:root{--bg:#0b0f14;--bg-card:#131a22;--bg-inset:#0e141b;--border:#243040;--border-strong:#33445a;--text:#e8eef4;--text-dim:#8fa0b0;--accent:#45b8ff;--accent-strong:#1e9bef;--accent-contrast:#06121c;--ok:#3ddc97;--warn:#f5b742;--danger:#ff6b6b;--info:#7aa5ff;--muted:#8fa0b0;--radius:14px;--radius-sm:8px;--font-sans:-apple-system,BlinkMacSystemFont,"PingFang SC","Hiragino Sans GB","Microsoft YaHei","Segoe UI",Roboto,sans-serif;--font-mono:ui-monospace,SFMono-Regular,"SF Mono",Menlo,Consolas,"Liberation Mono",monospace}*{box-sizing:border-box}body,html{margin:0;padding:0}html{color-scheme:dark}body{min-height:100vh;background-color:var(--bg);background-image:radial-gradient(900px 500px at 50% -180px,#16222e 0,var(--bg) 70%);color:var(--text);font-family:var(--font-sans);font-size:16px;line-height:1.6;-webkit-font-smoothing:antialiased}a{color:var(--accent);text-decoration:none}a:hover{text-decoration:underline}button{font-family:inherit}:focus-visible{outline:2px solid var(--accent);outline-offset:2px}.screen-center{min-height:100vh;display:flex;flex-direction:column;gap:16px;padding:24px;text-align:center}.btn,.screen-center{align-items:center;justify-content:center}.btn{display:inline-flex;min-height:44px;padding:10px 22px;border:1px solid var(--border-strong);border-radius:var(--radius-sm);background:var(--bg-card);color:var(--text);font-size:15px;font-weight:600;cursor:pointer;transition:background-color .15s ease,border-color .15s ease,transform .05s ease}.btn:hover{border-color:var(--accent)}.btn:active{transform:scale(.98)}.btn-primary{background:var(--accent);border-color:var(--accent);color:var(--accent-contrast)}.btn-primary:hover{background:var(--accent-strong);border-color:var(--accent-strong)}.hint{color:var(--text-dim);font-size:14px;margin:0}.spinner{width:28px;height:28px;border:3px solid var(--border);border-top-color:var(--accent);border-radius:50%;animation:spin .8s linear infinite}@keyframes spin{to{transform:rotate(1turn)}}