/* Ý 8 – Bộ sưu tập ảnh nền. Mỗi chủ đề là lớp "t-…" dùng chung cho lớp nền toàn trang (.fa-bg)
   và ô xem trước nhỏ (.fa-bg-mini). Hình vẽ là SVG nằm ngay trong file, không tải ảnh từ mạng.
   Hiệu ứng chỉ dùng transform và opacity; tắt hết khi máy bật "giảm chuyển động". */

/* ---------- Lớp nền toàn trang (nằm sau mọi nội dung) ---------- */
.fa-bg { position: fixed; inset: 0; z-index: -2; overflow: hidden; pointer-events: none; }
.fa-bg.t-nang-am { display: none; }                  /* mặc định: giữ nền kem + ánh nắng sẵn có của app */
body:has(.fa-bg:not(.t-nang-am))::before { opacity: 0; } /* chủ đề khác thì tắt ánh nắng góc trang */
.fa-art { background-color: var(--fa-bg); }
.fa-art::before, .fa-art::after { content: ''; position: absolute; pointer-events: none; }
.fa-bg-img { display: none; position: absolute; inset: 0; width: 100%; height: 100%; object-fit: cover; }
.fa-bg .fa-bg-img { filter: blur(3px); transform: scale(1.04); } /* làm mờ nhẹ để ảnh không tranh với nội dung */
.fa-bg-deco { position: absolute; top: -8%; width: 26px; height: 26px; opacity: 0; background: no-repeat center / contain; }

/* Rơi chầm chậm (cánh hoa, lá) và bay ngang (chim) */
@keyframes fa-bg-fall {
  0%   { transform: translate3d(0, 0, 0) rotate(0deg); opacity: 0; }
  10%  { opacity: .9; }
  50%  { transform: translate3d(40px, 55vh, 0) rotate(160deg); }
  90%  { opacity: .85; }
  100% { transform: translate3d(-20px, 115vh, 0) rotate(320deg); opacity: 0; }
}
@keyframes fa-bg-fly {
  0%   { transform: translate3d(-10vw, 0, 0) scale(.9); opacity: 0; }
  10%  { opacity: .8; }
  50%  { transform: translate3d(50vw, -4vh, 0) scale(1); }
  90%  { opacity: .8; }
  100% { transform: translate3d(115vw, 2vh, 0) scale(.9); opacity: 0; }
}
@keyframes fa-bg-wave { to { transform: translate3d(-400px, 0, 0); } }
@keyframes fa-bg-sway { 0%, 100% { transform: rotate(-2deg); } 50% { transform: rotate(2deg); } }
@keyframes fa-bg-sway-flip { 0%, 100% { transform: rotate(178deg); } 50% { transform: rotate(182deg); } }

.fa-bg .fa-bg-deco { animation: fa-bg-fall 18s linear infinite; }
.fa-bg .fa-bg-deco:nth-child(2) { left: 8%;  animation-delay: -2s;  animation-duration: 21s; }
.fa-bg .fa-bg-deco:nth-child(3) { left: 24%; animation-delay: -9s;  animation-duration: 17s; width: 20px; height: 20px; }
.fa-bg .fa-bg-deco:nth-child(4) { left: 41%; animation-delay: -14s; animation-duration: 23s; }
.fa-bg .fa-bg-deco:nth-child(5) { left: 58%; animation-delay: -5s;  animation-duration: 19s; width: 22px; height: 22px; }
.fa-bg .fa-bg-deco:nth-child(6) { left: 74%; animation-delay: -11s; animation-duration: 25s; }
.fa-bg .fa-bg-deco:nth-child(7) { left: 90%; animation-delay: -16s; animation-duration: 20s; width: 18px; height: 18px; }

