:root{
    --bg: #0f172a;            /* slate-900 */
    --panel: #111827;         /* gray-900 */
    --panel-2: #0b1222;       /* deep */
    --accent: #8b5cf6;        /* violet-500 */
    --accent-2:#22d3ee;       /* cyan-400 */
    --text: #e5e7eb;          /* gray-200 */
    --muted:#9ca3af;          /* gray-400 */
    --grid:#1f2937;           /* gray-800 */
    --today:#10b981;          /* emerald-500 */
    --sel:#f59e0b;            /* amber-500 */
    --danger:#ef4444;         /* red-500 */
    --shadow: 0 10px 25px rgba(0,0,0,.4), inset 0 0 0 1px rgba(255,255,255,.04);
    --radius: 18px;
    --gap: 14px;
  }

  *{box-sizing:border-box}
  html,body{height:100%}
  body{
    margin:0;
    font-family: ui-sans-serif, system-ui, -apple-system, Segoe UI, Roboto, Helvetica, Arial, "Apple Color Emoji","Segoe UI Emoji";
    background:
      radial-gradient(1200px 600px at 10% -10%, rgba(139,92,246,.18), transparent 70%),
      radial-gradient(900px 400px at 110% 20%, rgba(34,211,238,.14), transparent 65%),
      linear-gradient(180deg, #0b1023 0%, #0f172a 100%);
    color:var(--text);
    display:grid;
    place-items:center;
    padding:20px;
  }

  .app{
    width:min(1100px, 100%);
  }

  .toolbar{
    display:flex;
    flex-wrap:wrap;
    gap: var(--gap);
    align-items:center;
    justify-content:space-between;
    margin-bottom:16px;
  }
  .group{
    display:flex;
    gap: var(--gap);
    align-items:center;
  }

  .title{
    font-size: clamp(1.1rem, 2.4vw, 1.6rem);
    font-weight:700;
    letter-spacing:.3px;
    display:flex; align-items:center; gap:10px;
  }
  .title small{
    font-weight:500; color:var(--muted); letter-spacing:.2px;
  }

  .control, select, input[type="month"]{
    background: linear-gradient(180deg, #0e152d 0%, #0b1222 100%);
    color:var(--text);
    border:1px solid rgba(255,255,255,.06);
    border-radius:12px;
    padding:10px 14px;
    font-weight:600;
    letter-spacing:.2px;
    box-shadow: var(--shadow);
    cursor:pointer;
    transition: transform .12s ease, box-shadow .2s ease, border-color .2s ease;
    user-select:none;
  }
  .control:hover{ transform: translateY(-1px); border-color: rgba(255,255,255,.12); }
  .control:active{ transform: translateY(0); }
  .control.accent{ background: linear-gradient(180deg, #4630b5, #7c3aed); }
  .control.ghost{ background: #0b1222; }
  .control.warn{ background: linear-gradient(180deg, #14532d, #065f46); }
  .control.danger{ background: linear-gradient(180deg, #7f1d1d, #991b1b); }

  /* Flip container */
  .calendar-shell{
    perspective: 1600px;
  }
  .flip{
    position:relative;
    width:100%;
    background: radial-gradient(120% 160% at 10% -10%, rgba(139,92,246,.08), transparent 60%),
                linear-gradient(180deg, #0b1222, #0b1222);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow:hidden;
  }
  .flip-inner{
    position:relative;
    transform-style: preserve-3d;
    transition: transform .68s cubic-bezier(.22,.75,.2,1);
    min-height: 560px;
  }
  @media (max-width: 640px){
    .flip-inner{ min-height:520px; }
  }
  .face{
    position:absolute; inset:0;
    backface-visibility: hidden;
    padding: 18px;
    display:flex; flex-direction:column; gap:18px;
  }
  .face.back{ transform: rotateY(180deg); }

  /* Calendar grid */
  .weekdays, .grid{
    display:grid;
    grid-template-columns: repeat(7, 1fr);
    gap: 8px;
  }
  .weekdays div{
    text-align:center;
    font-size:.78rem;
    color:var(--muted);
    padding:8px 0;
    border-radius:10px;
    background: linear-gradient(180deg, #0f1a36, #0c152b);
    border:1px solid rgba(255,255,255,.04);
  }
  .day{
    border-radius:14px;
    border:1px solid rgba(255,255,255,.06);
    background: linear-gradient(180deg, #0f1a36, #0b1222);
    min-height: 84px;
    display:flex; flex-direction:column;
    padding:10px;
    position:relative;
    transition: transform .12s ease, border-color .2s ease, background .2s ease;
    cursor:pointer;
    outline:none;
  }
  .day:hover{ transform: translateY(-2px); border-color: rgba(255,255,255,.12)}
  .day:focus-visible{ box-shadow: 0 0 0 3px rgba(139,92,246,.45) }
  .day.other-month{ opacity:.45 }
  .day .num{
    font-weight:700; font-size:.95rem; letter-spacing:.25px;
    display:flex; gap:8px; align-items:center;
  }
  .dot{
    width:6px; height:6px; border-radius:50%;
    background: var(--accent-2);
    margin-left:6px;
  }
  .day .note{
    font-size:.78rem; color:var(--muted); margin-top:6px;
    line-height:1.25; max-height: 2.55em; overflow:hidden;
    text-overflow: ellipsis;
  }
  .day.today{ border-color: rgba(16,185,129,.6) }
  .badge{
    display:inline-flex; align-items:center; gap:6px;
    font-size:.72rem; font-weight:700; color:#052e2b;
    background: linear-gradient(180deg, #34d399, #10b981);
    padding:3px 8px; border-radius:999px;
  }
  .day.selected{
    outline: 2px solid var(--sel);
  }

  /* Footer */
  .footer{
    display:flex; justify-content:space-between; align-items:center;
    gap:12px; flex-wrap:wrap;
    padding: 12px 16px;
    border-top:1px dashed rgba(255,255,255,.08);
    background: linear-gradient(180deg, rgba(255,255,255,.02), transparent);
    border-bottom-left-radius: var(--radius);
    border-bottom-right-radius: var(--radius);
  }
  .meta{ color:var(--muted); font-size:.9rem }
  .kbd{
    background:#0b1222; border:1px solid rgba(255,255,255,.12);
    border-bottom-width:3px;
    padding: 2px 6px; border-radius:6px; font-weight:700; font-size:.8rem;
  }

  /* Select styles */
  .pickers{
    display:flex; gap:10px; align-items:center; flex-wrap:wrap;
  }
  select{
    appearance:none;
    padding-right:36px;
    background-image:
      linear-gradient(45deg, transparent 50%, #9ca3af 50%),
      linear-gradient(135deg, #9ca3af 50%, transparent 50%),
      linear-gradient(to right, transparent, transparent);
    background-position:
      calc(100% - 18px) 50%,
      calc(100% - 12px) 50%,
      100% 0;
    background-size:6px 6px, 6px 6px, 2.5em 2.5em;
    background-repeat:no-repeat;
  }

  /* Small helper tooltip */
  .tip{
    font-size:.8rem; color:var(--muted);
  }