:root {
    --white: #fff;
    --primary: #007bff;
    --secondary: #6c757d;
    --success: #28a745;
    --danger: #dc3545;
    --warning: #ffc107;
    --info: #17a2b8;
    --dark: #343a40;
    --light: #f8f9fa;
}

/* color */

.text-white {color: var(--white);}
.text-primary {color: var(--primary);}
.text-secondary {color: var(--secondary);}
.text-success {color: var(--success);}
.text-danger {color: var(--danger);}
.text-warning {color: var(--warning);}
.text-info {color: var(--info);}
.text-dark {color: var(--dark);}
.text-light {color: var(--light);}

/* background */

.bg-primary {background-color: var(--primary);}
.bg-secondary {background-color: var(--secondary);}
.bg-success {background-color: var(--success);}
.bg-danger {background-color: var(--danger);}
.bg-warning {background-color: var(--warning);}
.bg-info {background-color: var(--info);}
.bg-dark {background-color: var(--dark);}
.bg-light {background-color: var(--light);}

/* buttons */

.btn {
    cursor: pointer;
    display: inline-block;
    padding: 10px 30px;
    border: none;
    border-radius: 5px;
    font-size: 1.6rem;
}

.btn:hover {
    opacity: 0.9;
}

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

.btn-secondary {
    color: var(--white);
    background-color: var(--secondary);
}

.btn-success {
    color: var(--white);
    background-color: var(--success);
}

.btn-danger {
    color: var(--white);
    background-color: var(--danger);
}

.btn-warning {
    color: var(--white);
    background-color: var(--warning);
}

.btn-dark {
    color: var(--white);
    background-color: var(--dark);
}

.btn-outline {
    background: transparent;
    border: 1px solid var(--white);
    color: var(--white);
}

.btn-outline-primary {
    background: transparent;
    border: 1px solid var(--primary);
    color: var(--dark);
}

.btn-outline-primary:hover {
    background-color: var(--primary);
    border: 1px solid var(--primary);
    color: var(--white);
}

/* flex */

.flex-items {
    display: flex;
    justify-content: center;
    text-align: center;
    height: 100%;
}

.flex-items > div {
    padding: 20px;
    flex-basis: 100%;
}

/* flex columns */
.flex-columns.flex-reverse .row{
    flex-direction: row-reverse;
}

.flex-columns .row {
    display: flex;
    flex-direction: row;
    flex-wrap: wrap;
    width: 100%;
}

.flex-columns .column {
    flex: 1;
}

.flex-columns.article .column:nth-child(odd) {
    flex: 1;
}

.flex-columns.article .column:nth-child(even) {
    flex: 3;
}

.flex-columns .column .column-1, .flex-columns .column .column-2 {
    height: 100%;
}

.flex-columns .column .column-2 {
    display: flex;
    flex-direction: column;
    align-items: flex-start;
    justify-content: center;
    padding: 3rem;
}

.flex-columns img {
    width: 100%;
    height: 100%;
}

/* flex-grid */

.flex-grid .row {
    display: flex;
    flex-wrap: wrap;
    padding: 0 .4rem;
}

.flex-grid .column {
    flex: 25%;
    padding: 0 .4rem;
}


/* section */

.section-header {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-align: center;
    padding: 3rem;
}

.section-header h2 {
    font-size: 4rem;
    font-weight: bold;
    margin: 2rem 0;
}

.section-padding {
    padding: 5rem 2rem 10rem;
}

@media (max-width: 576px) {
    .flex-items {
        flex-direction: column;
    }
    
    .flex-columns .column {
        flex: 100% !important;
    }
    
    .flex-grid .column {
        flex: 50%;
    }
}