How to update css theme file in WordPress - css

Question

I am confused on where to edit WordPress themes. I am new to WordPress and have a custom theme which main style.css file just imports the style for this theme like this:
#import url('assets/stylesheets/app.css');
I read that it is recommended to make a new child theme, but I don't see the need for that in my case, since I would like to almost completely change the css of the theme, so there is no need to keep the original theme files. Since, I tried to modify the file 'assets/stylesheets/app.css' I couldn't see any changes in the browser. Can I edit the styles there, or I need to do it in the WP admin dashboard somewhere?
I would like to build my scripts with gulp, which I set up like this:
var gulp = require('gulp');
var sass = require('gulp-sass');
var include = require('gulp-include');
var watch = require('gulp-watch');
var batch = require('gulp-batch');
var sourcemaps = require('gulp-sourcemaps');
var prefix = require('gulp-autoprefixer');
var connect = require('gulp-connect');
var browserify = require('gulp-browserify');
var livereload = require('gulp-livereload');
var browsersync = require('browser-sync');
var config = {
srcDir: './assets',
styles: {
src: '/scss/app.scss',
dest: '/stylesheets',
includePaths: [
'node_modules/foundation-sites/scss'
],
prefix: ["last 2 versions", "> 1%", "ie 9"]
},
scripts: {
src: '/js/app.js',
dest: '/js'
},
img: {
src: '/images/**/*',
dest: '/images'
}
};
var srcDir = './src',
destDir = './build';
gulp.task('styles', function() {
return gulp.src(config.srcDir + config.styles.src)
.pipe(sourcemaps.init())
.pipe(sass({
includePaths: config.styles.includePaths,
sourceMap: true,
outFile: config.srcDir + config.styles.dest + '/app.css',
outputStyle: 'compressed'
}))
.pipe(prefix(config.styles.prefix))
.pipe(sourcemaps.write())
.on('error', sass.logError)
.pipe(gulp.dest(config.srcDir + config.styles.dest))
.pipe(browsersync.reload({ stream: true }));
});
gulp.task('scripts', function() {
gulp.src(config.srcDir + config.scripts.src)
.pipe(browserify({
insertGlobals : true,
debug : !gulp.env.production
}))
.pipe(gulp.dest(config.srcDir + config.scripts.dest))
});
gulp.task('include', function() {
return gulp.src(config.srcDir + config.img.src)
.pipe(gulp.dest(config.srcDir + config.img.dest));
});
gulp.task('watch', function () {
// Watch .scss files
gulp.watch(config.srcDir + config.styles.src, ['styles']);
// Watch .js files
gulp.watch(config.srcDir + config.scripts.src, ['scripts']);
});
gulp.task('default', ['styles', 'scripts', 'watch']);
So, not sure how can I do it utilizing gulp. Where can I change the theme without creating the child theme?

Answer 1

Where does the import of "app.css" happen - at the beginning or at the end of the "style.css" file? If it's at the beginning, the changed rules in "app.css" might be overwritten by the following "style.css" rules.