:root {
    /* Light Theme */
    --background: #f4f5f7;
    --header-bg: #ffffff;
    --header-bg-glass: rgba(255, 255, 255, 0.7);
    --card-bg: rgba(255, 255, 255, 0.8);
    --text: #1c1c1e;
    --text-secondary: #6e6e73;
    --border: rgba(0, 0, 0, 0.08);
    --shadow: rgba(0, 0, 0, 0.06);
    --shadow-hover: rgba(0, 0, 0, 0.1);
    --hover: rgba(0, 0, 0, 0.05);
    --accent: #007aff;
}

.dark-theme {
    /* Dark Theme */
    --background: #0d0d0f;
    --header-bg: #1d1d1f;
    --header-bg-glass: rgba(28, 28, 30, 0.7);
    --card-bg: rgba(28, 28, 30, 0.75);
    --text: #f5f5f7;
    --text-secondary: #8e8e93;
    --border: rgba(255, 255, 255, 0.1);
    --shadow: rgba(0, 0, 0, 0.2);
    --shadow-hover: rgba(0, 0, 0, 0.3);
    --hover: rgba(255, 255, 255, 0.1);
    --accent: #0a84ff;
}

body {
    background-color: var(--background);
    color: var(--text);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    line-height: 1.6;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
    transition: background-color 0.4s ease, color 0.4s ease;
}

.main-header {
    padding: 0.75rem 1rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background: var(--header-bg-glass);
    backdrop-filter: blur(12px);
    -webkit-backdrop-filter: blur(12px);
    border-bottom: 1px solid var(--border);
    transition: background-color 0.4s ease, border-color 0.4s ease;
}

@media (min-width: 768px) {
    .main-header {
        padding: 1rem 2.5rem;
    }
}

#theme-toggle {
    transition: background-color 0.3s ease, color 0.3s ease;
}

.widget-card {
    background: var(--card-bg);
    border: 1px solid var(--border);
    box-shadow: 0 4px 12px 0 var(--shadow);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    border-radius: 1rem;
    padding: 1.25rem;
    transition: background-color 0.4s ease, border-color 0.4s ease, box-shadow 0.3s ease, transform 0.3s ease;
    display: flex;
    flex-direction: column;
}

.widget-card:hover {
    transform: translateY(-3px);
    box-shadow: 0 8px 24px 0 var(--shadow-hover);
}

.widget-title {
    font-size: 1.1rem;
    font-weight: 600;
    margin-bottom: 1rem;
    color: var(--text);
    line-height: 1.2;
}

.widget-container {
    flex-grow: 1;
    min-height: 0;
}

.widget-error {
    display: flex;
    align-items: center;
    justify-content: center;
    height: 100%;
    color: var(--text-secondary);
    font-size: 0.875rem;
    text-align: center;
    padding: 1rem;
}

.dashboard-grid {
    display: grid;
    gap: 1.25rem;
    grid-template-columns: 1fr;
}

/* Tablet Layout */
@media (min-width: 768px) {
    .dashboard-grid {
        grid-template-columns: repeat(2, 1fr);
        gap: 1.5rem;
    }
    #market-overview-widget { grid-column: 1 / 2; }
    #heatmap-widget { grid-column: 2 / 3; }
    #movers-widget { grid-column: 1 / 3; }
    #earnings-calendar-widget { grid-column: 1 / 2; }
    #economic-calendar-widget { grid-column: 2 / 3; }
    #news-feed { grid-column: 1 / 3; }
}

/* Desktop Layout */
@media (min-width: 1200px) {
    .dashboard-grid {
        grid-template-columns: repeat(3, 1fr);
        grid-auto-rows: auto;
    }
    #market-overview-widget { grid-column: 1 / 2; grid-row: 1 / 2; }
    #heatmap-widget { grid-column: 2 / 4; grid-row: 1 / 2; }
    #movers-widget { grid-column: 1 / 2; grid-row: 2 / 3; }
    #earnings-calendar-widget { grid-column: 2 / 3; grid-row: 2 / 3; }
    #economic-calendar-widget { grid-column: 3 / 4; grid-row: 2 / 3; }
    #news-feed { grid-column: 1 / 4; grid-row: 3 / 4; }
}

.light-theme .dark-icon { display: none; }
.dark-theme .light-icon { display: none; }

.light-icon, .dark-icon {
    transition: opacity 0.3s ease;
}

/* Custom Tailwind-like utilities for theme-switching */
.text-text { color: var(--text); }
.text-text-secondary { color: var(--text-secondary); }
.border-border { border-color: var(--border); }
.hover\\:bg-hover:hover { background-color: var(--hover); }
.focus\\:ring-accent:focus { ring-color: var(--accent); }