/* ---------- Ô xem trước nhỏ ở trang Ảnh nền ---------- */
.fa-bg-mini { position: relative; display: block; overflow: hidden; aspect-ratio: 16 / 10; border-radius: 14px; }
.fa-bg-mini.t-nang-am { background: radial-gradient(circle at 88% 0%, rgba(255, 206, 110, .7), rgba(255, 214, 150, .25) 35%, rgba(255, 248, 236, 0) 62%), var(--fa-bg); }
.fa-bg-mini .fa-bg-deco { opacity: .9; width: 14px; height: 14px; }
.fa-bg-mini .fa-bg-deco:nth-child(1) { left: 86%; top: 14%; }
.fa-bg-mini .fa-bg-deco:nth-child(2) { left: 12%; top: 18%; transform: rotate(20deg); }
.fa-bg-mini .fa-bg-deco:nth-child(3) { left: 34%; top: 46%; transform: rotate(-30deg); }
.fa-bg-mini .fa-bg-deco:nth-child(4) { left: 58%; top: 22%; transform: rotate(70deg); }
.fa-bg-mini .fa-bg-deco:nth-child(5) { left: 78%; top: 52%; transform: rotate(10deg); }
.fa-bg-mini .fa-bg-deco:nth-child(6), .fa-bg-mini .fa-bg-deco:nth-child(7) { display: none; }
.fa-bg-mini .fa-bg-img { display: block; }

/* ---------- Biển xanh ---------- */
.fa-art.t-bien { background: radial-gradient(circle at 82% 12%, rgba(255, 236, 170, .8), rgba(255, 236, 170, 0) 22%),
  linear-gradient(180deg, #E1F3F8 0%, #EEF8F7 48%, #FFF8EC 100%); }
.fa-art.t-bien::before { left: 0; right: -400px; bottom: 0; height: 90px; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 400 60' width='400' height='60'%3E%3Cpath d='M0 34 Q50 52 100 34 T200 34 T300 34 T400 34 V60 H0Z' fill='%23A9DBE8'/%3E%3C/svg%3E") repeat-x left bottom / 400px 60px, url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 400 60' width='400' height='60'%3E%3Cpath d='M0 30 Q50 8 100 30 T200 30 T300 30 T400 30 V60 H0Z' fill='%23C6E8F1'/%3E%3C/svg%3E") repeat-x left 4px bottom 18px / 400px 60px; }
.fa-bg.t-bien::before { animation: fa-bg-wave 24s linear infinite; }
.fa-art.t-bien .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 40 20'%3E%3Cpath d='M2 13 Q10 2 20 12 Q30 2 38 13' fill='none' stroke='%236FA9BC' stroke-width='2.6' stroke-linecap='round'/%3E%3C/svg%3E"); width: 34px; height: 17px; }
.fa-bg.t-bien .fa-bg-deco { top: auto; animation-name: fa-bg-fly; animation-duration: 38s; }
.fa-bg.t-bien .fa-bg-deco:nth-child(n) { left: 0; }
.fa-bg.t-bien .fa-bg-deco:nth-child(2) { top: 14%; } .fa-bg.t-bien .fa-bg-deco:nth-child(3) { top: 20%; }
.fa-bg.t-bien .fa-bg-deco:nth-child(4) { top: 9%; }  .fa-bg.t-bien .fa-bg-deco:nth-child(n+5) { display: none; }

