:root{color:#18181b;background:#f4f1ea;font-family:Arial,PingFang SC,Microsoft YaHei,sans-serif}*{box-sizing:border-box}body{margin:0}button,input{font:inherit}.app-shell{grid-template-columns:minmax(360px,520px) 1fr;gap:0;min-height:100vh;display:grid}.tool-panel{background:#fffdf8;border-right:1px solid #d6d3cc;flex-direction:column;gap:18px;padding:40px;display:flex}.panel-header{gap:8px;display:grid}.eyebrow{color:#6b7280;letter-spacing:.12em;text-transform:uppercase;margin:0;font-size:12px;font-weight:700}h1{letter-spacing:0;margin:0;font-size:32px;font-weight:800}.converter-form{gap:18px;display:grid}.upload-box{cursor:pointer;text-align:center;background:#fafafa;border:1px dashed #a1a1aa;place-items:center;min-height:132px;padding:22px;transition:border-color .16s,background .16s;display:grid}.upload-box:hover{background:#fff;border-color:#18181b}.upload-box input{display:none}.upload-title{overflow-wrap:anywhere;max-width:100%;font-size:18px;font-weight:800}.upload-meta{color:#71717a;font-size:13px}.field-group{gap:10px;display:grid}.field-label{color:#52525b;font-size:13px;font-weight:700}.profile-grid{grid-template-columns:repeat(2,minmax(0,1fr));gap:10px;display:grid}.profile-card{cursor:pointer;text-align:left;background:#fff;border:1px solid #d4d4d8;gap:6px;min-height:76px;padding:14px;transition:border-color .16s,background .16s,color .16s;display:grid}.profile-card span{font-weight:800}.profile-card small{color:#71717a;font-size:12px}.profile-card.active{color:#fff;background:#18181b;border-color:#18181b}.profile-card.active small{color:#d4d4d8}.duration-row{background:#fff;border:1px solid #e4e4e7;gap:12px;padding:14px;display:grid}.duration-row span{justify-content:space-between;align-items:center;gap:12px;display:flex}.duration-row small{color:#71717a;font-size:12px}.duration-row input{accent-color:#18181b;width:100%}.primary-button,.download-button{color:#fff;cursor:pointer;background:#18181b;border:1px solid #18181b;justify-content:center;align-items:center;min-height:44px;font-weight:800;text-decoration:none;transition:opacity .16s,transform .16s;display:inline-flex}.primary-button:hover,.download-button:hover{transform:translateY(-1px)}.primary-button:disabled{cursor:not-allowed;opacity:.45;transform:none}.progress-track{background:#fff;border:1px solid #d4d4d8;height:8px;overflow:hidden}.progress-track span{background:#18181b;height:100%;transition:width .16s;display:block}.message{color:#3f3f46;background:#fff;border:1px solid #d4d4d8;padding:12px 14px;font-size:14px}.message.error{color:#be123c;background:#fff1f2;border-color:#fecaca}.result-card{background:#fff;border:1px solid #d4d4d8;grid-template-columns:1fr 140px;align-items:center;gap:14px;padding:14px;display:grid}.result-card div{gap:4px;min-width:0;display:grid}.result-card strong{overflow-wrap:anywhere;font-size:14px}.result-card span{color:#71717a;font-size:12px}.preview-panel{background:linear-gradient(135deg,#18181b14,#fff0),#ece7db;place-items:center;padding:36px;display:grid}.phone-frame{aspect-ratio:9/16;background:#111827;border:10px solid #18181b;border-radius:34px;place-items:center;width:min(62vw,430px);display:grid;overflow:hidden;box-shadow:0 26px 70px #18181b38}.phone-frame img{object-fit:cover;width:100%;height:100%}.empty-preview{color:#f4f4f5;text-align:center;place-items:center;gap:8px;display:grid}.empty-preview span{color:#a1a1aa;font-size:13px;font-weight:700}.empty-preview strong{letter-spacing:0;font-size:28px}@media (max-width:900px){.app-shell{grid-template-columns:1fr}.tool-panel{border-right:0;padding:24px}.preview-panel{min-height:560px;padding:24px}.phone-frame{width:min(86vw,360px)}}