/* Biểu tượng dùng chung (app người dân + web quản lý): icon nét + ô biểu tượng 3D. */
.bt-svg { display: inline-flex; width: 1.2em; height: 1.2em; flex: none; vertical-align: -.22em; }
.bt-svg svg { width: 100%; height: 100%; }

/* Ô 3D: nền chuyển sắc sáng → đậm, viền sáng phía trên, đáy tối, bóng đổ cùng màu, lớp bóng kính nửa trên. */
.o-bt { --c1: #6aa8ff; --c2: #1a5fd0; --bong-mau: rgba(26, 95, 208, .42);
  position: relative; isolation: isolate; display: inline-grid; place-items: center; flex: none; width: 50px; height: 50px; border-radius: 16px;
  color: #fff; background: linear-gradient(155deg, var(--c1) 0%, var(--c2) 100%);
  box-shadow: 0 7px 14px -5px var(--bong-mau), 0 2px 4px -1px var(--bong-mau),
    inset 0 1.5px 0 rgba(255, 255, 255, .55), inset 0 -3px 5px rgba(0, 0, 0, .16);
  transition: transform .12s ease, box-shadow .12s ease; }
.o-bt::before { content: ""; position: absolute; z-index: -1; left: 3px; right: 3px; top: 2px; height: 48%;
  border-radius: 13px 13px 50% 50% / 13px 13px 10px 10px; background: linear-gradient(180deg, rgba(255, 255, 255, .42), rgba(255, 255, 255, 0)); pointer-events: none; }
.o-bt::after { content: ""; position: absolute; z-index: -1; right: 6px; bottom: 5px; width: 40%; height: 40%; border-radius: 50%;
  background: radial-gradient(circle, rgba(255, 255, 255, .18), rgba(255, 255, 255, 0) 70%); pointer-events: none; }
.o-bt .bt-svg { width: 52%; height: 52%; filter: drop-shadow(0 1.5px 1.2px rgba(0, 0, 0, .28)); }
.o-bt .bt-svg svg { stroke-width: 2.1; }
.o-bt.nho { width: 26px; height: 26px; border-radius: 8px; box-shadow: 0 3px 6px -3px var(--bong-mau), inset 0 1px 0 rgba(255, 255, 255, .5), inset 0 -2px 3px rgba(0, 0, 0, .15); }
.o-bt.nho::before { border-radius: 7px 7px 50% 50% / 7px 7px 5px 5px; left: 2px; right: 2px; top: 1px; }
.o-bt.nho::after { display: none; }
.o-bt.nho .bt-svg { width: 60%; height: 60%; }

.o-bt.m-xanh { --c1: #6aa8ff; --c2: #1a5fd0; --bong-mau: rgba(26, 95, 208, .42); }
.o-bt.m-luc { --c1: #5fdb98; --c2: #128245; --bong-mau: rgba(18, 130, 69, .38); }
.o-bt.m-cam { --c1: #ffbe6b; --c2: #ea620b; --bong-mau: rgba(234, 98, 11, .4); }
.o-bt.m-hong { --c1: #ff8db0; --c2: #d12a5f; --bong-mau: rgba(209, 42, 95, .38); }
.o-bt.m-tim { --c1: #b39bff; --c2: #5a35cb; --bong-mau: rgba(90, 53, 203, .4); }
.o-bt.m-ngoc { --c1: #5fe0e4; --c2: #0a8590; --bong-mau: rgba(10, 133, 144, .38); }
.o-bt.m-vang { --c1: #ffd86a; --c2: #dc9500; --bong-mau: rgba(220, 149, 0, .4); }
.o-bt.m-xam { --c1: #a9b5c8; --c2: #4b586e; --bong-mau: rgba(75, 88, 110, .38); }
.o-bt.m-cham { --c1: #7f9bff; --c2: #2b43b5; --bong-mau: rgba(43, 67, 181, .4); }
.o-bt.m-do { --c1: #ff8a80; --c2: #d32f2f; --bong-mau: rgba(211, 47, 47, .38); }