:root{
  --bg-1: linear-gradient(135deg,#0f1724 0%,#0b1220 100%);
  --card: #0b1226;
  --accent: #7c3aed; /* violet */
  --accent-2: #06b6d4; /* teal */
  --muted: #9aa4b2;
  --title-size: 20px;
  --name-size: 12px;
  --title-glow: 0 6px 18px rgba(124,58,237,0.18);
}

*{box-sizing:border-box}
html,body{height:100%;}
body{
  margin:0;
  font-family: 'Inter', system-ui, -apple-system, 'Segoe UI', Roboto, 'Helvetica Neue', Arial;
  background: var(--bg-1);
  color:#e6eef8;
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}

.page-bg{min-height:100vh;display:flex;flex-direction:column}
.top-bar{padding:18px 24px;border-bottom:1px solid rgba(255,255,255,0.04)}
.brand{display:flex;flex-direction:column;align-items:center;justify-content:center;text-align:center}
.brand h1{font-size:20px;margin:0;font-weight:600}
.brand .author{display:block;color:var(--muted);font-size:12px;margin-top:4px}

/* Highlighted project title and author */
.project-title{
  font-family: 'Orbitron', Inter, system-ui, sans-serif;
  font-size:var(--title-size);
  font-weight:900;
  margin:0;
  background: linear-gradient(90deg,var(--accent),var(--accent-2));
  -webkit-background-clip: text;
  background-clip: text;
  color: transparent;
  letter-spacing:0.6px;
  text-shadow: var(--title-glow);
}

.author-name{
  display:block;
  margin-top:6px;
  font-family: 'Orbitron', Inter, system-ui, sans-serif;
  font-size:var(--name-size);
  font-weight:600;
  color: var(--accent-2);
  text-transform:uppercase;
  opacity:0.98;
  letter-spacing:0.9px;
}

.center{flex:1;display:flex;align-items:center;justify-content:center;padding:28px}
.calculator{
  width:320px;
  max-width:95vw;
  background: linear-gradient(180deg, rgba(255,255,255,0.03), rgba(255,255,255,0.01));
  border-radius:14px;
  box-shadow: 0 10px 30px rgba(2,6,23,0.6);
  padding:18px;
}

.display{
  background: rgba(255,255,255,0.03);
  color:#f8fafc;
  text-align:right;
  padding:18px 14px;
  font-size:28px;
  border-radius:8px;
  min-height:56px;
  margin-bottom:12px;
  overflow:hidden;
  white-space:nowrap;
  text-overflow:ellipsis;
}

.keys{display:grid;grid-template-columns:repeat(4,1fr);gap:10px}
.key{
  background: rgba(255,255,255,0.03);
  border:1px solid rgba(255,255,255,0.04);
  color: #e6eef8;
  padding:14px 8px;
  border-radius:8px;
  font-size:18px;
  cursor:pointer;
  transition:transform .08s ease, background .12s ease;
}
.key:active{transform:translateY(1px)}
.key:hover{background: rgba(255,255,255,0.05)}
.key--op{background:linear-gradient(90deg,var(--accent),var(--accent-2));color:white;border:none}
.key--enter{grid-row:4 / span 2;background:linear-gradient(90deg,#06b6d4,#7c3aed);grid-column:4}
.key--wide{grid-column:1 / span 2}

.footer{padding:12px 18px;text-align:center;color:var(--muted);font-size:13px}

@media (min-width:600px){
  .calculator{width:380px}
  .display{font-size:32px}
}

/* small accessibility focus styles */
.key:focus{outline:3px solid rgba(124,58,237,0.18);outline-offset:2px}