/* Reset & Variables */
*{box-sizing:border-box;margin:0;padding:0;}
:root{
  --bg:#0f1724;
  --card:#0b1220cc;
  --accent:#6ee7b7;
  --accent-2:#7c9cff;
  --muted:#9aa6bf;
  --btn-bg: rgba(255,255,255,0.03);
  --shadow:0 10px 30px rgba(3,7,18,0.6);
  font-family: 'Inter', sans-serif;
}
html,body{height:100%;background:var(--bg);display:flex;align-items:center;justify-content:center;overflow:hidden;}
body{position:relative;}

/* Moving background elements */
#bgCanvas{position:fixed;top:0;left:0;width:100%;height:100%;z-index:0;}

/* App container */
.app{width:100%;max-width:960px;display:flex;flex-direction:column;gap:16px;z-index:1;position:relative;animation:glideFade 0.8s ease forwards;}
@keyframes glideFade{0%{opacity:0;transform:translateY(-40px);}100%{opacity:1;transform:translateY(0);}}

/* Header */
.app-header{display:flex;justify-content:space-between;align-items:center;margin-bottom:6px;transition:all .5s ease;}
.logo{font-weight:700;font-size:22px;color:var(--accent);letter-spacing:1px;text-shadow:0 6px 18px rgba(110,231,183,0.08);transition:all .5s ease;}
.mode-toggle{display:flex;align-items:center;gap:12px;color:var(--muted);font-size:14px;transition:all .5s ease;}

/* Toggle */
.switch{position:relative;display:inline-block;width:50px;height:28px;}
.switch input{display:none;}
.slider{position:absolute;cursor:pointer;top:0;left:0;right:0;bottom:0;background:rgba(255,255,255,0.1);transition:.4s;border-radius:34px;border:1px solid rgba(255,255,255,0.1);}
.slider:before{position:absolute;content:"";height:22px;width:22px;left:3px;bottom:3px;background:white;transition:.4s;border-radius:50%;}
input:checked + .slider{background:linear-gradient(90deg,var(--accent),var(--accent-2));}
input:checked + .slider:before{transform:translateX(22px);}

/* Calculator card */
.calculator-card{background:var(--card);border-radius:18px;padding:20px;box-shadow:var(--shadow);border:1px solid rgba(255,255,255,0.03);backdrop-filter:blur(8px);transition:all .5s ease;position:relative;overflow:hidden;min-height:580px;display:flex;flex-direction:column;align-items:center;width:450px;}
.calculator-card.advanced-active{width:680px;transition:width 0.5s ease;}

/* Display */
.display-panel{background:rgba(255,255,255,0.05);padding:14px;border-radius:12px;margin-bottom:12px;display:flex;flex-direction:column;gap:6px;border:1px solid rgba(255,255,255,0.04);z-index:1;position:relative;width:100%;transition:all .5s ease;}
.display{width:100%;font-size:clamp(20px,2.8vw,32px);background:transparent;border:none;color:#f4fbff;text-align:right;padding:8px 10px;transition:all .2s ease;}
.history{color:var(--muted);font-size:13px;min-height:18px;opacity:0.9;}

/* Controls layout */
.controls{display:flex;gap:12px;width:100%;z-index:1;position:relative;justify-content:center;transition:all .5s ease;}
.left-column{flex:2;display:flex;flex-direction:column;gap:8px;transition:all .5s ease;}
.right-column{flex:1;background:rgba(255,255,255,0.05);padding:12px;border-radius:12px;display:flex;flex-direction:column;gap:12px;transition:all .5s ease;display:none;}

/* Buttons */
.row{display:flex;gap:10px;}
.btn{flex:1;padding:14px;border-radius:12px;background:var(--btn-bg);border:1px solid rgba(255,255,255,0.06);color:white;font-size:16px;cursor:pointer;transition:all .3s ease;box-shadow:0 6px 16px rgba(2,6,18,0.5);display:flex;align-items:center;justify-content:center;}
.btn:hover{background:rgba(255,255,255,0.12);}
.btn:active{transform:translateY(2px) scale(.97);}
.btn.small{padding:14px;font-size:16px;}
.btn.op{background:rgba(255,255,255,0.03);}
.btn.accent{background:linear-gradient(90deg,var(--accent),var(--accent-2));color:white;font-weight:700;box-shadow:0 8px 20px rgba(110,231,183,0.3);}
.btn.equal{background:linear-gradient(90deg,#ffd97a,#ff9fb5);color:white;font-weight:700;}
.btn.zero{flex:2;}

/* Advanced */
.advanced.active{display:flex;flex-direction:column;transition:all .5s ease;}
.advanced .row{margin-bottom:6px;}

/* History inside advanced */
.advanced .history-box{background:rgba(255,255,255,0.03);border-radius:10px;padding:14px 14px;min-height:120px;max-height:120px;overflow-y:auto;font-size:13px;color:var(--muted);transition:all .5s ease;}
.advanced .history-box::-webkit-scrollbar{width:6px;}
.advanced .history-box::-webkit-scrollbar-thumb{background:rgba(110,231,183,0.4);border-radius:3px;}
.history-title{font-weight:600;margin-bottom:6px;color:var(--muted);}
.history-list{list-style:none;display:flex;flex-direction:column;gap:6px;max-height:120px;overflow-y:auto;padding:0;margin:0;}
.history-list li{padding:10px 14px;border-radius:6px;background: rgba(255,255,255,0.01);cursor:pointer;transition:all .12s ease;}
.history-list li:hover{background: rgba(255,255,255,0.05);}

/* Footer */
.app-footer{color:var(--muted);font-size:14px;text-align:center;margin-top:8px;}