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CSS

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Babel includes JSX processing.

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HTML 

              
                <div id="test" class="class-0 class-1 class-2 class-3 class-4 class-5 class-6 class-7 class-8 class-9 class-10 class-11 class-12 class-13 class-14 class-15 class-16 class-17 class-18 class-19 class-20 class-21 class-22 class-23 class-24 class-25 class-26 class-27 class-28 class-29 class-30 class-31 class-32 class-33 class-34 class-35 class-36 class-37 class-38 class-39 class-40 class-41 class-42 class-43 class-44 class-45 class-46 class-47 class-48 class-49 class-50 class-51 class-52 class-53 class-54 class-55 class-56 class-57 class-58 class-59 class-60 class-61 class-62 class-63 class-64 class-65 class-66 class-67 class-68 class-69 class-70 class-71 class-72 class-73 class-74 class-75 class-76 class-77 class-78 class-79 class-80 class-81 class-82 class-83 class-84 class-85 class-86 class-87 class-88 class-89 class-90 class-91 class-92 class-93 class-94 class-95 class-96 class-97 class-98 class-99 class-100 class-101 class-102 class-103 class-104 class-105 class-106 class-107 class-108 class-109 class-110 class-111 class-112 class-113 class-114 class-115 class-116 class-117 class-118 class-119 class-120 class-121 class-122 class-123 class-124 class-125 class-126 class-127 class-128 class-129 class-130 class-131 class-132 class-133 class-134 class-135 class-136 class-137 class-138 class-139 class-140 class-141 class-142 class-143 class-144 class-145 class-146 class-147 class-148 class-149 class-150 class-151 class-152 class-153 class-154 class-155 class-156 class-157 class-158 class-159 class-160 class-161 class-162 class-163 class-164 class-165 class-166 class-167 class-168 class-169 class-170 class-171 class-172 class-173 class-174 class-175 class-176 class-177 class-178 class-179 class-180 class-181 class-182 class-183 class-184 class-185 class-186 class-187 class-188 class-189 class-190 class-191 class-192 class-193 class-194 class-195 class-196 class-197 class-198 class-199 class-200 class-201 class-202 class-203 class-204 class-205 class-206 class-207 class-208 class-209 class-210 class-211 class-212 class-213 class-214 class-215 class-216 class-217 class-218 class-219 class-220 class-221 class-222 class-223 class-224 class-225 class-226 class-227 class-228 class-229 class-230 class-231 class-232 class-233 class-234 class-235 class-236 class-237 class-238 class-239 class-240 class-241 class-242 class-243 class-244 class-245 class-246 class-247 class-248 class-249 class-250 class-251 class-252 class-253 class-254 class-255 class-256 class-257 class-258 class-259 class-260 class-261 class-262 class-263 class-264 class-265 class-266 class-267 class-268 class-269 class-270 class-271 class-272 class-273 class-274 class-275 class-276 class-277 class-278 class-279 class-280 class-281 class-282 class-283 class-284 class-285 class-286 class-287 class-288 class-289 class-290 class-291 class-292 class-293 class-294 class-295 class-296 class-297 class-298 class-299 class-300 class-301 class-302 class-303 class-304 class-305 class-306 class-307 class-308 class-309 class-310 class-311 class-312 class-313 class-314 class-315 class-316 class-317 class-318 class-319 class-320 class-321 class-322 class-323 class-324 class-325 class-326 class-327 class-328 class-329 class-330 class-331 class-332 class-333 class-334 class-335 class-336 class-337 class-338 class-339 class-340 class-341 class-342 class-343 class-344 class-345 class-346 class-347 class-348 class-349 class-350 class-351 class-352 class-353 class-354 class-355 class-356 class-357 class-358 class-359 class-360 class-361 class-362 class-363 class-364 class-365 class-366 class-367 class-368 class-369 class-370 class-371 class-372 class-373 class-374 class-375 class-376 class-377 class-378 class-379 class-380 class-381 class-382 class-383 class-384 class-385 class-386 class-387 class-388 class-389 class-390 class-391 class-392 class-393 class-394 class-395 class-396 class-397 class-398 class-399 class-400 class-401 class-402 class-403 class-404 class-405 class-406 class-407 class-408 class-409 class-410 class-411 class-412 class-413 class-414 class-415 class-416 class-417 class-418 class-419 class-420 class-421 class-422 class-423 class-424 class-425 class-426 class-427 class-428 class-429 class-430 class-431 class-432 class-433 class-434 class-435 class-436 class-437 class-438 class-439 class-440 class-441 class-442 class-443 class-444 class-445 class-446 class-447 class-448 class-449 class-450 class-451 class-452 class-453 class-454 class-455 class-456 class-457 class-458 class-459 class-460 class-461 class-462 class-463 class-464 class-465 class-466 class-467 class-468 class-469 class-470 class-471 class-472 class-473 class-474 class-475 class-476 class-477 class-478 class-479 class-480 class-481 class-482 class-483 class-484 class-485 class-486 class-487 class-488 class-489 class-490 class-491 class-492 class-493 class-494 class-495 class-496 class-497 class-498 class-499 class-500">You can't override an ID with classes only!</div>
!

