:root{--bg:#101214;--panel:#191d22;--text:#f4f7f8;--sub:#9aa4aa;--teal:#4fbf9f;--blue:#2f80ff;--amber:#ffb347;--red:#ff6b6b;--border:#30363d}
*{box-sizing:border-box}body{margin:0;min-height:100vh;font-family:Arial,Helvetica,sans-serif;background:radial-gradient(circle at 20% 15%,rgba(79,191,159,.18),transparent 28%),radial-gradient(circle at 80% 70%,rgba(47,128,255,.16),transparent 30%),var(--bg);color:var(--text)}
.shell{width:min(760px,calc(100% - 32px));min-height:100vh;margin:0 auto;display:grid;place-items:center;padding:30px 0}.shell.wide{width:min(980px,calc(100% - 32px))}
.card{width:100%;background:rgba(25,29,34,.94);border:1px solid var(--border);border-radius:26px;padding:34px;box-shadow:0 24px 80px rgba(0,0,0,.4)}
.brand{display:inline-block;color:var(--teal);letter-spacing:.08em;text-transform:uppercase;font-weight:800;margin-bottom:14px}
h1{margin:0 0 14px;font-size:clamp(32px,5vw,54px);line-height:.98}p{color:var(--sub);font-size:18px;line-height:1.45}
label{display:block;color:var(--text);margin-bottom:8px;font-weight:700}
input[name="tablet_code"]{width:100%;height:56px;border:1px solid var(--teal);background:#242a30;color:var(--text);border-radius:16px;padding:0 16px;font-size:22px;outline:none}
button,.button-link{display:inline-flex;align-items:center;justify-content:center;min-height:54px;padding:0 22px;border:0;border-radius:16px;background:var(--teal);color:#101214;font-weight:800;font-size:16px;text-decoration:none;cursor:pointer;margin-top:14px}
.button-link.secondary{background:#242a30;color:var(--text);border:1px solid var(--blue);margin-left:10px}.code-form{margin-top:28px}.fine{font-size:14px;color:var(--sub);margin-top:22px}
.alert{background:rgba(255,107,107,.12);border:1px solid var(--red);border-radius:16px;padding:14px 16px;color:var(--text);margin:18px 0}
.drop{display:grid;place-items:center;min-height:230px;border:2px dashed var(--teal);border-radius:24px;background:rgba(79,191,159,.08);text-align:center;cursor:pointer}.drop input{display:none}.drop-title{display:block;font-size:30px;font-weight:800}.drop-sub{display:block;margin-top:8px;color:var(--sub)}
.file-list{margin-top:14px;color:var(--sub);font-size:15px}.file-list div{padding:8px 10px;border-bottom:1px solid var(--border)}
.steps{display:grid;grid-template-columns:repeat(4,1fr);gap:10px;margin-top:24px}.steps div{background:#242a30;border:1px solid var(--border);border-radius:16px;padding:14px;color:var(--sub)}.steps strong{color:var(--amber)}
@media(max-width:720px){.card{padding:24px}.steps{grid-template-columns:1fr 1fr}.button-link.secondary{margin-left:0}}