* { box-sizing: border-box; margin: 0; padding: 0; }
        body { 
            font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
            background: linear-gradient(
                135deg,
                #415d8b 0%,    /* medium-dark blue corner */
                #415d8b 25%,   /* more gradual dark area */
                #50a7ee 50%,   /* light blue center */
                #415d8b 75%,   /* gradual return to dark */
                #415d8b 100%   /* dark blue corner */
                );



            min-height: 100vh;
            display: flex;
            align-items: center;
            justify-content: center;
            padding: 1rem;
        }
        .form-container {
            background: white;
            padding: 2.5rem;
            border-radius: 16px;
            box-shadow: 0 20px 25px -5px rgba(0, 0, 0, 0.1);
            width: 100%;
            max-width: 450px;
        }
        .form-header { text-align: center; margin-bottom: 2rem; }
        .form-title { font-size: 1.875rem; font-weight: bold; color: #1f2937; margin-bottom: 0.5rem; }
        .form-subtitle { color: #6b7280; font-size: 0.875rem; }
        .form-group { margin-bottom: 1rem; }
        .form-label { display: block; font-weight: 500; color: #374151; margin-bottom: 0.5rem; }
        .form-input {
            width: 100%;
            padding: 0.75rem;
            border: 2px solid #e5e7eb;
            border-radius: 8px;
            font-size: 1rem;
            transition: all 0.2s;
            background: #f9fafb;
        }
        .form-input:focus {
            outline: none;
            border-color: #4caac9;
            background: white;
            box-shadow: 0 0 0 3px rgba(76, 170, 201, 0.1);
        }
        .btn {
            width: 100%;
            background: linear-gradient(135deg, #4caac9 0%, #3d98b3 100%);
            color: white;
            padding: 0.875rem;
            border: none;
            border-radius: 8px;
            font-size: 1rem;
            font-weight: 500;
            cursor: pointer;
            transition: all 0.2s;
        }
        .btn:hover { transform: translateY(-1px); box-shadow: 0 10px 15px -3px rgba(0, 0, 0, 0.1); }
        .auth-link { text-align: center; margin-top: 1.5rem; }
        .auth-link a { color: #4caac9; text-decoration: none; font-weight: 500; }
        .flash-error { background: #fef2f2; color: #dc2626; padding: 0.75rem; border-radius: 8px; border: 1px solid #fecaca; font-size: 0.875rem; margin-bottom: 1rem; }
        .field-help { font-size: 0.75rem; color: #6b7280; margin-top: 0.25rem; }

        /* Field validation styles */
.form-input.invalid {
    border-color: #ef4444;
    background-color: #fef2f2;
}

.field-error {
    color: #dc2626;
    font-size: 0.75rem;
    margin-top: 0.25rem;
    display: block;
}

/* Loading state for buttons */
.btn.loading {
    opacity: 0.7;
    cursor: not-allowed;
}

/* Checkbox styling */
.form-group-checkbox {
    margin-bottom: 1.25rem;
}

.checkbox-label {
    display: flex;
    align-items: center;
    gap: 0.5rem;
    cursor: pointer;
    font-size: 0.875rem;
    color: #4b5563;
    user-select: none;
}

.checkbox-label input[type="checkbox"] {
    width: 18px;
    height: 18px;
    cursor: pointer;
    accent-color: #4caac9;
}

.checkbox-label:hover {
    color: #1f2937;
}

/* Password strength meter */
.password-strength-meter {
    margin-top: 0.5rem;
    margin-bottom: 0.5rem;
}

.strength-bar {
    height: 4px;
    background: #e5e7eb;
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 0.25rem;
}

.strength-fill {
    height: 100%;
    width: 0%;
    transition: width 0.3s ease, background 0.3s ease;
    border-radius: 2px;
}

.strength-text {
    font-size: 0.75rem;
    font-weight: 500;
    color: #6b7280;
}

.strength-fill[data-strength="weak"] {
    background: #ef4444;
}

.strength-fill[data-strength="fair"] {
    background: #f59e0b;
}

.strength-fill[data-strength="good"] {
    background: #10b981;
}

.strength-fill[data-strength="strong"] {
    background: #22c55e;
}