:root{
  --card-bg:#0f1720;      /* card backgrounds */
  --bg:#0b0f14;           /* page background */
  --surface:#0b1220;      /* inner surfaces like preview box */
  --border:#1f2a36;       /* borders */
  --accent:#1fb6ff;       /* primary accent */
  --muted:#9aa6b2;        /* muted text */
  --text:#e6eef6;         /* main text */
  font-family:system-ui,-apple-system,Segoe UI,Roboto,"Helvetica Neue",Arial;
}

/* title bar (fixed to top) */
.title-bar{
  position:fixed;
  top:18px;
  left:50%;
  transform:translateX(-50%);
  z-index:60;
  display:block;
  text-align:center;
  font-weight:700;
  color:var(--text);
  background:linear-gradient(180deg, rgba(255,255,255,0.02), rgba(255,255,255,0.01));
  border:1px solid var(--border);
  padding:10px 14px;
  border-radius:10px;
  max-width:980px;
  width:calc(100% - 36px);
  box-shadow:0 6px 18px rgba(0,0,0,0.5);
  font-size:15px;
  letter-spacing:0.2px;
}
*{box-sizing:border-box}
html,body,#app{height:100%}
body{
  margin:0;
  background:var(--bg);
  color:var(--text);
  display:flex;
  align-items:flex-start;
  justify-content:center;
  padding:18px;
  padding-top:84px; /* reserve space for fixed title bar */
  -webkit-font-smoothing:antialiased;
  -moz-osx-font-smoothing:grayscale;
}
main{width:100%;max-width:980px}
form{display:grid;gap:12px}

/* layout */
.row{display:flex;gap:12px}
.card{
  background:var(--card-bg);
  border:1px solid var(--border);
  padding:12px;
  border-radius:8px;
  flex:1;
  color:var(--text);
}
.card h3{margin:0 0 8px 0;font-size:15px}
input,textarea{width:100%;padding:8px;border:1px solid var(--border);border-radius:6px;font-size:14px;margin-bottom:8px;background:transparent;color:var(--text)}
textarea{min-height:64px;resize:vertical}
.meta{display:flex;gap:8px;flex-wrap:wrap}
.meta label{flex:1;display:flex;flex-direction:column;font-size:13px;color:var(--muted)}
.meta input{margin-top:6px;color:var(--text);background:transparent}

#items{margin-top:6px}
.item-row{display:flex;gap:8px;align-items:center;margin-bottom:8px}
.item-row .desc{flex:1}
.item-row .qty{width:72px}
.item-row .rate{width:100px}
.item-row .line-total{width:88px;text-align:right;padding-right:6px;font-weight:600;color:var(--text)}
.item-row .remove{background:transparent;border:0;color:#ff8b8b;font-size:18px;line-height:1;padding:6px;cursor:pointer}

.items-controls{display:flex;justify-content:flex-start;padding-top:6px}
#add-item{background:transparent;border:1px solid var(--border);padding:8px 10px;border-radius:6px;cursor:pointer;color:var(--text)}

.totals{display:flex;gap:12px;align-items:flex-start}
.totals label{flex:1}
.totals textarea{height:76px;background:transparent;color:var(--text)}
.calc{width:260px;background:var(--surface);border:1px solid var(--border);padding:8px;border-radius:6px}
.calc div{display:flex;justify-content:space-between;padding:6px 0}
.calc input{width:64px;padding:4px;background:transparent;color:var(--text);border:1px solid var(--border)}

.actions{display:flex;gap:12px;justify-content:flex-end}
.actions button{padding:10px 14px;border-radius:8px;border:0;background:var(--accent);color:#06202a;cursor:pointer;font-weight:600}
#preview-btn{background:linear-gradient(180deg,var(--accent),#0aa2ff)}
#print-btn{background:linear-gradient(180deg,#14a3ff,#0b8be0)}

/* printable invoice styles (used for generated html) */
.invoice{
  width:800px;
  font-family:inherit;
  color:var(--text);
  padding:28px;
  background:linear-gradient(180deg,#081018,#071016);
}
.invoice header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:18px}
.invoice .addresses{display:flex;gap:24px}
.invoice h1{margin:0;font-size:22px;color:var(--text)}
.table{width:100%;border-collapse:collapse;margin-top:12px}
.table th,.table td{border-bottom:1px solid #132029;padding:8px;text-align:left;color:var(--text)}
.table th{background:#071219;color:var(--muted)}
.right{text-align:right}
.small{color:var(--muted);font-size:13px}

/* preview modal (in-page) */
#print-area{position:fixed;inset:0;display:flex;align-items:center;justify-content:center;pointer-events:none}
#print-area[aria-hidden="false"]{pointer-events:auto}
.preview-backdrop{position:fixed;inset:0;background:linear-gradient(rgba(3,6,10,0.6),rgba(3,6,10,0.6));display:flex;align-items:center;justify-content:center;padding:20px}
.preview-box{width:100%;max-width:900px;height:90vh;background:var(--surface);border-radius:10px;overflow:hidden;display:flex;flex-direction:column;box-shadow:0 8px 30px rgba(0,0,0,0.6)}
.preview-toolbar{display:flex;justify-content:space-between;padding:8px;background:transparent;border-bottom:1px solid var(--border)}
.preview-toolbar button{background:transparent;border:0;padding:8px 10px;border-radius:6px;cursor:pointer;color:var(--text)}
.preview-frame{flex:1;border:0;width:100%;height:100%;background:#081018}

/* responsive for smaller screens */
@media (max-width:760px){
  .row{flex-direction:column}
  .calc{width:100%}
  .invoice{width:100%;padding:18px}
}