/* ---------- Vườn hoa ---------- */
.fa-art.t-hoa { background: linear-gradient(170deg, #FFEFF3 0%, #FFF5F0 45%, #FFF8EC 100%); }
.fa-art.t-hoa::before { inset: 0; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 130 130' width='130' height='130'%3E%3Cg fill='%23F9CBD5'%3E%3Ccircle cx='30' cy='22' r='7'/%3E%3Ccircle cx='38' cy='30' r='7'/%3E%3Ccircle cx='30' cy='38' r='7'/%3E%3Ccircle cx='22' cy='30' r='7'/%3E%3C/g%3E%3Ccircle cx='30' cy='30' r='3.9' fill='%23F5C15A'/%3E%3Cg fill='%23FFD9C2'%3E%3Ccircle cx='95' cy='85' r='6'/%3E%3Ccircle cx='102' cy='92' r='6'/%3E%3Ccircle cx='95' cy='99' r='6'/%3E%3Ccircle cx='88' cy='92' r='6'/%3E%3C/g%3E%3Ccircle cx='95' cy='92' r='3.3' fill='%23F5C15A'/%3E%3Ccircle cx='92' cy='26' r='3' fill='%23F9CBD5'/%3E%3Ccircle cx='26' cy='96' r='2.5' fill='%23FFD9C2'/%3E%3C/svg%3E") repeat 0 0 / 130px 130px; opacity: .55; }
.fa-bg-mini.t-hoa::before { background-size: 60px 60px; }
.fa-art.t-hoa .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cpath d='M15 2 C25 9 24 21 15 28 C6 21 5 9 15 2Z' fill='%23F6B3C1'/%3E%3Cpath d='M15 6 C18 12 18 18 15 24' stroke='%23FBD3DB' stroke-width='1.4' fill='none'/%3E%3C/svg%3E"); }

