/* Trang web công khai (đăng ký, tải ứng dụng). Không dùng CSS nội tuyến: máy chủ cấm style nội tuyến. */
:root { color-scheme: light dark; --bg: #f4f6f8; --card: #ffffff; --fg: #1d2630; --muted: #5d6b78; --line: #d9dfe5; --accent: #0a7d4f; --bad: #b3261e; --ok: #1b6e3a; --soft: #eef6f1; }
@media (prefers-color-scheme: dark) { :root:not([data-theme="light"]) { --bg: #14181d; --card: #1e242b; --fg: #e8ecef; --muted: #9aa5b1; --line: #35404b; --accent: #3ccf8e; --bad: #ff8a80; --ok: #7ddc8a; --soft: #1b2a22; } }
:root[data-theme="dark"] { color-scheme: dark; --bg: #14181d; --card: #1e242b; --fg: #e8ecef; --muted: #9aa5b1; --line: #35404b; --accent: #3ccf8e; --bad: #ff8a80; --ok: #7ddc8a; --soft: #1b2a22; }
* { box-sizing: border-box; }
body { margin: 0; background: var(--bg); background-color: var(--bg); color: var(--fg); font: 16px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, Arial, sans-serif; padding: 0 16px 48px; }
[hidden] { display: none !important; }
header.top { max-width: 880px; margin: 0 auto; padding: 22px 0 8px; display: flex; align-items: center; justify-content: space-between; gap: 12px; flex-wrap: wrap; }
header.top a.brand { color: var(--fg); text-decoration: none; font-weight: 700; font-size: 18px; }
nav.menu a { color: var(--accent); text-decoration: none; margin-left: 14px; font-weight: 600; }
main { max-width: 880px; margin: 0 auto; }
h1 { font-size: 26px; margin: 18px 0 6px; }
h2 { font-size: 19px; margin: 0 0 10px; }
h3 { font-size: 16px; margin: 16px 0 6px; }
.lead { color: var(--muted); margin: 0 0 14px; }
.card { background: var(--card); border: 1px solid var(--line); border-radius: 14px; padding: 18px; margin: 14px 0; }
.grid2 { display: grid; grid-template-columns: 1fr 1fr; gap: 14px; }
@media (max-width: 680px) { .grid2 { grid-template-columns: 1fr; } }
label { display: block; font-size: 14px; color: var(--muted); margin: 12px 0 4px; }
input[type="text"], input[type="password"] { width: 100%; font: inherit; color: var(--fg); background: var(--bg); border: 1px solid var(--line); border-radius: 10px; padding: 11px 12px; }
input:focus { outline: 2px solid var(--accent); outline-offset: 1px; }
button, .btn { font: inherit; border: 0; border-radius: 10px; padding: 11px 18px; cursor: pointer; background: var(--accent); color: #fff; font-weight: 600; text-decoration: none; display: inline-block; }
button:disabled, .btn.disabled { background: var(--line); color: var(--muted); cursor: not-allowed; }
button.ghost { background: transparent; color: var(--accent); border: 1px solid var(--line); }
.row { display: flex; gap: 10px; align-items: center; flex-wrap: wrap; margin-top: 14px; }
.msg { min-height: 1.4em; margin: 10px 0 0; }
.err { color: var(--bad); }
.ok { color: var(--ok); }
.note { font-size: 14px; color: var(--muted); }
.soft { background: var(--soft); border-radius: 12px; padding: 12px 14px; }
ul.tips { padding-left: 20px; margin: 8px 0; }
ul.tips li { margin: 6px 0; }
table.cmp { width: 100%; border-collapse: collapse; font-size: 15px; }
table.cmp th, table.cmp td { text-align: left; padding: 9px 8px; border-bottom: 1px solid var(--line); vertical-align: top; }
table.cmp th { color: var(--muted); font-weight: 600; }
code { font: 14px Consolas, monospace; background: var(--bg); border: 1px solid var(--line); border-radius: 6px; padding: 1px 6px; word-break: break-all; }
footer { max-width: 880px; margin: 26px auto 0; color: var(--muted); font-size: 14px; }