:root {
    --primary: #1e40af;          /* Corporate Deep Blue */
    --primary-hover: #1d4ed8;    /* Interactive Hover Blue */
    --primary-light: #eff6ff;    /* Soft Tint Blue */
    --ink: #0f172a;               /* Slate 900 for high-contrast typography */
    --muted: #64748b;             /* Slate 500 for secondary text */
    --line: #e2e8f0;              /* Crisp border gray */
    --bg: #f8fafc;                /* Off-white background for desktop contrast */
    --card-bg: #ffffff;
    --danger: #dc2626;
    --danger-bg: #fef2f2;
    --danger-border: #fecaca;
    --success: #15803d;
    --success-bg: #f0fdf4;
    --success-border: #bbf7d0;
    --radius: 12px;
}

* { box-sizing: border-box; }

/* ==========================================
   Standard Card Layout
   ========================================== */
body {
    margin: 0;
    background: var(--bg);
    color: var(--ink);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    display: flex;
    min-height: 100vh;
    align-items: center;
    justify-content: center;
    padding: 32px 16px;
    -webkit-font-smoothing: antialiased;
}

.card {
    width: 100%;
    max-width: 410px;
    background: var(--card-bg);
    border: 1px solid var(--line);
    border-radius: var(--radius);
    padding: 36px 32px;
    box-shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.05), 0 8px 10px -6px rgba(15, 23, 42, 0.03);
}

.brand {
    font-weight: 700;
    letter-spacing: 0.05em;
    color: var(--primary);
    font-size: 12px;
    text-transform: uppercase;
    margin-bottom: 6px;
}

h1 {
    font-size: 20px;
    font-weight: 700;
    letter-spacing: -0.01em;
    color: var(--ink);
    margin: 0 0 8px;
}

.sub {
    color: var(--muted);
    font-size: 13.5px;
    margin: 0 0 24px;
    line-height: 1.5;
}

input[type="email"] {
    width: 100%;
    padding: 9.5px 12px;
    border: 1px solid var(--line);
    border-radius: 6px;
    font-size: 14px;
    margin-bottom: 4px;
    background: #ffffff;
    color: var(--ink);
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

input:focus {
    outline: none;
    border-color: var(--primary);
    box-shadow: 0 0 0 3px rgba(30, 64, 175, 0.12);
}

button.primary {
    display: block;
    width: 100%;
    padding: 10px 16px;
    background: var(--primary);
    color: #ffffff;
    border: none;
    border-radius: 6px;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    text-align: center;
    text-decoration: none;
    transition: background-color 0.15s ease, transform 0.05s ease;
    margin-top: 10px;
}

button.primary:hover {
    background: var(--primary-hover);
}

button.primary:active {
    transform: translateY(1px);
}

button.primary:disabled {
    opacity: 0.6;
    cursor: not-allowed;
    transform: none;
}

.error {
    background: var(--danger-bg);
    border: 1px solid var(--danger-border);
    color: var(--danger);
    padding: 10px 12px;
    border-radius: 6px;
    font-size: 13px;
    margin-bottom: 20px;
}