/* CSS Custom Properties for theming */
* {
    box-sizing: border-box;
}

body {
    margin: 0;
    padding: 0;
    background-color: var(--color-bg-secondary);
    color: var(--color-text-primary);
    transition: background-color 0.2s ease, color 0.2s ease;
}

:root {
    /* Base colors - Light mode (default) */
    --color-bg-primary: #fff;
    --color-bg-secondary: #f8f9fa;
    --color-bg-tertiary: #f3f3f3;
    --color-text-primary: #2c3e50;
    --color-text-secondary: #495057;
    --color-text-tertiary: #6c757d;
    --color-border: #dee2e6;

    /* Shadow variables */
    --shadow-sm: 0 2px 4px rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px rgb(0 0 0 / 0.1);

    /* Status colors */
    --color-status-loading: #007bff;
    --color-status-success: #28a745;
    --color-status-error: #dc3545;
    --color-status-loading-bg: #f8f9fa;
    --color-status-success-bg: #d4edda;
    --color-status-error-bg: #f8d7da;

    /* Chart colors */
    --color-chart-title: #1f2937;
    --color-chart-axis: #6b7280;
    --color-chart-grid: #e5e7eb;
    --color-accent-blue: #3b82f6;

    /* Price indicators */
    --color-price-increase: #dc3545;
    --color-price-decrease: #28a745;

    /* Spinner */
    --color-spinner-bg: #f3f3f3;
}

[data-theme="dark"] {
    /* Base colors - Dark mode */
    --color-bg-primary: #1a1a1a;
    --color-bg-secondary: #2d2d2d;
    --color-bg-tertiary: #3a3a3a;
    --color-text-primary: #e4e4e7;
    --color-text-secondary: #a1a1aa;
    --color-text-tertiary: #71717a;
    --color-border: #404040;

    /* Shadow variables - softer for dark mode */
    --shadow-sm: 0 2px 4px rgb(0 0 0 / 0.3);
    --shadow-md: 0 4px 6px rgb(0 0 0 / 0.5);

    /* Status colors - adjusted for readability */
    --color-status-loading: #3b82f6;
    --color-status-success: #22c55e;
    --color-status-error: #ef4444;
    --color-status-loading-bg: #1e3a8a;
    --color-status-success-bg: #14532d;
    --color-status-error-bg: #7f1d1d;

    /* Chart colors - lighter for visibility */
    --color-chart-title: #e4e4e7;
    --color-chart-axis: #a1a1aa;
    --color-chart-grid: #404040;
    --color-accent-blue: #60a5fa;

    /* Price indicators - more vibrant */
    --color-price-increase: #f87171;
    --color-price-decrease: #4ade80;

    /* Spinner */
    --color-spinner-bg: #3a3a3a;
}

/* Auto-detect system preference if no explicit theme set */
@media (prefers-color-scheme: dark) {
    :root:not([data-theme]) {
        /* Base colors - Dark mode */
        --color-bg-primary: #1a1a1a;
        --color-bg-secondary: #2d2d2d;
        --color-bg-tertiary: #3a3a3a;
        --color-text-primary: #e4e4e7;
        --color-text-secondary: #a1a1aa;
        --color-text-tertiary: #71717a;
        --color-border: #404040;

        /* Shadow variables */
        --shadow-sm: 0 2px 4px rgb(0 0 0 / 0.3);
        --shadow-md: 0 4px 6px rgb(0 0 0 / 0.5);

        /* Status colors */
        --color-status-loading: #3b82f6;
        --color-status-success: #22c55e;
        --color-status-error: #ef4444;
        --color-status-loading-bg: #1e3a8a;
        --color-status-success-bg: #14532d;
        --color-status-error-bg: #7f1d1d;

        /* Chart colors */
        --color-chart-title: #e4e4e7;
        --color-chart-axis: #a1a1aa;
        --color-chart-grid: #404040;
        --color-accent-blue: #60a5fa;

        /* Price indicators */
        --color-price-increase: #f87171;
        --color-price-decrease: #4ade80;

        /* Spinner */
        --color-spinner-bg: #3a3a3a;
    }
}

.app-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 20px;
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    transition: background-color 0.2s ease, color 0.2s ease, max-width 0.2s ease;
}

.app-header {
    position: relative;
    text-align: center;
    margin-bottom: 40px;
}

