:root {
    --bg-color: #0f172a;
    --card-bg: rgba(30, 41, 59, 0.7);
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --accent-color: #38bdf8;
    --success-color: #4ade80;
    --warning-color: #facc15;
    --danger-color: #f87171;
    --font-family: 'Inter', sans-serif;
    --chart-grid: rgba(255, 255, 255, 0.1);
    --chart-text: #94a3b8;
}

[data-theme="light"] {
    --bg-color: #ffffff;
    --card-bg: #f1f5f9;
    --text-primary: #0f172a;
    --text-secondary: #475569;
    --accent-color: #0284c7;
    --chart-grid: rgba(0, 0, 0, 0.1);
    --chart-text: #475569;
}

#theme-toggle {
    background: none;
    border: 1px solid var(--text-secondary);
    color: var(--text-primary);
    padding: 0.5rem;
    border-radius: 0.5rem;
    cursor: pointer;
    font-size: 1.2rem;
    transition: all 0.2s;
}

#theme-toggle:hover {
    background: rgba(255, 255, 255, 0.1);
}

[data-theme="light"] #theme-toggle:hover {
    background: rgba(0, 0, 0, 0.05);
}

body {
    margin: 0;
    padding: 0;
    font-family: var(--font-family);
    background-color: var(--bg-color);
    color: var(--text-primary);
    min-height: 100vh;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 2rem;
}

header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 2rem;
}

h1 {
    font-weight: 600;
    margin: 0;
}

.header-info {
    display: flex;
    align-items: center;
    gap: 1rem;
}

.status-online {
    color: var(--success-color);
    font-size: 0.9rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.status-online::before {
    content: '';
    display: block;
    width: 8px;
    height: 8px;
    background-color: var(--success-color);
    border-radius: 50%;
    box-shadow: 0 0 8px var(--success-color);
}

.header-time {
    color: var(--text-secondary);
    font-size: 0.9rem;
}

.cards-container {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin-bottom: 3rem;
}

.card {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1rem;
    padding: 1.5rem;
    transition: transform 0.2s;
}

.card:hover {
    transform: translateY(-5px);
}

.card h3 {
    margin-top: 0;
    color: var(--text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Row layout for temperature + humidity */
.metrics-row {
    display: flex;
    gap: 2rem;
    justify-content: center;
    align-items: baseline;
    margin-bottom: 1rem;
}

.metric-item {
    display: flex;
    align-items: baseline;
    gap: 0.3rem;
}

.value {
    font-size: 2.5rem;
    font-weight: 600;
}

.unit {
    font-size: 1rem;
    color: var(--text-secondary);
}

/* Battery indicator - larger */
.battery-large {
    display: flex;
    justify-content: center;
    align-items: center;
    font-size: 1.5rem;
    font-weight: 600;
    margin: 1rem 0 0.5rem 0;
}

/* Combo sensor: 2-column temperature layout */
.combo-temps {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 1.5rem;
    margin-bottom: 1rem;
}

.temp-col {
    display: flex;
    flex-direction: column;
    align-items: center;
}

.temp-label {
    font-size: 0.7rem;
    color: var(--text-secondary);
    text-transform: uppercase;
    margin-bottom: 0.3rem;
}

/* Shared metrics (humidity + battery for combo) */
.shared-metrics {
    display: flex;
    gap: 2rem;
    justify-content: center;
    align-items: center;
}

.charts-container {
    background: var(--card-bg);
    backdrop-filter: blur(10px);
    border: 1px solid rgba(255, 255, 255, 0.1);
    border-radius: 1rem;
    padding: 1.5rem;
}

.chart-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1.5rem;
    flex-wrap: wrap;
    gap: 1rem;
}

.chart-header h2 {
    margin: 0;
    font-size: 1.2rem;
    font-weight: 600;
}

.filters {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

input[type="datetime-local"] {
    background: rgba(255, 255, 255, 0.1);
    border: 1px solid rgba(255, 255, 255, 0.2);
    border-radius: 0.5rem;
    padding: 0.5rem;
    color: var(--text-primary);
    font-family: var(--font-family);
    color-scheme: dark;
}

[data-theme="light"] input[type="datetime-local"] {
    background: #ffffff;
    border: 1px solid var(--text-secondary);
    color: var(--text-primary);
    color-scheme: light;
}

.btn-primary {
    background-color: var(--accent-color);
    color: var(--bg-color);
    border: none;
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: opacity 0.2s;
}

.btn-primary:hover {
    opacity: 0.9;
}

.btn-secondary {
    background-color: transparent;
    color: var(--text-primary);
    border: 1px solid var(--text-secondary);
    padding: 0.5rem 1rem;
    border-radius: 0.5rem;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.btn-secondary:hover {
    background-color: rgba(255, 255, 255, 0.1);
    border-color: var(--text-primary);
}

[data-theme="light"] .btn-secondary:hover {
    background-color: rgba(0, 0, 0, 0.05);
}

.chart-wrapper {
    position: relative;
    height: 400px;
    width: 100%;
}