CSS 

              
                @import "compass/css3";

#test {
  background: red;
}
div {
  width: 200px;
  height: 3em;
  padding: 1em;
  color: #fff;
  font-weight: bold;
  position: relative;
  text-align: center;
}
.class-0.class-1.class-2.class-3.class-4.class-5.class-6.class-7.class-8.class-9.class-10.class-11.class-12.class-13.class-14.class-15.class-16.class-17.class-18.class-19.class-20.class-21.class-22.class-23.class-24.class-25.class-26.class-27.class-28.class-29.class-30.class-31.class-32.class-33.class-34.class-35.class-36.class-37.class-38.class-39.class-40.class-41.class-42.class-43.class-44.class-45.class-46.class-47.class-48.class-49.class-50.class-51.class-52.class-53.class-54.class-55.class-56.class-57.class-58.class-59.class-60.class-61.class-62.class-63.class-64.class-65.class-66.class-67.class-68.class-69.class-70.class-71.class-72.class-73.class-74.class-75.class-76.class-77.class-78.class-79.class-80.class-81.class-82.class-83.class-84.class-85.class-86.class-87.class-88.class-89.class-90.class-91.class-92.class-93.class-94.class-95.class-96.class-97.class-98.class-99.class-100.class-101.class-102.class-103.class-104.class-105.class-106.class-107.class-108.class-109.class-110.class-111.class-112.class-113.class-114.class-115.class-116.class-117.class-118.class-119.class-120.class-121.class-122.class-123.class-124.class-125.class-126.class-127.class-128.class-129.class-130.class-131.class-132.class-133.class-134.class-135.class-136.class-137.class-138.class-139.class-140.class-141.class-142.class-143.class-144.class-145.class-146.class-147.class-148.class-149.class-150.class-151.class-152.class-153.class-154.class-155.class-156.class-157.class-158.class-159.class-160.class-161.class-162.class-163.class-164.class-165.class-166.class-167.class-168.class-169.class-170.class-171.class-172.class-173.class-174.class-175.class-176.class-177.class-178.class-179.class-180.class-181.class-182.class-183.class-184.class-185.class-186.class-187.class-188.class-189.class-190.class-191.class-192.class-193.class-194.class-195.class-196.class-197.class-198.class-199.class-200.class-201.class-202.class-203.class-204.class-205.class-206.class-207.class-208.class-209.class-210.class-211.class-212.class-213.class-214.class-215.class-216.class-217.class-218.class-219.class-220.class-221.class-222.class-223.class-224.class-225.class-226.class-227.class-228.class-229.class-230.class-231.class-232.class-233.class-234.class-235.class-236.class-237.class-238.class-239.class-240.class-241.class-242.class-243.class-244.class-245.class-246.class-247.class-248.class-249.class-250.class-251.class-252.class-253.class-254.class-255.class-256.class-257.class-258.class-259.class-260.class-261.class-262.class-263.class-264.class-265.class-266.class-267.class-268.class-269.class-270.class-271.class-272.class-273.class-274.class-275.class-276.class-277.class-278.class-279.class-280.class-281.class-282.class-283.class-284.class-285.class-286.class-287.class-288.class-289.class-290.class-291.class-292.class-293.class-294.class-295.class-296.class-297.class-298.class-299.class-300.class-301.class-302.class-303.class-304.class-305.class-306.class-307.class-308.class-309.class-310.class-311.class-312.class-313.class-314.class-315.class-316.class-317.class-318.class-319.class-320.class-321.class-322.class-323.class-324.class-325.class-326.class-327.class-328.class-329.class-330.class-331.class-332.class-333.class-334.class-335.class-336.class-337.class-338.class-339.class-340.class-341.class-342.class-343.class-344.class-345.class-346.class-347.class-348.class-349.class-350.class-351.class-352.class-353.class-354.class-355.class-356.class-357.class-358.class-359.class-360.class-361.class-362.class-363.class-364.class-365.class-366.class-367.class-368.class-369.class-370.class-371.class-372.class-373.class-374.class-375.class-376.class-377.class-378.class-379.class-380.class-381.class-382.class-383.class-384.class-385.class-386.class-387.class-388.class-389.class-390.class-391.class-392.class-393.class-394.class-395.class-396.class-397.class-398.class-399.class-400.class-401.class-402.class-403.class-404.class-405.class-406.class-407.class-408.class-409.class-410.class-411.class-412.class-413.class-414.class-415.class-416.class-417.class-418.class-419.class-420.class-421.class-422.class-423.class-424.class-425.class-426.class-427.class-428.class-429.class-430.class-431.class-432.class-433.class-434.class-435.class-436.class-437.class-438.class-439.class-440.class-441.class-442.class-443.class-444.class-445.class-446.class-447.class-448.class-449.class-450.class-451.class-452.class-453.class-454.class-455.class-456.class-457.class-458.class-459.class-460.class-461.class-462.class-463.class-464.class-465.class-466.class-467.class-468.class-469.class-470.class-471.class-472.class-473.class-474.class-475.class-476.class-477.class-478.class-479.class-480.class-481.class-482.class-483.class-484.class-485.class-486.class-487.class-488.class-489.class-490.class-491.class-492.class-493.class-494.class-495.class-496.class-497.class-498.class-499.class-500 {
  background: blue;
}
!

JS 

              
                var max_classes = 500, classes = [], class_name = 'class-';

for(var i = 0; i <= max_classes; i++){
  classes.push(class_name+i);
}

$('body').append('<style>.'+classes.join('.')+' {background: blue;}</style><p>.'+classes.join(' .')+' div {<br>&nbsp;&nbsp;background: blue;<br>}</p>');

$('#test').addClass(classes.join(' '));
!
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