.app-header h1 {
    color: var(--color-text-primary);

    /* Fluid font sizing - scales from 1.5rem to 3.2rem across all viewports */
    font-size: clamp(1.5rem, 1rem + 2vw, 3.2rem);
    margin: 0;
    transition: color 0.2s ease;
}

/* Theme toggle button */
.theme-toggle {
    position: absolute;
    top: 0;
    right: 0;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 10px 15px;

    /* Fluid font sizing - scales from 1rem to 1.5rem */
    font-size: clamp(1rem, 0.8rem + 0.4vw, 1.5rem);
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
}

.theme-toggle:hover {
    background: var(--color-bg-tertiary);
    transform: scale(1.05);
}

.theme-toggle:active {
    transform: scale(0.95);
}

/* Region selector dropdown */
.region-selector {
    position: absolute;
    top: 0;
    right: 60px;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 8px 12px;

    /* Fluid font sizing across all viewport sizes */
    font-size: clamp(0.7rem, 0.4rem + 0.6vw, 1.1rem);
    cursor: pointer;
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    color: var(--color-text-primary);
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%236c757d' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 10px center;
    padding-right: 30px;

    /* Fluid max-width across all viewport sizes - scales from 90px to 240px */
    max-width: clamp(90px, 6vw + 70px, 240px);
}

.region-selector:hover {
    background-color: var(--color-bg-tertiary);
}

.region-selector:focus {
    outline: none;
    border-color: var(--color-accent-blue);
    box-shadow: 0 0 0 2px rgb(59 130 246 / 0.2);
}

[data-theme="dark"] .region-selector {
    background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' viewBox='0 0 12 12'%3E%3Cpath fill='%23a1a1aa' d='M6 8L1 3h10z'/%3E%3C/svg%3E");
}

/* Cheapest period indicator */
.cheapest-period {
    position: absolute;
    top: 0;
    left: 0;
    background: var(--color-bg-secondary);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    padding: 10px 15px;

    /* Fluid font sizing - scales from 1rem to 1.5rem */
    font-size: clamp(1rem, 0.8rem + 0.4vw, 1.5rem);
    transition: all 0.2s ease;
    box-shadow: var(--shadow-sm);
    color: var(--color-text-primary);
}

.app-main {
    display: flex;
    flex-direction: column;

    /* Fluid gap - scales from 20px to 36px */
    gap: clamp(20px, 1.5vw + 12px, 36px);
}

.app-main h2 {
    color: var(--color-text-primary);
    margin: 0 0 20px;

    /* Fluid font sizing - scales from 1.3rem to 2rem */
    font-size: clamp(1.3rem, 0.9rem + 0.6vw, 2rem);
    transition: color 0.2s ease;
}

.status-section, .chart-section, .data-section {
    background: var(--color-bg-primary);

    /* Fluid padding - scales from 18px to 32px */
    padding: clamp(18px, 1.5vw + 10px, 32px);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

/* Banner section - compact card layout */
.banner-section {
    background: var(--color-bg-primary);

    /* Fluid padding - less vertical, scales horizontally */
    padding: clamp(12px, 1vw + 8px, 20px) clamp(18px, 1.5vw + 10px, 32px);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    overflow: hidden;  /* Clip SVG to card bounds */
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.trace-banner {
    display: block;
    width: 100%;
}

.status {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px;
    border-radius: 8px;
}

.status.loading {
    background: var(--color-status-loading-bg);
    border-left: 4px solid var(--color-status-loading);
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.status.success {
    background: var(--color-status-success-bg);
    border-left: 4px solid var(--color-status-success);
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.status.error {
    background: var(--color-status-error-bg);
    border-left: 4px solid var(--color-status-error);
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.spinner {
    width: 20px;
    height: 20px;
    border: 2px solid var(--color-spinner-bg);
    border-top: 2px solid var(--color-status-loading);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}

.chart-container {
    width: 100%;
    height: 400px;
    min-height: 300px;
}

.chart-container > div {
    width: 100%;
    height: 100%;
}

.chart-placeholder, .chart-error {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 400px;
    background: var(--color-bg-secondary);
    border: 2px dashed var(--color-border);
    border-radius: 8px;
    color: var(--color-text-tertiary);
    transition: background-color 0.2s ease, border-color 0.2s ease, color 0.2s ease;
}

