:root {
    --bg: #f7f7f8;
    --card: #ffffff;
    --text: #1a1a1a;
    --muted: #666;
    --accent: #1d4ed8;
    --accent-hover: #1e40af;
    --border: #e5e7eb;
    --error-bg: #fef2f2;
    --error-border: #fecaca;
    --error-text: #991b1b;
    --warn-bg: #fffbeb;
    --warn-border: #fde68a;
    --warn-text: #92400e;
}
* { box-sizing: border-box; }
body {
    margin: 0;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    background: var(--bg);
    color: var(--text);
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}
.site-header {
    background: var(--card);
    border-bottom: 1px solid var(--border);
    padding: 1rem 1.5rem;
}
.site-header a {
    color: var(--text);
    text-decoration: none;
    font-weight: 600;
    font-size: 1.1rem;
}
.container {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 2rem 1rem;
}
.card {
    background: var(--card);
    border: 1px solid var(--border);
    border-radius: 8px;
    padding: 2rem;
    width: 100%;
    max-width: 420px;
    box-shadow: 0 1px 3px rgba(0,0,0,0.04);
}
.card h1 {
    margin: 0 0 1.5rem;
    font-size: 1.5rem;
    font-weight: 600;
}
form { display: flex; flex-direction: column; gap: 1rem; }
label {
    display: flex;
    flex-direction: column;
    gap: 0.35rem;
    font-size: 0.9rem;
    color: var(--muted);
}
input[type="email"], input[type="password"], input[type="text"] {
    padding: 0.6rem 0.75rem;
    border: 1px solid var(--border);
    border-radius: 6px;
    font-size: 1rem;
    color: var(--text);
    background: #fff;
}
input:focus {
    outline: 2px solid var(--accent);
    outline-offset: -1px;
    border-color: var(--accent);
}
button {
    padding: 0.7rem 1rem;
    background: var(--accent);
    color: #fff;
    border: none;
    border-radius: 6px;
    font-size: 1rem;
    font-weight: 500;
    cursor: pointer;
}
button:hover { background: var(--accent-hover); }
.alert {
    padding: 0.75rem 1rem;
    border-radius: 6px;
    border: 1px solid;
    font-size: 0.9rem;
    margin-bottom: 1rem;
}
.alert.error { background: var(--error-bg); border-color: var(--error-border); color: var(--error-text); }
.alert.warn  { background: var(--warn-bg);  border-color: var(--warn-border);  color: var(--warn-text); }
.muted { color: var(--muted); font-size: 0.85rem; }
.site-footer {
    text-align: center;
    padding: 1.5rem;
    color: var(--muted);
    font-size: 0.85rem;
}
.links { display: flex; justify-content: space-between; margin-top: 0.5rem; }
.links a { color: var(--accent); text-decoration: none; font-size: 0.9rem; }
.links a:hover { text-decoration: underline; }