/* ---------- Tết sum vầy ---------- */
.fa-art.t-tet { background: radial-gradient(circle at 50% 120%, rgba(255, 200, 120, .45), rgba(255, 200, 120, 0) 55%),
  linear-gradient(160deg, #FFEDE0 0%, #FFF8EC 52%, #FFEFE3 100%); }
.fa-art.t-tet::before { bottom: 0; right: 0; width: min(40vw, 380px); aspect-ratio: 320 / 200; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 320 200' width='320' height='200'%3E%3Cpath d='M-5 20 C70 30 130 60 190 120 C220 150 250 165 300 170' stroke='%237A5640' stroke-width='6' fill='none' stroke-linecap='round'/%3E%3Cpath d='M95 45 C125 25 150 18 185 18' stroke='%237A5640' stroke-width='3.5' fill='none' stroke-linecap='round'/%3E%3Cpath d='M160 100 C170 70 185 60 205 55' stroke='%237A5640' stroke-width='3' fill='none' stroke-linecap='round'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='60.0' cy='22.5' r='6.2'/%3E%3Ccircle cx='67.1' cy='27.7' r='6.2'/%3E%3Ccircle cx='64.4' cy='36.1' r='6.2'/%3E%3Ccircle cx='55.6' cy='36.1' r='6.2'/%3E%3Ccircle cx='52.9' cy='27.7' r='6.2'/%3E%3C/g%3E%3Ccircle cx='60' cy='30' r='3.2' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='120.0' cy='29.4' r='5.5'/%3E%3Ccircle cx='126.3' cy='34.0' r='5.5'/%3E%3Ccircle cx='123.9' cy='41.3' r='5.5'/%3E%3Ccircle cx='116.1' cy='41.3' r='5.5'/%3E%3Ccircle cx='113.7' cy='34.0' r='5.5'/%3E%3C/g%3E%3Ccircle cx='120' cy='36' r='2.9' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='150.0' cy='14.0' r='5.0'/%3E%3Ccircle cx='155.7' cy='18.1' r='5.0'/%3E%3Ccircle cx='153.5' cy='24.9' r='5.0'/%3E%3Ccircle cx='146.5' cy='24.9' r='5.0'/%3E%3Ccircle cx='144.3' cy='18.1' r='5.0'/%3E%3C/g%3E%3Ccircle cx='150' cy='20' r='2.6' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='185.0' cy='10.8' r='6.0'/%3E%3Ccircle cx='191.8' cy='15.8' r='6.0'/%3E%3Ccircle cx='189.2' cy='23.8' r='6.0'/%3E%3Ccircle cx='180.8' cy='23.8' r='6.0'/%3E%3Ccircle cx='178.2' cy='15.8' r='6.0'/%3E%3C/g%3E%3Ccircle cx='185' cy='18' r='3.1' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='205.0' cy='48.4' r='5.5'/%3E%3Ccircle cx='211.3' cy='53.0' r='5.5'/%3E%3Ccircle cx='208.9' cy='60.3' r='5.5'/%3E%3Ccircle cx='201.1' cy='60.3' r='5.5'/%3E%3Ccircle cx='198.7' cy='53.0' r='5.5'/%3E%3C/g%3E%3Ccircle cx='205' cy='55' r='2.9' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='178.0' cy='64.6' r='4.5'/%3E%3Ccircle cx='183.1' cy='68.3' r='4.5'/%3E%3Ccircle cx='181.2' cy='74.4' r='4.5'/%3E%3Ccircle cx='174.8' cy='74.4' r='4.5'/%3E%3Ccircle cx='172.9' cy='68.3' r='4.5'/%3E%3C/g%3E%3Ccircle cx='178' cy='70' r='2.3' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='230.0' cy='142.2' r='6.5'/%3E%3Ccircle cx='237.4' cy='147.6' r='6.5'/%3E%3Ccircle cx='234.6' cy='156.3' r='6.5'/%3E%3Ccircle cx='225.4' cy='156.3' r='6.5'/%3E%3Ccircle cx='222.6' cy='147.6' r='6.5'/%3E%3C/g%3E%3Ccircle cx='230' cy='150' r='3.4' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='270.0' cy='160.0' r='5.0'/%3E%3Ccircle cx='275.7' cy='164.1' r='5.0'/%3E%3Ccircle cx='273.5' cy='170.9' r='5.0'/%3E%3Ccircle cx='266.5' cy='170.9' r='5.0'/%3E%3Ccircle cx='264.3' cy='164.1' r='5.0'/%3E%3C/g%3E%3Ccircle cx='270' cy='166' r='2.6' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='300.0' cy='163.1' r='5.8'/%3E%3Ccircle cx='306.6' cy='167.9' r='5.8'/%3E%3Ccircle cx='304.1' cy='175.6' r='5.8'/%3E%3Ccircle cx='295.9' cy='175.6' r='5.8'/%3E%3Ccircle cx='293.4' cy='167.9' r='5.8'/%3E%3C/g%3E%3Ccircle cx='300' cy='170' r='3.0' fill='%23E8833A'/%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='30.0' cy='14.6' r='4.5'/%3E%3Ccircle cx='35.1' cy='18.3' r='4.5'/%3E%3Ccircle cx='33.2' cy='24.4' r='4.5'/%3E%3Ccircle cx='26.8' cy='24.4' r='4.5'/%3E%3Ccircle cx='24.9' cy='18.3' r='4.5'/%3E%3C/g%3E%3Ccircle cx='30' cy='20' r='2.3' fill='%23E8833A'/%3E%3Ccircle cx='88' cy='42' r='3' fill='%239BC27A'/%3E%3Ccircle cx='140' cy='80' r='3' fill='%239BC27A'/%3E%3Ccircle cx='250' cy='160' r='3' fill='%239BC27A'/%3E%3C/svg%3E") no-repeat left top / contain;
  opacity: .8; transform: rotate(180deg); transform-origin: center; }
.fa-art.t-tet::after { top: 76px; right: 2.5%; width: 40px; height: 60px; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 40 60' width='40' height='60'%3E%3Cpath d='M20 0 V8' stroke='%23B85E1E' stroke-width='2'/%3E%3Crect x='12' y='8' width='16' height='4' rx='1.5' fill='%23E0A23B'/%3E%3Cellipse cx='20' cy='26' rx='15' ry='14' fill='%23E24B3B'/%3E%3Cpath d='M20 12 V40 M12 14 C8 22 8 30 12 38 M28 14 C32 22 32 30 28 38' stroke='%23C23A2C' stroke-width='1.4' fill='none'/%3E%3Crect x='12' y='38' width='16' height='4' rx='1.5' fill='%23E0A23B'/%3E%3Cpath d='M17 42 V56 M20 42 V58 M23 42 V56' stroke='%23E0A23B' stroke-width='1.6'/%3E%3C/svg%3E") no-repeat center top / contain; transform-origin: center top; }
.fa-bg.t-tet::before { animation: fa-bg-sway-flip 9s ease-in-out infinite; }
.fa-bg.t-tet::after { animation: fa-bg-sway 5s ease-in-out infinite; }
.fa-bg-mini.t-tet::before { width: 62%; }
.fa-bg-mini.t-tet::after { top: 6px; width: 16px; height: 24px; }
.fa-bg-mini.t-bien::before { height: 34px; background-size: 160px 24px, 160px 24px; background-position: left bottom, left 2px bottom 8px; }
.fa-art.t-tet .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cg fill='%23F7C531'%3E%3Ccircle cx='15.0' cy='9.0' r='5.0'/%3E%3Ccircle cx='20.7' cy='13.1' r='5.0'/%3E%3Ccircle cx='18.5' cy='19.9' r='5.0'/%3E%3Ccircle cx='11.5' cy='19.9' r='5.0'/%3E%3Ccircle cx='9.3' cy='13.1' r='5.0'/%3E%3C/g%3E%3Ccircle cx='15' cy='15' r='2.6' fill='%23E8833A'/%3E%3C/svg%3E"); width: 20px; height: 20px; }