/* Wrapper for day cards (vertical stacking) */
.data-summary {
    display: flex;
    flex-direction: column;

    /* Fluid gap - scales from 15px to 24px */
    gap: clamp(15px, 1vw + 10px, 24px);
}

/* Individual day card */
.day-summary-card {
    background: var(--color-bg-primary);
    padding: 20px;
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.day-summary-card h2 {
    margin: 0 0 15px;
    color: var(--color-text-primary);
    font-size: 1.2rem;
    transition: color 0.2s ease;
}

/* Tomorrow card visual distinction */
.day-summary-card.tomorrow {
    border-left: 4px solid var(--color-accent-blue);
    transition: border-color 0.2s ease;
}

.summary-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));

    /* Fluid gap - scales from 15px to 24px */
    gap: clamp(15px, 1vw + 10px, 24px);
}

.summary-item {
    text-align: center;
    padding: 20px;
    background: var(--color-bg-secondary);
    border-radius: 8px;
    transition: background-color 0.2s ease;
}

.summary-item h3 {
    margin: 0 0 10px;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.2s ease;
}

.summary-value {
    margin: 0;

    /* Fluid font sizing - scales from 1.2rem to 1.8rem */
    font-size: clamp(1.2rem, 0.9rem + 0.5vw, 1.8rem);
    font-weight: bold;
    color: var(--color-text-primary);
    transition: color 0.2s ease;
}

.tracker-section {
    background: var(--color-bg-primary);

    /* Fluid padding - scales from 18px to 32px */
    padding: clamp(18px, 1.5vw + 10px, 32px);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.tracker-display {
    margin-top: 10px;
}

.tracker-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));

    /* Fluid gap - scales from 15px to 24px */
    gap: clamp(15px, 1vw + 10px, 24px);
}

.tracker-item {
    text-align: center;
    padding: 20px;
    background: var(--color-bg-secondary);
    border-radius: 8px;
    transition: background-color 0.2s ease;
}

.tracker-item h3 {
    margin: 0 0 10px;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.2s ease;
}

.tracker-value {
    margin: 0;

    /* Fluid font sizing - scales from 1.2rem to 1.8rem */
    font-size: clamp(1.2rem, 0.9rem + 0.5vw, 1.8rem);
    font-weight: bold;
    color: var(--color-text-primary);
    transition: color 0.2s ease;
}

.tracker-item-tomorrow {
    text-align: center;
    padding: 20px;
    background: var(--color-bg-secondary);
    border-radius: 8px;
    border-left: 4px solid var(--color-status-loading);
    transition: background-color 0.2s ease, border-color 0.2s ease;
}

.tracker-item-tomorrow h3 {
    margin: 0 0 10px;
    color: var(--color-text-secondary);
    font-size: 0.9rem;
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.2s ease;
}

.tracker-value-tomorrow {
    margin: 0;

    /* Fluid font sizing - scales from 1.2rem to 1.8rem */
    font-size: clamp(1.2rem, 0.9rem + 0.5vw, 1.8rem);
    font-weight: bold;
    color: var(--color-text-primary);
    transition: color 0.2s ease;
}

.price-increase {
    color: var(--color-price-increase);
    font-size: 1.1rem;
    transition: color 0.2s ease;
}

.price-decrease {
    color: var(--color-price-decrease);
    font-size: 1.1rem;
    transition: color 0.2s ease;
}

/* Carbon Intensity Section */
.carbon-section {
    background: var(--color-bg-primary);

    /* Fluid padding - scales from 16px to 28px */
    padding: clamp(16px, 1.3vw + 8px, 28px);
    border-radius: 12px;
    box-shadow: var(--shadow-md);
    transition: background-color 0.2s ease, box-shadow 0.2s ease;
}

.carbon-display {
    margin-top: 5px;
}

.carbon-grid {
    display: grid;
    grid-template-columns: 1fr 1fr 1fr;

    /* Fluid gap - scales from 12px to 20px */
    gap: clamp(12px, 0.8vw + 8px, 20px);
}

.carbon-item {
    text-align: center;
    padding: 15px;
    background: var(--color-bg-secondary);
    border-radius: 8px;
    transition: background-color 0.2s ease;
}

