display:flex;align-items:center;gap:.65rem;font-weight:800;color:var(--c-ink);}
.navbar-brand i{color:var(--c-primary);}
.nav-note{align-items:center;gap:.5rem;color:var(--c-muted);font-size:.92rem;}
.app-shell{padding-top:28px;padding-bottom:44px;}
.hero-panel{display:grid;grid-template-columns:minmax(0,1fr) 360px;gap:24px;align-items:center;margin-bottom:24px;padding:30px;border-radius:18px;background:var(--g-hero);box-shadow:var(--c-shadow);color:#fff;overflow:hidden;}
.hero-copy h1{max-width:760px;margin:0 0 12px;font-size:clamp(1.8rem,3vw,3rem);font-weight:900;line-height:1.15;letter-spacing:0;}
.hero-copy p{margin:0;color:rgba(255,255,255,.82);line-height:1.75;}
.eyebrow{margin:0 0 8px!important;color:#a7f5ff!important;font-size:.82rem;font-weight:800;text-transform:uppercase;letter-spacing:.08em;}
.hero-steps{display:grid;grid-template-columns:1fr;gap:12px;}
.hero-steps div{display:flex;align-items:center;gap:12px;padding:14px 16px;border:1px solid rgba(255,255,255,.24);border-radius:14px;background:rgba(255,255,255,.12);backdrop-filter:blur(6px);}
.hero-steps b{display:grid;place-items:center;width:34px;height:34px;border-radius:50%;background:#fff;color:var(--c-primary);}
.hero-steps span{font-weight:800;}
.tool-panel{margin-bottom:24px;padding:22px;border:1px solid var(--c-line);border-radius:18px;background:var(--c-panel);box-shadow:0 10px 30px rgba(23,32,51,.05);}
.section-title{display:flex;align-items:flex-start;gap:12px;margin-bottom:18px;}
.section-title>i{display:grid;place-items:center;width:38px;height:38px;border-radius:12px;background:var(--c-soft);color:var(--c-primary);font-size:1.05rem;}
.section-title h2{margin:0 0 3px;font-size:1.12rem;font-weight:900;}
.section-title p{margin:0;color:var(--c-muted);font-size:.92rem;line-height:1.5;}
.drop-zone{position:relative;display:grid;place-items:center;gap:8px;min-height:178px;padding:22px;border:2px dashed #b9c8da;border-radius:16px;background:#f9fbff;text-align:center;cursor:pointer;transition:.2s;}
.drop-zone:hover,.drop-zone.is-drag{border-color:var(--c-primary);background:var(--c-soft);transform:translateY(-1px);}
.drop-zone input{position:absolute;inset:0;width:100%;height:100%;opacity:0;cursor:pointer;}
.drop-zone i{font-size:2.3rem;color:var(--c-primary);}
.drop-zone strong{font-size:1.05rem;}
.drop-zone span{color:var(--c-muted);font-size:.9rem;}
.upload-list-head{display:flex;align-items:center;justify-content:space-between;margin:16px 0 10px;font-weight:800;}
.file-list{display:grid;gap:10px;max-height:340px;overflow:auto;}
.file-item{display:grid;grid-template-columns:54px minmax(0,1fr) auto;gap:10px;align-items:center;padding:8px;border:1px solid var(--c-line);border-radius:12px;background:#fff;}
.file-item.active{border-color:var(--c-primary);background:var(--c-soft);}
.file-thumb{width:54px;height:54px;border-radius:10px;object-fit:cover;background:#dfe8f2;}
.file-info strong{display:block;overflow:hidden;text-overflow:ellipsis;white-space:nowrap;font-size:.92rem;}
.file-info span{display:block;color:var(--c-muted);font-size:.8rem;}
.icon-btn{display:grid;place-items:center;width:34px;height:34px;border:0;border-radius:10px;background:#eef3f8;color:var(--c-muted);}
.icon-btn:hover{background:#ffecec;color:var(--c-danger);}
.mode-grid,.size-options{display:grid;grid-template-columns:1fr 1fr;gap:10px;}