/* ---------- Rừng xanh ---------- */
.fa-art.t-rung { background: linear-gradient(180deg, #EAF5E3 0%, #F4F9EC 50%, #FFF8EC 100%); }
.fa-art.t-rung::before { inset: 0; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 140 130' width='140' height='130'%3E%3Cg opacity='.9'%3E%3Cpath d='M14 40 C14 22 26 14 42 14 C42 30 32 40 14 40Z' fill='%23CFE6C3'/%3E%3Cpath d='M90 100 C90 86 100 80 112 80 C112 92 104 100 90 100Z' fill='%23DCEDD2'/%3E%3Cpath d='M100 30 C110 22 118 22 126 26 C120 34 110 36 100 30Z' fill='%23D5EAC9'/%3E%3C/g%3E%3C/svg%3E") repeat 0 0 / 140px 130px; opacity: .7; }
.fa-bg-mini.t-rung::before { background-size: 64px 60px; }
.fa-art.t-rung::after { left: 0; right: 0; bottom: 0; height: 18vh; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 600 120' width='600' height='120'%3E%3Cpath d='M0 70 C120 20 220 30 340 60 C440 85 520 40 600 50 V120 H0Z' fill='%23CFE6BF'/%3E%3Cpath d='M0 95 C140 60 260 70 380 90 C480 105 540 80 600 85 V120 H0Z' fill='%23B6D9A3'/%3E%3C/svg%3E") no-repeat center bottom / 100% 100%; opacity: .8; }
.fa-bg-mini.t-rung::after { height: 28%; }
.fa-art.t-rung .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cpath d='M4 26 C4 10 14 4 26 4 C26 18 18 26 4 26Z' fill='%239CCB86'/%3E%3Cpath d='M5 25 L21 9' stroke='%236FA35A' stroke-width='1.5'/%3E%3C/svg%3E"); }

