:root {
    --bg-light: #f8f9fa;
    --bg-dark: #212529;
    --text-light: #212529;
    --text-dark: #f8f9fa;
    --card-bg-light: #ffffff;
    --card-bg-dark: #343a40;
    --primary: #007bff;
    --primary-hover: #0056b3;
}

body {
    transition: background-color 0.3s, color 0.3s;
}

body.light-mode {
    background-color: var(--bg-light);
    color: var(--text-light);
}

body.dark-mode {
    background-color: var(--bg-dark);
    color: var(--text-dark);
}

.card {
    transition: background-color 0.3s;
}

body.light-mode .card {
    background-color: var(--card-bg-light);
}

body.dark-mode .card {
    background-color: var(--card-bg-dark);
}

.btn-primary {
    background-color: var(--primary);
    border-color: var(--primary);
}

.btn-primary:hover {
    background-color: var(--primary-hover);
    border-color: var(--primary-hover);
}

.form-control {
    transition: background-color 0.3s, color 0.3s;
}

body.dark-mode .form-control {
    background-color: #495057;
    color: #f8f9fa;
    border-color: #6c757d;
}

.mode-toggle {
    position: fixed;
    top: 20px;
    right: 20px;
    z-index: 1000;
}