This is how it could look like.
Btw. the numbers down there are the current battlescape palette as a starting point.
customPalettes:
- type: PAL_BATTLESCAPE_COPY
target: PAL_BATTLESCAPE
palette:
0: [0,0,0]
1: [252,252,252]
2: [232,232,232]
3: [216,216,216]
4: [196,196,196]
5: [176,176,176]
6: [160,160,160]
7: [140,140,140]
8: [124,124,124]
9: [104,104,104]
10: [88,88,88]
11: [68,68,68]
12: [52,52,52]
13: [32,32,32]
14: [12,12,12]
15: [0,0,0]
16: [252,208,0]
17: [236,180,0]
18: [224,160,0]
19: [208,136,0]
20: [196,116,0]
21: [180,96,0]
22: [168,80,0]
23: [152,64,0]
24: [140,52,0]
25: [124,36,0]
26: [112,28,0]
27: [96,16,0]
28: [84,8,0]
29: [72,4,0]
30: [56,0,0]
31: [44,0,0]
32: [252,120,120]
33: [236,104,104]
34: [224,92,92]
35: [208,76,76]
36: [196,68,68]
37: [184,56,56]
38: [168,44,44]
39: [156,36,36]
40: [140,28,28]
41: [128,20,20]
42: [116,12,12]
43: [100,8,8]
44: [88,4,4]
45: [72,0,0]
46: [60,0,0]
47: [48,0,0]
48: [160,224,132]
49: [136,208,116]
50: [116,196,100]
51: [92,184,84]
52: [72,172,72]
53: [60,160,64]
54: [48,144,60]
55: [40,132,56]
56: [28,120,56]
57: [20,108,52]
58: [16,96,48]
59: [8,80,44]
60: [4,68,40]
61: [0,56,36]
62: [0,44,28]
63: [0,32,24]
64: [208,228,96]
65: [184,212,84]
66: [164,196,72]
67: [144,184,60]
68: [124,168,48]
69: [104,156,40]
70: [88,140,32]
71: [72,124,24]
72: [56,112,20]
73: [40,96,12]
74: [28,84,8]
75: [16,68,4]
76: [8,52,0]
77: [4,40,0]
78: [0,24,0]
79: [0,12,0]
80: [248,248,248]
81: [232,224,224]
82: [220,208,204]
83: [204,188,184]
84: [192,172,168]
85: [176,156,148]
86: [164,140,132]
87: [148,124,116]
88: [136,108,100]
89: [120,92,88]
90: [108,80,72]
91: [92,68,60]
92: [80,56,48]
93: [68,44,40]
94: [52,32,28]
95: [40,24,20]
96: [240,196,72]
97: [224,176,64]
98: [212,156,52]
99: [200,136,48]
100: [188,120,40]
101: [176,104,32]
102: [160,84,24]
103: [148,72,20]
104: [136,56,16]
105: [124,44,12]
106: [112,32,8]
107: [96,20,4]
108: [84,12,4]
109: [72,4,0]
110: [60,0,0]
111: [48,0,0]
112: [140,176,200]
113: [128,160,188]
114: [112,144,176]
115: [104,128,164]
116: [92,112,152]
117: [80,100,144]
118: [72,84,132]
119: [60,72,120]
120: [52,60,108]
121: [44,48,96]
122: [36,36,88]
123: [32,28,76]
124: [28,24,64]
125: [24,16,52]
126: [20,12,40]
127: [16,8,32]
128: [168,208,240]
129: [148,188,224]
130: [128,172,212]
131: [112,152,200]
132: [96,136,188]
133: [80,120,172]
134: [64,104,160]
135: [52,88,148]
136: [40,72,132]
137: [28,60,120]
138: [20,48,108]
139: [12,36,96]
140: [8,24,80]
141: [4,16,68]
142: [0,8,56]
143: [0,4,44]
144: [252,252,120]
145: [236,228,104]
146: [224,204,92]
147: [208,184,76]
148: [196,160,68]
149: [184,140,56]
150: [168,120,44]
151: [156,100,36]
152: [140,80,28]
153: [128,64,20]
154: [116,48,12]
155: [100,32,8]
156: [88,20,4]
157: [72,8,0]
158: [60,4,0]
159: [48,0,0]
160: [184,160,88]
161: [172,144,76]
162: [160,128,64]
163: [148,112,56]
164: [136,96,44]
165: [124,80,36]
166: [112,68,28]
167: [104,56,24]
168: [92,44,16]
169: [80,32,12]
170: [68,20,8]
171: [56,12,4]
172: [44,8,0]
173: [32,4,0]
174: [20,0,0]
175: [12,0,0]
176: [248,220,212]
177: [232,196,192]
178: [220,176,172]
179: [208,152,152]
180: [192,136,140]
181: [180,120,128]
182: [168,104,120]
183: [152,92,108]
184: [140,76,100]
185: [128,64,92]
186: [112,52,84]
187: [100,44,76]
188: [88,32,68]
189: [72,24,60]
190: [60,16,52]
191: [48,12,44]
192: [216,196,252]
193: [200,172,236]
194: [184,148,224]
195: [172,128,208]
196: [160,108,196]
197: [152,92,180]
198: [140,76,168]
199: [132,60,152]
200: [124,48,140]
201: [116,36,124]
202: [108,24,112]
203: [96,16,96]
204: [84,8,80]
205: [72,4,60]
206: [56,0,44]
207: [44,0,32]
208: [64,196,252]
209: [56,172,236]
210: [48,148,224]
211: [40,128,208]
212: [32,108,196]
213: [28,88,184]
214: [24,72,168]
215: [16,52,156]
216: [12,40,140]
217: [8,24,128]
218: [4,16,116]
219: [4,4,100]
220: [4,0,88]
221: [4,0,72]
222: [8,0,60]
223: [8,0,48]
224: [236,236,248]
225: [216,216,232]
226: [196,196,220]
227: [180,180,208]
228: [164,164,192]
229: [148,144,180]
230: [136,132,168]
231: [120,116,152]
232: [108,100,140]
233: [96,88,128]
234: [84,76,112]
235: [72,64,100]
236: [60,52,88]
237: [52,40,72]
238: [40,32,60]
239: [32,24,48]
240: [140,152,148]
241: [132,136,140]
242: [116,124,132]
243: [108,116,124]
244: [92,104,108]
245: [84,92,100]
246: [76,80,92]
247: [56,68,84]
248: [48,56,68]
249: [40,48,56]
250: [32,36,48]
251: [24,28,32]
252: [16,20,24]
253: [8,12,16]
254: [3,4,8]
255: [3,3,6]