/* ═══════════════════════════════════════════
   NAV — 顶部导航栏 + 音乐控制 + 音量弹窗
   修改导航外观、音乐按钮、音量滑块时改此文件
   ═══════════════════════════════════════════ */

nav{position:fixed;top:0;left:0;right:0;z-index:300;padding:15px 34px;display:flex;justify-content:space-between;align-items:center;background:linear-gradient(to bottom,rgba(5,5,8,.97),transparent);backdrop-filter:blur(14px);border-bottom:1px solid rgba(201,168,76,.14);}
.nav-logo{font-family:'Cinzel Decorative',serif;font-size:1.1rem;color:var(--accent-gold);text-shadow:0 0 18px var(--card-glow);letter-spacing:2px;cursor:pointer;}
.nav-right{display:flex;align-items:center;gap:8px;}
.nav-btn{background:none;border:1px solid rgba(201,168,76,.22);color:var(--pale-lavender);padding:6px 13px;border-radius:20px;cursor:pointer;font-family:'Noto Sans SC',sans-serif;font-size:.73rem;letter-spacing:1px;transition:all .3s;}
.nav-btn:hover,.nav-btn.active{border-color:var(--accent-gold);color:var(--accent-gold);background:rgba(201,168,76,.09);box-shadow:0 0 12px rgba(201,168,76,.18);}

/* 音乐控制区 */
#musicControl{position:relative;flex-shrink:0;}
#musicToggle{background:none;border:1.5px solid rgba(201,168,76,.4);color:var(--accent-gold);width:36px;height:36px;border-radius:50%;cursor:pointer;font-size:1rem;display:flex;align-items:center;justify-content:center;transition:color .3s,border-color .3s,box-shadow .3s;position:relative;overflow:visible;}
#musicToggle:hover{background:rgba(201,168,76,.1);box-shadow:0 0 14px rgba(201,168,76,.3);}
#musicToggle.playing{animation:musicPulse 2.5s ease-in-out infinite;}
#musicToggle.muted{color:#666;border-color:rgba(130,130,130,.35);box-shadow:none !important;animation:none !important;}
#musicToggle .note-icon{position:relative;z-index:1;font-size:1rem;transition:color .3s;}
#musicToggle.muted .note-icon{color:#595959;}
#musicToggle .slash{position:absolute;top:50%;left:50%;width:32px;height:2.5px;background:linear-gradient(90deg,transparent 0%,#888 20%,#888 80%,transparent 100%);border-radius:2px;transform:translate(-50%,-50%) rotate(-42deg);transform-origin:center;opacity:0;transition:opacity .2s;pointer-events:none;z-index:2;}
#musicToggle .slash::before,#musicToggle .slash::after{content:'';position:absolute;top:50%;transform:translateY(-50%);width:7px;height:7px;border-radius:50%;background:var(--deep-black);}
#musicToggle .slash::before{left:-4px;}
#musicToggle .slash::after{right:-4px;}
#musicToggle.muted .slash{opacity:1;}

/* 音量弹窗 — 出现在按钮正下方 */
#volumePopup{position:absolute;top:calc(100% + 8px);right:0;background:rgba(8,4,20,.95);border:1px solid rgba(201,168,76,.3);border-radius:12px;padding:12px 14px;display:none;flex-direction:column;align-items:center;gap:8px;z-index:500;box-shadow:0 8px 28px rgba(0,0,0,.6);backdrop-filter:blur(12px);min-width:36px;}
#volumePopup.open{display:flex;}
#volumePopup label{font-size:.58rem;color:rgba(201,168,76,.7);letter-spacing:.5px;}
#volumeSlider{-webkit-appearance:none;appearance:none;width:90px;height:4px;border-radius:2px;background:linear-gradient(to right,var(--accent-gold) var(--vol,60%),rgba(255,255,255,.15) var(--vol,60%));outline:none;cursor:pointer;}
#volumeSlider::-webkit-slider-thumb{-webkit-appearance:none;width:14px;height:14px;border-radius:50%;background:var(--accent-gold);box-shadow:0 0 8px var(--card-glow);cursor:pointer;}
#volumeSlider::-moz-range-thumb{width:14px;height:14px;border-radius:50%;background:var(--accent-gold);border:none;cursor:pointer;}

/* 音乐模式切换按钮 */
#musicModeBtn{background:none;border:1px solid rgba(201,168,76,.2);color:rgba(212,200,232,.55);height:34px;border-radius:17px;padding:0 10px;cursor:pointer;font-size:.65rem;letter-spacing:.5px;transition:all .3s;white-space:nowrap;flex-shrink:0;}
#musicModeBtn:hover{border-color:rgba(201,168,76,.5);color:var(--accent-gold);}
#musicModeBtn.rain-mode{border-color:rgba(100,180,255,.45);color:rgba(130,200,255,.8);}
#musicModeBtn.calm-mode{border-color:rgba(100,200,150,.45);color:rgba(130,220,170,.8);}

/* 音乐可视化条 */
#musicViz{display:flex;align-items:flex-end;gap:2px;height:16px;opacity:0;transition:opacity .5s;}
#musicViz.visible{opacity:.7;}
#musicViz .vb{width:3px;border-radius:2px;background:var(--accent-gold);animation:vizBar var(--vd) ease-in-out infinite alternate;}