/* ---------- Hoàng hôn ---------- */
.fa-art.t-hoang-hon { background: radial-gradient(circle at 50% 100%, rgba(255, 190, 110, .75), rgba(255, 190, 110, 0) 38%),
  linear-gradient(180deg, #F7E1EE 0%, #FFE5D6 48%, #FFF3E4 100%); }
.fa-art.t-hoang-hon::after { left: 0; right: 0; bottom: 0; height: 16vh; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 600 120' width='600' height='120'%3E%3Cpath d='M0 80 C100 40 200 50 300 70 C400 90 500 45 600 60 V120 H0Z' fill='%23E8C3D6'/%3E%3Cpath d='M0 100 C150 70 260 85 380 95 C470 103 540 88 600 92 V120 H0Z' fill='%23D9A9C3'/%3E%3C/svg%3E") no-repeat center bottom / 100% 100%; opacity: .75; }
.fa-bg-mini.t-hoang-hon::after { height: 26%; }
.fa-art.t-hoang-hon .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 32 16'%3E%3Cpath d='M2 12 Q9 4 16 11 Q23 4 30 12' fill='none' stroke='%238A5C7A' stroke-width='2.2' stroke-linecap='round'/%3E%3C/svg%3E"); width: 30px; height: 15px; }
.fa-bg.t-hoang-hon .fa-bg-deco { animation-name: fa-bg-fly; animation-duration: 42s; }
.fa-bg.t-hoang-hon .fa-bg-deco:nth-child(n) { left: 0; }
.fa-bg.t-hoang-hon .fa-bg-deco:nth-child(2) { top: 18%; } .fa-bg.t-hoang-hon .fa-bg-deco:nth-child(3) { top: 22%; }
.fa-bg.t-hoang-hon .fa-bg-deco:nth-child(4) { top: 15%; } .fa-bg.t-hoang-hon .fa-bg-deco:nth-child(n+5) { display: none; }

/* ---------- Mùa thu ---------- */
.fa-art.t-thu { background: linear-gradient(175deg, #FFEBD6 0%, #FFF4E6 50%, #FFF8EC 100%); }
.fa-art.t-thu::before { inset: 0; background: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 140 130' width='140' height='130'%3E%3Cg opacity='.55'%3E%3Cpath transform='translate(10 14) scale(.9) rotate(-15 15 15)' d='M15 1 L18 9 L25 6 L22 13 L29 15 L22 18 L24 25 L17 21.5 L15.8 29 L14.2 29 L13 21.5 L6 25 L8 18 L1 15 L8 13 L5 6 L12 9Z' fill='%23F8D3AE'/%3E%3Cpath transform='translate(90 80) scale(.7) rotate(25 15 15)' d='M15 1 L18 9 L25 6 L22 13 L29 15 L22 18 L24 25 L17 21.5 L15.8 29 L14.2 29 L13 21.5 L6 25 L8 18 L1 15 L8 13 L5 6 L12 9Z' fill='%23F6C7A4'/%3E%3C/g%3E%3C/svg%3E") repeat 0 0 / 140px 130px; }
.fa-bg-mini.t-thu::before { background-size: 64px 60px; }
.fa-art.t-thu .fa-bg-deco { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cpath d='M15 1 L18 9 L25 6 L22 13 L29 15 L22 18 L24 25 L17 21.5 L15.8 29 L14.2 29 L13 21.5 L6 25 L8 18 L1 15 L8 13 L5 6 L12 9Z' fill='%23E8833A'/%3E%3C/svg%3E"); }
.fa-art.t-thu .fa-bg-deco:nth-child(3n) { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cpath d='M15 1 L18 9 L25 6 L22 13 L29 15 L22 18 L24 25 L17 21.5 L15.8 29 L14.2 29 L13 21.5 L6 25 L8 18 L1 15 L8 13 L5 6 L12 9Z' fill='%23D9573A'/%3E%3C/svg%3E"); }
.fa-art.t-thu .fa-bg-deco:nth-child(3n+1) { background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3E%3Cpath d='M15 1 L18 9 L25 6 L22 13 L29 15 L22 18 L24 25 L17 21.5 L15.8 29 L14.2 29 L13 21.5 L6 25 L8 18 L1 15 L8 13 L5 6 L12 9Z' fill='%23F5B041'/%3E%3C/svg%3E"); }

