CSS/グラデーション
①(to bottom, blue, #eee)
②(to top, #111, #888, #aaa, #eee)
③(to right, green, #eee)
④(to left, #111, #666, #aaa, #eee)
⑤(to bottom right, red, #eee)
⑥(to top left, purple, #eee)
⑦(-120deg, navy, #eee)
⑧(45deg, red, orange, yellow, green, blue, indigo, violet)
⑨(to left, #eee, #00ffff, #eee)
⑩(to left, #111, #ddd, #333)
⑪radial-gradient(#222, #eee)
⑫radial-gradient(#eee, #aaa, #555, #222)
⑬radial-gradient(darkgreen 1%, green 5% , #eee)
⑭repeating-linear-gradient(-45deg, #ccc, #ccc 5px, white 5px, white 10px)
⑮repeating-radial-gradient(#ccc, #ccc 5px, #eee 15px, #eee 10px)