.carbon-item h3 {
    margin: 0 0 8px;
    color: var(--color-text-secondary);
    font-size: 0.85rem; /* Slightly smaller */
    text-transform: uppercase;
    letter-spacing: 1px;
    transition: color 0.2s ease;
}

.carbon-value {
    margin: 0 0 3px;
    font-size: 1.6rem;
    font-weight: bold;
    color: var(--color-text-primary);
    transition: color 0.2s ease;
}

.carbon-value-small {
    margin: 8px 0 0;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--color-text-primary);
    transition: color 0.2s ease;
}

.carbon-unit {
    font-size: 0.85rem;
    font-weight: normal;
    color: var(--color-text-secondary);
}

.carbon-source {
    margin: 3px 0 0;
    font-size: 0.75rem;
    color: var(--color-text-tertiary);
    font-style: italic;
    transition: color 0.2s ease;
}

.carbon-time {
    margin: 8px 0 0;
    font-size: 0.75rem;
    color: var(--color-text-tertiary);
    transition: color 0.2s ease;
}

.carbon-item-current {
    grid-column: 1;
}

.carbon-item-current .carbon-value {
    font-size: 2.2rem;
}

.carbon-item-next {
    grid-column: 2;
}

.carbon-item-next .carbon-value {
    font-size: 2.2rem;
}

.carbon-item-change {
    grid-column: 3;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.carbon-change {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.4rem;
    font-size: 1.4rem;
    font-weight: 600;
    padding: 10px 0;
}

.carbon-change-icon {
    font-size: 2.2rem;
    line-height: 1;
}

.carbon-change-value {
    font-size: 0.95rem;
    line-height: 1.2;
}

.carbon-change-increasing {
    color: #dc2626;
}

.carbon-change-decreasing {
    color: #059669;
}

.carbon-change-stable {
    color: #6b7280;
}

/* Carbon Index Badge */
.carbon-index-badge {
    display: inline-block;
    padding: 12px 24px;
    border-radius: 8px;
    font-size: 1rem;
    font-weight: bold;
    color: white;
    margin: 10px 0;
    text-transform: uppercase;
    letter-spacing: 1px;
    box-shadow: 0 2px 4px rgb(0 0 0 / 0.15);
    transition: transform 0.2s ease;
}

.carbon-index-badge:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgb(0 0 0 / 0.2);
}

/* Carbon intensity level colors */
.intensity-very-low {
    background: linear-gradient(135deg, #059669 0%, #10b981 100%);
}

.intensity-low {
    background: linear-gradient(135deg, #10b981 0%, #34d399 100%);
}

.intensity-moderate {
    background: linear-gradient(135deg, #f59e0b 0%, #fbbf24 100%);
}

.intensity-high {
    background: linear-gradient(135deg, #f97316 0%, #fb923c 100%);
}

.intensity-very-high {
    background: linear-gradient(135deg, #dc2626 0%, #ef4444 100%);
}

/* Dark mode adjustments for carbon section */
[data-theme="dark"] .carbon-index-badge {
    box-shadow: 0 2px 4px rgb(0 0 0 / 0.4);
}

[data-theme="dark"] .carbon-index-badge:hover {
    box-shadow: 0 4px 8px rgb(0 0 0 / 0.6);
}

[data-theme="dark"] .carbon-change-increasing {
    color: #f87171;
}

[data-theme="dark"] .carbon-change-decreasing {
    color: #10b981;
}

[data-theme="dark"] .carbon-change-stable {
    color: #9ca3af;
}

/* Large desktop (>= 1400px) - Scale container and elements */
@media (width >= 1400px) {
    .app-container {
        max-width: 1400px;
        padding: 24px;
    }

    .app-header h1 {
        font-size: 2.7rem;
    }

    .region-selector {
        font-size: clamp(0.85rem, 0.5rem + 0.5vw, 1rem);
        max-width: clamp(140px, 10vw + 50px, 200px);
        padding: 9px 14px;
        padding-right: 32px;
    }

    .cheapest-period {
        font-size: 1.3rem;
        padding: 11px 16px;
    }

    .theme-toggle {
        font-size: 1.3rem;
        padding: 11px 16px;
    }
}

/* Extra large desktop (>= 1600px) - Continue scaling */
@media (width >= 1600px) {
    .app-container {
        max-width: 1600px;
        padding: 28px;
    }