/* ---------- Ảnh của tôi ---------- */
.fa-art.t-anh-rieng .fa-bg-img { display: block; }
.fa-art.t-anh-rieng::after { inset: 0; background: linear-gradient(180deg, rgba(255, 248, 236, .66), rgba(255, 248, 236, .78)); }
.fa-bg-mini.t-anh-rieng::after { background: rgba(255, 248, 236, .25); }
.fa-art.t-anh-rieng .fa-bg-deco { display: none; }
.fa-bg-mini.t-anh-rieng.no-image { display: grid; place-items: center; background: repeating-linear-gradient(135deg, var(--fa-soft) 0 12px, var(--fa-bg) 12px 24px); color: var(--fa-amber-dark); font-size: 1.8rem; }

/* ---------- Trang "Ảnh nền" ---------- */
.fa-bg-grid { display: grid; gap: 1rem; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr)); }
.fa-bgcard { position: relative; display: block; cursor: pointer; background: var(--fa-surface); border: 2px solid var(--fa-line); border-radius: 18px; padding: .5rem;
  box-shadow: var(--fa-shadow); transition: transform .35s var(--fa-ease), box-shadow .35s var(--fa-ease); }
.fa-bgcard:hover { transform: translateY(-4px); box-shadow: var(--fa-shadow-lg); }
.fa-bgcard input { position: absolute; opacity: 0; pointer-events: none; }
.fa-bgcard:has(input:checked) { border-color: var(--fa-amber); }
.fa-bgcard:has(input:focus-visible) { outline: 3px solid var(--fa-honey); outline-offset: 2px; }
.fa-bgcard-body { display: flex; gap: .55rem; align-items: flex-start; padding: .6rem .35rem .25rem; }
.fa-bgcard-body i { color: var(--fa-amber); font-size: 1.15rem; }
.fa-bgcard-body strong { display: block; line-height: 1.2; }
.fa-bgcard-body small { color: var(--fa-muted); line-height: 1.3; display: block; }
.fa-bgcard-check { position: absolute; top: .9rem; right: .9rem; width: 30px; height: 30px; border-radius: 50%; display: grid; place-items: center;
  background: linear-gradient(135deg, var(--fa-honey), var(--fa-amber)); color: #fff; opacity: 0; transform: scale(.4);
  transition: opacity .3s var(--fa-ease), transform .3s var(--fa-ease); }
.fa-bgcard:has(input:checked) .fa-bgcard-check { opacity: 1; transform: scale(1); }
.fa-bg-savebar { position: sticky; bottom: 1rem; z-index: 5; display: flex; flex-wrap: wrap; gap: .75rem; align-items: center; justify-content: space-between;
  background: rgba(255, 253, 248, .94); backdrop-filter: blur(8px); -webkit-backdrop-filter: blur(8px);
  border: 1px solid var(--fa-line); border-radius: 999px; padding: .5rem .6rem .5rem 1.2rem; box-shadow: var(--fa-shadow-lg); }
.fa-bg-upload-preview { width: 100%; max-height: 220px; object-fit: cover; border-radius: 14px; display: none; }
.fa-bg-upload-preview.show { display: block; }

.fa-bg-mini.t-bien .fa-bg-deco, .fa-bg-mini.t-hoang-hon .fa-bg-deco { transform: none; width: 18px; height: 9px; }
.fa-bg-mini.t-bien .fa-bg-deco:nth-child(n+4), .fa-bg-mini.t-hoang-hon .fa-bg-deco:nth-child(n+4) { display: none; }

@media (max-width: 767.98px) { .fa-bg.t-tet::after { display: none; } }
@media (max-width: 575.98px) {
  .fa-bg-grid { grid-template-columns: repeat(2, 1fr); gap: .65rem; }
  .fa-bgcard-body small { display: none; }
  .fa-bg-savebar { border-radius: 18px; }
}
@media (prefers-reduced-motion: reduce) {
  .fa-bg .fa-bg-deco, .fa-bg::before, .fa-bg::after { animation: none !important; }
  .fa-bg .fa-bg-deco { display: none; }
  .fa-bgcard, .fa-bgcard-check { transition: none; }
}