* {
    box-sizing: border-box;
}

html, body {
    font-family: Arial, Helvetica, sans-serif;
    margin: 0;
    padding: 0;
    background-color: #f0f2f5;
}

.hidden {
    display: none !important;
}

.topnav {
    overflow: hidden;
    background-color: #0A1128;
    padding: 0 20px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.topnav h1 {
    font-size: 1.5rem;
    color: white;
    margin: 0;
    padding: 16px 0;
    text-align: center;
}

.content {
    padding: 24px 20px;
    max-width: 1100px;
    margin: 0 auto;
}

.connection-card {
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.07);
    padding: 20px 24px;
    margin-bottom: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-wrap: wrap;
    gap: 16px;
}

.ble-status {
    display: flex;
    align-items: center;
    gap: 8px;
    background: #f1f1f1;
    border-radius: 20px;
    padding: 6px 14px;
    font-size: 0.85rem;
    color: #555;
}

.ble-dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background-color: #d13a30;
    transition: background-color 0.4s;
}

.ble-dot.connected {
    background-color: #24af37;
}

button {
    color: white;
    padding: 11px 20px;
    border: none;
    cursor: pointer;
    border-radius: 6px;
    font-size: 0.9rem;
    font-weight: 600;
    transition: opacity 0.15s, transform 0.1s;
}

button:hover {
    opacity: 0.88;
}

button:active {
    transform: scale(0.97);
}

.connectButton    { background-color: #24af37; }
.disconnectButton { background-color: #d13a30; }

.sensor-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 16px;
    margin-bottom: 24px;
}

.sensor-card {
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.07);
    padding: 20px 24px;
    text-align: center;
}

.sensor-card .sensor-icon {
    font-size: 2rem;
    margin-bottom: 6px;
    display: flex;
    align-items: center;
    justify-content: center;
    height: 2.4rem;
}

.sensor-card .sensor-label {
    font-size: 1.1rem;
    color: #999;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 6px;
}

.sensor-card .sensor-value {
    font-size: 2.4rem;
    font-weight: 700;
    line-height: 1;
    margin-bottom: 4px;
}

.sensor-card .sensor-unit {
    font-size: 1rem;
    font-weight: 400;
    color: #888;
}

.sensor-card .sensor-timestamp {
    font-size: 0.75rem;
    color: #bbb;
    margin-top: 8px;
}

.sensor-card.temp  .sensor-value { color: #e07b3a; }
.sensor-card.hum   .sensor-value { color: #3a90c4; }
.sensor-card.press .sensor-value { color: #7c5cbf; }

.unit-toggle {
    display: inline-flex;
    background: #f1f1f1;
    border-radius: 50px;
    padding: 3px;
    margin-top: 10px;
}

.unit-btn {
    padding: 4px 14px;
    font-size: 0.78rem;
    font-weight: 600;
    border: none;
    border-radius: 50px;
    cursor: pointer;
    background: transparent;
    color: #666;
    transition: all 0.2s;
}

.unit-btn.active {
    background: #0A1128;
    color: white;
}

.charts-section {
    display: flex;
    flex-direction: column;
    gap: 20px;
    margin-bottom: 24px;
}

.chart-card {
    background: white;
    border-radius: 10px;
    box-shadow: 0 2px 8px rgba(0,0,0,0.07);
    padding: 20px 24px;
}

.chart-card-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    margin-bottom: 16px;
    flex-wrap: wrap;
    gap: 10px;
}

.chart-card-header h2 {
    margin: 0;
    font-size: 1.5rem;
    color: #333;
    display: flex;
    align-items: center;
}

.chart-wrapper {
    position: relative;
    height: 220px;
}

.footer {
    text-align: center;
    padding: 22px;
    font-size: 1.1rem;
    color: #aaa;
}

.footer a {
    color: #1b8a94;
    text-decoration: none;
}

@media (max-width: 600px) {
    .topnav { padding: 12px 16px; }
    .content { padding: 16px 12px; }
}