style-editor.css

/* Main column width */
.edit-post-visual-editor.edit-post-visual-editor .editor-post-title__block,
.edit-post-visual-editor.edit-post-visual-editor .editor-default-block-appender,
.edit-post-visual-editor.edit-post-visual-editor .editor-block-list__block {
    max-width: 900px;
}

/* Main column width */
.wp-block {
    max-width: 900px;
}

/* Editor styles */
.editor-block-list__block, .editor-block-list__block p {
    color: #7a7c84;
	font-family: Lato, sans-serif !important;
}
.edit-post-visual-editor .editor-post-title__block .editor-post-title__input,
.edit-post-visual-editor .editor-block-list__block h1,
.edit-post-visual-editor .editor-block-list__block h2,
.edit-post-visual-editor .editor-block-list__block h3,
.edit-post-visual-editor .editor-block-list__block h4,
.edit-post-visual-editor .editor-block-list__block h5,
.edit-post-visual-editor .editor-block-list__block h6 {
    color: #2c313f;
    font-family: Poppins, sans-serif;
    font-weight: bold;
}
.edit-post-visual-editor .editor-post-title__block .editor-post-title__input,
.edit-post-visual-editor .editor-block-list__block h1 {
    font-size: 49px;
    font-size: 3.0625rem;
    line-height: 1.2245;
}
.edit-post-visual-editor .editor-block-list__block h2 {
    font-size: 40px;
    font-size: 2.5rem;
    line-height: 1.125;
}
.edit-post-visual-editor .editor-block-list__block h3 {
    font-size: 32px;
    font-size: 2rem;
    line-height: 1.1719;
}
.edit-post-visual-editor .editor-block-list__block h4 {
    font-size: 25px;
    font-size: 1.5625rem;
    line-height: 1.2;
}
.edit-post-visual-editor .editor-block-list__block h5 {
    font-size: 20px;
    font-size: 1.25rem;
    line-height: 1.5;
}
.edit-post-visual-editor .editor-block-list__block h6 {
    font-size: 16px;
    font-size: 1rem;
    line-height: 1.40625;
}

.edit-post-visual-editor .editor-block-list__block[data-align=full] {
    max-width: none !important;
}
.edit-post-visual-editor .editor-block-list__block[data-align=wide] {
    max-width: 1100px !important;
}