.mode-btn,.size-btn{min-height:58px;border:1px solid var(--c-line);border-radius:13px;background:#fff;color:var(--c-ink);font-weight:900;transition:.2s;}
.mode-btn span,.size-btn span{display:block;margin-top:2px;color:var(--c-muted);font-size:.78rem;font-weight:700;}
.mode-btn:hover,.size-btn:hover,.mode-btn.active,.size-btn.active{border-color:var(--c-primary);background:var(--c-soft);color:var(--c-primary-dark);}
.custom-grid{display:none;margin-top:14px;}
.option-group{margin-bottom:18px;}
.form-label{margin-bottom:7px;color:var(--c-muted);font-weight:800;font-size:.9rem;}
.form-control,.form-select{border-color:var(--c-line);border-radius:12px;}
.option-row{display:flex;align-items:center;justify-content:space-between;gap:14px;padding:14px 0;border-top:1px solid var(--c-line);}
.option-row strong,.option-row span{display:block;}
.option-row span{color:var(--c-muted);font-size:.84rem;}
.form-check-input:checked{background-color:var(--c-primary);border-color:var(--c-primary);}
.guide-list{display:grid;gap:12px;margin:0;padding:0;list-style:none;counter-reset:guide;}
.guide-list li{display:grid;grid-template-columns:32px 1fr;gap:10px;align-items:start;counter-increment:guide;}
.guide-list li:before{content:counter(guide);display:grid;place-items:center;width:28px;height:28px;border-radius:50%;background:#eef7f3;color:var(--c-success);font-weight:900;}
.guide-list b,.guide-list span{display:block;}
.guide-list span{color:var(--c-muted);font-size:.9rem;line-height:1.55;}
.action-bar{display:grid;grid-template-columns:1fr 1fr;gap:10px;margin-bottom:16px;}
.btn{border-radius:12px;font-weight:800;}
.result-grid{display:grid;grid-template-columns:repeat(2,minmax(0,1fr));gap:12px;max-height:735px;overflow:auto;padding-right:2px;}
.piece-card{border:1px solid var(--c-line);border-radius:14px;background:#fff;overflow:hidden;}
.piece-preview{display:grid;place-items:center;aspect-ratio:1/1;background-color:#f4f7fb;background-image:linear-gradient(45deg,#dfe7f0 25%,transparent 25%),linear-gradient(-45deg,#dfe7f0 25%,transparent 25%),linear-gradient(45deg,transparent 75%,#dfe7f0 75%),linear-gradient(-45deg,transparent 75%,#dfe7f0 75%);background-size:18px 18px;background-position:0 0,0 9px,9px -9px,-9px 0;}
.piece-preview img{max-width:100%;max-height:100%;object-fit:contain;}
.piece-meta{display:flex;align-items:center;justify-content:space-between;gap:8px;padding:9px;}
.piece-meta span{overflow:hidden;text-overflow:ellipsis;white-space:nowrap;color:var(--c-muted);font-size:.78rem;}
.piece-meta button{flex:0 0 auto;}
.empty-state{display:grid;place-items:center;min-height:120px;border:1px dashed var(--c-line);border-radius:14px;color:var(--c-muted);text-align:center;}
.app-footer{padding:18px 0;border-top:1px solid var(--c-line);background:#fff;color:var(--c-muted);font-size:.9rem;}
.app-footer .container{display:flex;justify-content:space-between;gap:14px;}
@media (max-width:991.98px){.hero-panel{grid-template-columns:1fr;}.hero-steps{grid-template-columns:repeat(3,1fr);}.result-grid{grid-template-columns:repeat(3,minmax(0,1fr));max-height:none;}}
@media (max-width:575.98px){.app-shell{padding-top:16px;}.hero-panel{padding:22px;border-radius:14px;}.hero-steps{grid-template-columns:1fr;}.tool-panel{padding:18px;border-radius:14px;}.mode-grid,.size-options,.action-bar{grid-template-columns:1fr;}.result-grid{grid-template-columns:repeat(2,minmax(0,1fr));}.app-footer .container{display:grid;}}