:root { color-scheme: light dark; font-family: system-ui, -apple-system, "Segoe UI", sans-serif; }
body { margin: 0; min-height: 100vh; display: grid; place-items: center; background: #f6f1ea; color: #1f1a17; }
.pair { width: min(28rem, 92vw); padding: 2rem; background: #fff; border-radius: 1rem; box-shadow: 0 8px 30px rgb(0 0 0 / 0.08); }
.pair h1 { margin: 0 0 0.5rem; font-size: 1.6rem; }
.pair p { line-height: 1.5; }
.pair label { display: block; font-weight: 600; margin: 1rem 0 0.4rem; }
.pair input { width: 100%; box-sizing: border-box; font-size: 2rem; letter-spacing: 0.3em; text-transform: uppercase; padding: 0.6rem 0.8rem; border: 2px solid #c8b8a6; border-radius: 0.6rem; }
.pair input:focus-visible { outline: 3px solid #2f6f4e; outline-offset: 2px; }
.pair button { margin-top: 1.2rem; width: 100%; min-height: 3.2rem; font-size: 1.2rem; font-weight: 700; color: #fff; background: #3b2a20; border: 0; border-radius: 0.6rem; cursor: pointer; }
.pair__error { color: #b3261e; font-weight: 600; }
@media (prefers-color-scheme: dark) { body { background: #14110f; color: #f5efe8; } .pair { background: #1f1a17; } }