/* ============ 基础层：变量 / 重置 / 3D 背景层 ============ */

/* ============ 幻音图境 · 3D 视觉设计系统 ============ */
:root{
  --bg:#07070f; --bg2:#0d0d1d; --panel:rgba(20,20,40,.72); --panel-solid:#141428;
  --line:rgba(140,140,255,.16); --line2:rgba(140,140,255,.28);
  --txt:#e8e9f5; --txt2:#9a9ab8; --txt3:#5d5d78;
  --cyan:#5eead4; --blue:#60a5fa; --violet:#a78bfa; --pink:#f472b6; --gold:#fbbf24;
  --grad:linear-gradient(120deg,#5eead4,#60a5fa 40%,#a78bfa 70%,#f472b6);
  --grad2:linear-gradient(120deg,#f472b6,#a78bfa 50%,#60a5fa);
  --glow:0 0 24px rgba(96,165,250,.35);
  --r:14px; --r2:20px;
  --font:"PingFang SC","Microsoft YaHei","Segoe UI",system-ui,sans-serif;
}
*{margin:0;padding:0;box-sizing:border-box}
html{scroll-behavior:smooth}
body{background:var(--bg);color:var(--txt);font-family:var(--font);overflow-x:hidden;min-height:100vh}
a{color:inherit;text-decoration:none}
button{font-family:var(--font);cursor:pointer;border:none;background:none;color:inherit}
input,textarea,select{font-family:var(--font)}
::-webkit-scrollbar{width:9px;height:9px}
::-webkit-scrollbar-thumb{background:#2a2a4a;border-radius:5px}
::-webkit-scrollbar-track{background:transparent}

/* ---- 3D 背景层 ---- */
#bg3d{position:fixed;inset:0;z-index:0;display:block;transition:opacity .5s}
/* 性能降级：着色器关闭时显示主题静态渐变 */
body.bg-static #bg3d{background:var(--grad);opacity:1 !important}
body.bg-static #bg3d::after{content:"";position:absolute;inset:0;background:radial-gradient(ellipse at 30% 20%,rgba(255,255,255,.14),transparent 55%)}
#vignette{position:fixed;inset:0;z-index:1;pointer-events:none;
  background:radial-gradient(ellipse at 50% 0%,transparent 40%,rgba(5,5,15,.55) 100%)}