:root {
    --bg-color: #f4f7f6;
    --card-bg: #ffffff;
    --text-main: #2c3e50;
    --text-muted: #7f8c8d;
    --primary: #3498db;
    --primary-hover: #2980b9;
    
    --status-grey: #bdc3c7;
    --status-green: #2ecc71;
    --status-yellow: #f1c40f;
    --status-red: #e74c3c;
    
    --shadow-sm: 0 4px 6px rgba(0,0,0,0.05);
    --shadow-md: 0 10px 20px rgba(0,0,0,0.08);
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

body {
    font-family: 'Inter', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-main);
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: 100vh;
}

.container {
    width: 100%;
    max-width: 1000px;
    padding: 2rem;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
    padding-bottom: 1rem;
    border-bottom: 2px solid rgba(0,0,0,0.05);
}

.logo {
    display: flex;
    align-items: center;
    gap: 10px;
}

.logo-icon {
    font-size: 2rem;
}

h1 {
    font-size: 1.8rem;
    font-weight: 700;
    color: var(--text-main);
    letter-spacing: -0.5px;
}

.connect-btn {
    background-color: var(--primary);
    color: white;
    border: none;
    padding: 10px 24px;
    font-size: 1rem;
    font-weight: 600;
    border-radius: 8px;
    cursor: pointer;
    transition: background-color 0.3s ease, transform 0.1s ease;
    box-shadow: var(--shadow-sm);
}

.connect-btn:hover {
    background-color: var(--primary-hover);
}

.connect-btn:active {
    transform: scale(0.98);
}

.connect-btn.connected {
    background-color: var(--status-red);
}

.status-banner {
    background-color: var(--card-bg);
    border-radius: 12px;
    padding: 1.5rem;
    margin-bottom: 2rem;
    display: flex;
    align-items: center;
    gap: 15px;
    box-shadow: var(--shadow-md);
    transition: all 0.3s ease;
    border-left: 8px solid var(--status-grey);
}

.status-indicator {
    width: 20px;
    height: 20px;
    border-radius: 50%;
    background-color: var(--status-grey);
    box-shadow: 0 0 10px rgba(0,0,0,0.1);
    transition: all 0.3s ease;
}

.status-indicator.green {
    background-color: var(--status-green);
    box-shadow: 0 0 15px var(--status-green);
}

.status-indicator.yellow {
    background-color: var(--status-yellow);
    box-shadow: 0 0 15px var(--status-yellow);
}

.status-indicator.red {
    background-color: var(--status-red);
    box-shadow: 0 0 20px var(--status-red);
    animation: blink 1s infinite alternate;
}

@keyframes blink {
    0% { opacity: 1; }
    100% { opacity: 0.5; }
}

h2 {
    font-weight: 600;
    font-size: 1.4rem;
}

.sensors-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.5rem;
}

.sensor-card {
    background-color: var(--card-bg);
    border-radius: 16px;
    padding: 2rem;
    display: flex;
    align-items: flex-start;
    gap: 20px;
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s ease, box-shadow 0.3s ease;
    border: 2px solid transparent;
}

.sensor-card:hover {
    transform: translateY(-5px);
    box-shadow: var(--shadow-md);
}

.sensor-icon {
    font-size: 2.5rem;
    background-color: var(--bg-color);
    width: 60px;
    height: 60px;
    display: flex;
    justify-content: center;
    align-items: center;
    border-radius: 12px;
}

.sensor-info {
    flex: 1;
}

.sensor-info h3 {
    font-size: 1.1rem;
    color: var(--text-muted);
    font-weight: 600;
    margin-bottom: 8px;
}

.value-container {
    display: flex;
    align-items: baseline;
    gap: 5px;
    margin-bottom: 8px;
}

.value {
    font-size: 2.5rem;
    font-weight: 700;
    color: var(--text-main);
}

.unit {
    font-size: 1.2rem;
    font-weight: 600;
    color: var(--text-muted);
}

.sensor-status {
    font-size: 0.9rem;
    font-weight: 600;
    color: var(--status-grey);
}

/* Dynamic Classes */
.card-green {
    border-color: rgba(46, 204, 113, 0.3);
}
.card-green .sensor-status { color: var(--status-green); }

.card-yellow {
    border-color: rgba(241, 196, 15, 0.5);
    background-color: rgba(241, 196, 15, 0.02);
}
.card-yellow .sensor-status { color: #d4ac0d; }

.card-red {
    border-color: rgba(231, 76, 60, 0.5);
    background-color: rgba(231, 76, 60, 0.05);
    animation: danger-pulse 1.5s infinite;
}
.card-red .sensor-status { color: var(--status-red); }

@keyframes danger-pulse {
    0% { box-shadow: 0 0 0 0 rgba(231, 76, 60, 0.4); }
    70% { box-shadow: 0 0 0 15px rgba(231, 76, 60, 0); }
    100% { box-shadow: 0 0 0 0 rgba(231, 76, 60, 0); }
}