:root {
  --bg: #f4f5f7; --surface: #fff; --text: #16181d; --muted: #5c6470; --border: #d9dde3;
  --accent: #2459d6; --accent-text: #fff; --danger: #c62828; --danger-bg: #fdecea;
  color-scheme: light;
}
@media (prefers-color-scheme: dark) {
  :root:not([data-theme="light"]) {
    --bg: #0e1014; --surface: #161920; --text: #e7e9ee; --muted: #a3abb7; --border: #2f3540;
    --accent: #7aa2ff; --accent-text: #0e1014; --danger: #ff7b72; --danger-bg: #3a1716;
    color-scheme: dark;
  }
}
:root[data-theme="dark"] {
  --bg: #0e1014; --surface: #161920; --text: #e7e9ee; --muted: #a3abb7; --border: #2f3540;
  --accent: #7aa2ff; --accent-text: #0e1014; --danger: #ff7b72; --danger-bg: #3a1716;
  color-scheme: dark;
}
* { box-sizing: border-box; }
body {
  margin: 0; min-height: 100vh; display: grid; place-items: center; padding: 16px;
  background: var(--bg); color: var(--text);
  font: 15px/1.5 system-ui, -apple-system, "Segoe UI", Roboto, "Noto Sans", sans-serif;
}
.box {
  width: 100%; max-width: 360px; background: var(--surface); border: 1px solid var(--border);
  border-radius: 14px; padding: 26px 22px;
}
h1 { margin: 0; font-size: 20px; letter-spacing: -.01em; }
.sub { margin: 4px 0 20px; color: var(--muted); font-size: 14px; }
label { display: block; font-size: 13px; font-weight: 600; color: var(--muted); margin-bottom: 6px; }
input {
  width: 100%; font: inherit; font-size: 16px; padding: 10px 12px; border-radius: 10px;
  border: 1px solid var(--border); background: var(--bg); color: var(--text);
}
input:focus-visible, button:focus-visible { outline: 2px solid var(--accent); outline-offset: 2px; }
button {
  margin-top: 14px; width: 100%; font: inherit; font-weight: 600; padding: 10px 12px; border: 0;
  border-radius: 10px; background: var(--accent); color: var(--accent-text); cursor: pointer;
}
.msg { margin: 10px 0 0; padding: 8px 10px; border-radius: 8px; background: var(--danger-bg); color: var(--danger); font-size: 14px; }