    .app-header h1 {
        font-size: 3rem;
    }

    .region-selector {
        font-size: clamp(0.9rem, 0.5rem + 0.5vw, 1.1rem);
        max-width: clamp(160px, 11vw + 50px, 220px);
        padding: 10px 16px;
        padding-right: 34px;
    }

    .cheapest-period {
        font-size: 1.4rem;
        padding: 12px 18px;
    }

    .theme-toggle {
        font-size: 1.4rem;
        padding: 12px 18px;
    }
}

/* Ultra wide (>= 1920px) - Maximum comfortable reading width */
@media (width >= 1920px) {
    .app-container {
        max-width: 90%; /* Cap at 90% for ultra-wide monitors */
        padding: 32px;
    }

    .app-header h1 {
        font-size: 3.2rem;
    }

    .region-selector {
        font-size: 1.1rem;
        max-width: 240px;
        padding: 12px 18px;
        padding-right: 36px;
    }

    .cheapest-period {
        font-size: 1.5rem;
        padding: 14px 20px;
    }

    .theme-toggle {
        font-size: 1.5rem;
        padding: 14px 20px;
    }
}

/* Large tablet / small desktop (< 1100px) */
@media (width <= 1100px) {
    .app-header {
        min-height: 90px;
    }

    .app-header h1 {
        font-size: 1.7rem;
        padding-top: 50px;
        padding-left: 140px;
        padding-right: 140px;
    }

    .region-selector {
        top: 0;
        right: 50px;
        max-width: clamp(95px, 8vw + 35px, 120px);
        padding: 6px 8px;
        padding-right: 24px;
    }

    .cheapest-period {
        top: 0; /* Same row as other controls */
        left: 0;
        font-size: 0.9rem;
        padding: 6px 10px;
        max-width: 120px; /* Limit width */
    }

    .theme-toggle {
        top: 0;
        right: 0;
    }
}

/* Tablet and below (< 768px) - 2-3 column layouts with optimized spacing */
@media (width <= 768px) {
    .app-container {
        padding: 12px;
    }

    .app-header {
        margin-bottom: 30px;
        min-height: 70px;
    }

    .app-header h1 {
        font-size: 1.4rem;
        padding-top: 42px;
        padding-left: 5px;
        padding-right: 5px;
    }

    .region-selector {
        top: 0;
        right: 50px;

        /* Fluid sizing continues, with tighter constraints */
        max-width: clamp(85px, 10vw + 20px, 105px);
        padding: 6px 8px;
        padding-right: 24px;
    }

    .theme-toggle {
        padding: 8px 12px;
        font-size: 1rem;
    }

    .cheapest-period {
        top: 0; /* Keep in top row */
        left: 0;
        font-size: 0.85rem;
        padding: 6px 10px;
        max-width: 110px;
        white-space: nowrap;
        overflow: hidden;
        text-overflow: ellipsis;
    }

    /* Sections with reduced padding */
    .status-section, .chart-section, .data-section,
    .banner-section, .tracker-section, .carbon-section {
        padding: 18px;
    }

    .day-summary-card {
        padding: 16px;
    }

    /* 2 columns for most grids */
    .summary-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }

    .tracker-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 15px;
    }

    .carbon-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 12px; /* Tighter for compact design */
    }

    /* Carbon items span adjustments */
    .carbon-item-current,
    .carbon-item-next {
        grid-column: span 1;
    }

    .carbon-item-change {
        grid-column: span 2;
    }

    .carbon-item-current .carbon-value,
    .carbon-item-next .carbon-value {
        font-size: 1.8rem;
    }

    .carbon-value {
        font-size: 1.4rem;
    }

    /* Reduce item padding */
    .summary-item,
    .tracker-item,
    .tracker-item-tomorrow,
    .carbon-item {
        padding: 15px;
    }

    .carbon-item {
        padding: 12px; /* Extra compact for carbon */
    }
}

/* Small tablet / large mobile (< 600px) - Maintain 2 columns, tighter spacing */
@media (width <= 600px) {
    .app-container {
        padding: 10px;
    }

    .app-header {
        min-height: 60px;
    }

    .app-header h1 {
        font-size: 1.2rem; /* Smaller to reduce vertical space */
        padding-top: 38px; /* Adjusted for smaller controls */
    }

