:root {
    --bg:         #0f1117;
    --surface:    #1a1d27;
    --surface2:   #252837;
    --border:     #2e3148;
    --text:       #e2e8f0;
    --text-dim:   #94a3b8;
    --yellow:     #f59e0b;
    --yellow-dim: #78350f;
    --blue:       #3b82f6;
    --blue-dim:   #1e3a5f;
    --green:      #22c55e;
    --green-dim:  #14532d;
    --red:        #ef4444;
    --red-dim:    #7f1d1d;
    --purple:     #a78bfa;
    --orange:     #fb923c;
    --radius:     12px;
    --gap:        16px;
  }
  * { box-sizing: border-box; margin: 0; padding: 0; }
  body {
    background: var(--bg);
    color: var(--text);
    font-family: 'Segoe UI', system-ui, sans-serif;
    min-height: 100vh;
  }

  /* ── Header ── */
  header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 20px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    position: sticky;
    top: 0;
    z-index: 10;
    gap: 12px;
  }
  header h1 { font-size: 1.15rem; font-weight: 700; color: var(--yellow); }
  .header-right {
    display: flex; align-items: center; gap: 10px; flex-shrink: 0;
  }
  #last-update {
    font-size: 0.75rem;
    color: var(--text-dim);
    white-space: nowrap;
  }
  #last-update.stale { color: var(--orange); }
  #refresh-btn {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: 6px;
    color: var(--text);
    cursor: pointer;
    font-size: 1rem;
    padding: 4px 9px;
    transition: all .2s;
    line-height: 1;
  }
  #refresh-btn:hover { border-color: var(--blue); color: var(--blue); }
  #refresh-btn.spinning { animation: spin .6s linear infinite; }
  @keyframes spin { to { transform: rotate(360deg); } }
  #clock { color: var(--text-dim); font-size: 0.88rem; font-variant-numeric: tabular-nums; }
  #health-dot {
    width: 10px; height: 10px; border-radius: 50%;
    background: var(--text-dim); display: inline-block; flex-shrink: 0;
  }
  #health-dot.ok   { background: var(--green); }
  #health-dot.warn { background: var(--yellow); animation: pulse 2s infinite; }
  #health-dot.error{ background: var(--red);    animation: pulse 1s infinite; }
  @keyframes pulse { 0%,100%{opacity:1} 50%{opacity:.3} }

  /* ── Navigation ── */
  nav {
    display: flex; gap: 4px;
    padding: 10px 20px;
    background: var(--surface);
    border-bottom: 1px solid var(--border);
    flex-wrap: wrap;
  }
  nav button {
    padding: 5px 14px;
    border: 1px solid var(--border);
    border-radius: 6px;
    background: transparent;
    color: var(--text-dim);
    cursor: pointer;
    font-size: 0.82rem;
    transition: all .2s;
  }
  nav button.active { background: var(--blue); border-color: var(--blue); color: #fff; }
  nav button:hover:not(.active) { border-color: var(--blue); color: var(--text); }

  /* ── Main ── */
  main { padding: var(--gap); max-width: 1400px; margin: 0 auto; padding-bottom: 48px; }
  .section { margin-bottom: 18px; }
  .section-title {
    font-size: 0.72rem; text-transform: uppercase;
    letter-spacing: .08em; color: var(--text-dim); margin-bottom: 10px;
  }

  /* ── Card Grid ── */
  .card-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(190px,1fr)); gap: var(--gap); }
  .card-grid-3 { grid-template-columns: repeat(3,1fr); }
  .card-grid-4 { grid-template-columns: repeat(4,1fr); }
  .card-grid-5 { grid-template-columns: repeat(5,1fr); }
  @media(max-width:900px){ .card-grid-3,.card-grid-4,.card-grid-5{ grid-template-columns: repeat(2,1fr); } }
  @media(max-width:520px){ .card-grid-3,.card-grid-4,.card-grid-5{ grid-template-columns: repeat(2,1fr); } }

  /* ── Card ── */
  .card {
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 16px 18px;
    transition: border-color .2s;
  }
  .card:hover { border-color: #4e5a80; }
  .card-label { font-size: 0.72rem; color: var(--text-dim); text-transform: uppercase; letter-spacing:.06em; margin-bottom:5px; }
  .card-value { font-size: 1.9rem; font-weight: 700; line-height: 1; }
  .card-sub   { font-size: 0.78rem; color: var(--text-dim); margin-top: 4px; }
  .card-unit  { font-size: 0.95rem; font-weight: 400; margin-left: 3px; color: var(--text-dim); }
  .card.small { padding: 11px 14px; }
  .card.small .card-value { font-size: 1.25rem; }
  .card.small .card-label { font-size: 0.68rem; }
  .card.yellow .card-value { color: var(--yellow); }
  .card.blue   .card-value { color: var(--blue);   }
  .card.green  .card-value { color: var(--green);  }
  .card.red    .card-value { color: var(--red);    }
  .card.purple .card-value { color: var(--purple); }
  .card.orange .card-value { color: var(--orange); }
  .card.batt-charging    .card-value { color: var(--green);  }
  .card.batt-discharging .card-value { color: var(--orange); }
  .card.grid-feed .card-value { color: var(--green); }
  .card.grid-draw .card-value { color: var(--red);   }
  .card.grid-idle .card-value { color: var(--text-dim); }
  .card.dim   .card-value { color: var(--text-dim); }

  /* ── Chart ── */
  .chart-card {
    background: var(--surface); border: 1px solid var(--border);
    border-radius: var(--radius); padding: 14px;
  }
  .chart-card canvas { max-height: 240px; }
  .chart-title { font-size: 0.78rem; color: var(--text-dim); margin-bottom: 10px; text-transform: uppercase; letter-spacing:.06em; }

  /* ── Tabs ── */
  .tab-content { display: none; }
  .tab-content.active { display: block; }

  /* ── Compare ── */
  .compare-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--gap); }
  @media(max-width:600px){ .compare-grid { grid-template-columns: 1fr; } }

  /* ── Tagesverlauf Grid: auf Mobile einspaltig ── */
  .tagesverlauf-grid { display: grid; grid-template-columns: 1fr 1fr; gap: var(--gap); }
  @media(max-width:768px) {
    .tagesverlauf-grid { grid-template-columns: 1fr !important; }
    #chart-today-power { width: 100% !important; overflow: visible !important; }
  }

  /* ── Status bar ── */
  #status-bar {
    font-size: 0.72rem; color: var(--text-dim);
    padding: 5px 20px; background: var(--surface);
    border-top: 1px solid var(--border);
    position: fixed; bottom:0; left:0; right:0;
    white-space: nowrap; overflow: hidden; text-overflow: ellipsis;
  }
  #status-bar.error-bar { color: var(--orange); }

  .stale-overlay {
    font-size: 0.7rem; color: var(--orange);
    padding: 2px 8px; background: rgba(251,146,60,.12);
    border: 1px solid rgba(251,146,60,.3); border-radius: 4px;
    display: none;
  }
  .stale-overlay.visible { display: inline-block; }