background: □;
□：#33ccff 色碼、Yellow 顏色名稱、RGB、CMYK

background-image: linear-gradient(𝘼, 𝘽);
background-image: linear-gradient(𝘼, 𝘽, 𝘾);
background-image: linear-gradient(𝘼, 𝘽, 𝘾, 𝘿);
background-image: linear-gradient(𝘼, 𝘽, 𝘾, 𝘿, 𝙀, 𝙁, ...);
顏色方向：由上而下
ex：background-image:linear-gradient(red, orange);
ex：background-image:linear-gradient(red, orange, yellow);
ex：background-image:linear-gradient(red, orange, yellow, green);
ex：background-image:linear-gradient(red, orange, yellow, green, blue, purple);
𝘼：red、𝘽：orange、𝘾：yellow、𝘿：green、𝙀：blue、𝙁：purple

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background-image:linear-gradient(to top, 𝘼, 𝘽);
background-image:linear-gradient(to top, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↑
ex：background-image:linear-gradient(to top, #ffffff, #33ccff, #000000);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(to right, 𝘼, 𝘽);
background-image:linear-gradient(to right, 𝘼, 𝘽, 𝘾, ...);
顏色方向：→
ex：background-image:linear-gradient(to right, #ffffff, #33ccff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(to bottom, 𝘼, 𝘽);
background-image:linear-gradient(to bottom, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↓
ex：background-image:linear-gradient(to bottom, #ffffff, #33ccff, #000000);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff
與 background-image: linear-gradient(𝘼, 𝘽, 𝘾, ...); 相同

background-image:linear-gradient(to left, 𝘼, 𝘽);
background-image:linear-gradient(to left, 𝘼, 𝘽, 𝘾, ...);
顏色方向：←
ex：background-image:linear-gradient(to left, #ffffff, #33ccff, #000000);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

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background-image:linear-gradient(to top left, 𝘼, 𝘽);
background-image:linear-gradient(to top left, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↖
ex：background-image: linear-gradient(to top left, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(to top right, 𝘼, 𝘽);
background-image:linear-gradient(to top right, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↗
ex：background-image: linear-gradient(to top right, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(to bottom right, 𝘼, 𝘽);
background-image:linear-gradient(to bottom right, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↘
ex：background-image: linear-gradient(to bottom right, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(to bottom left, 𝘼, 𝘽);
background-image:linear-gradient(to bottom left, 𝘼, 𝘽, 𝘾, ...);
顏色方向：↙
ex：background-image: linear-gradient(to bottom left, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

---

background-image:linear-gradient(0deg, 𝘼, 𝘽);
background-image:linear-gradient(0deg, 𝘼, 𝘽, 𝘾, ...);
顏色方向：
ex：background-image: linear-gradient(0deg, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(90deg, 𝘼, 𝘽);
background-image:linear-gradient(90deg, 𝘼, 𝘽, 𝘾, ...);
顏色方向：
ex：background-image: linear-gradient(90deg, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(180deg, 𝘼, 𝘽);
background-image:linear-gradient(180deg, 𝘼, 𝘽, 𝘾, ...);
顏色方向：
ex：background-image: linear-gradient(180deg, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff

background-image:linear-gradient(135deg, 𝘼, 𝘽);
background-image:linear-gradient(135deg, 𝘼, 𝘽, 𝘾, ...);
顏色方向：
ex：background-image: linear-gradient(, #000000, #33ccff, #ffffff);
𝘼：#000000、𝘽：#33ccff、𝘾：#ffffff