    .region-selector {
        right: 45px;
        font-size: 0.7rem;
        padding: 5px 6px;
        padding-right: 22px;
        max-width: 90px;
    }

    .cheapest-period {
        font-size: 0.8rem;
        padding: 5px 8px;
        max-width: 100px;
    }

    .theme-toggle {
        padding: 6px 10px;
        font-size: 0.9rem;
    }

    /* Further reduce section padding */
    .status-section, .chart-section, .data-section,
    .banner-section, .tracker-section, .carbon-section {
        padding: 15px;
    }

    .day-summary-card {
        padding: 14px;
    }

    /* Keep 2 columns but tighter gaps */
    .summary-grid {
        gap: 12px;
    }

    .tracker-grid {
        gap: 12px;
    }

    .carbon-grid {
        gap: 12px;
    }

    /* Compact item padding */
    .summary-item,
    .tracker-item,
    .tracker-item-tomorrow,
    .carbon-item {
        padding: 12px;
    }

    .carbon-item {
        padding: 10px; /* Extra compact */
    }

    /* Slightly smaller fonts */
    .summary-value,
    .tracker-value,
    .tracker-value-tomorrow {
        font-size: 1.3rem;
    }

    .carbon-item-current .carbon-value,
    .carbon-item-next .carbon-value {
        font-size: 1.6rem;
    }

    .carbon-value {
        font-size: 1.3rem;
    }

    .carbon-value-small {
        font-size: 1rem;
    }

    .carbon-change {
        font-size: 1.2rem;
        padding: 8px 0;
    }

    .carbon-change-icon {
        font-size: 1.8rem;
    }
}

/* Mobile (< 480px) - 2 columns, maximum space utilization */
@media (width <= 480px) {
    .app-container {
        padding: 8px;
    }

    .app-header {
        min-height: 55px;
    }

    .app-header h1 {
        font-size: 1.1rem; /* Smaller title for mobile */
        padding-top: 35px; /* Less padding to reduce clash */
    }

    .region-selector {
        max-width: 80px;
        font-size: 0.65rem;
        right: 42px;
        padding: 4px 5px;
        padding-right: 20px;
    }

    .theme-toggle {
        padding: 5px 8px;
        font-size: 0.85rem;
    }

    .cheapest-period {
        font-size: 0.7rem;
        padding: 4px 7px;
        max-width: 90px;
    }

    /* Minimal section padding */
    .status-section, .chart-section, .data-section,
    .banner-section, .tracker-section, .carbon-section {
        padding: 12px;
    }

    .day-summary-card {
        padding: 12px;
    }

    .day-summary-card h2 {
        font-size: 1.1rem;
    }

    /* Maintain 2 columns with minimal gaps */
    .summary-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .tracker-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    .carbon-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 10px;
    }

    /* Minimal item padding */
    .summary-item,
    .tracker-item,
    .tracker-item-tomorrow,
    .carbon-item {
        padding: 10px;
    }

    .carbon-item {
        padding: 8px; /* Extra minimal for carbon */
    }

    /* Compact fonts */
    .summary-item h3,
    .tracker-item h3,
    .tracker-item-tomorrow h3,
    .carbon-item h3 {
        font-size: 0.75rem;
        margin-bottom: 6px;
    }

    .summary-value,
    .tracker-value,
    .tracker-value-tomorrow {
        font-size: 1.2rem;
    }

    .carbon-item-current .carbon-value,
    .carbon-item-next .carbon-value {
        font-size: 1.4rem;
    }

    .carbon-value {
        font-size: 1.2rem;
    }

    .carbon-value-small {
        font-size: 0.95rem;
    }

    .carbon-change {
        font-size: 1.1rem;
        padding: 6px 0;
    }

    .carbon-change-icon {
        font-size: 1.6rem;
    }

    .carbon-change-value {
        font-size: 0.85rem;
    }

    .carbon-index-badge {
        font-size: 0.9rem;
        padding: 8px 16px;
    }

    .price-increase,
    .price-decrease {
        font-size: 1rem;
    }
}

/* ============================================
   Accessibility - Screen Reader Only
   ============================================ */

/* Screen reader only - visually hidden but accessible */
.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border-width: 0;
}

.sr-only:focus {
    position: static;
    width: auto;
    height: auto;
    padding: inherit;
    margin: inherit;
    overflow: visible;
    clip: auto;
    white-space: normal;
}