/* Base Styles and CSS Reset */
* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    touch-action: manipulation;
}

:root {
    /* Color Variables */
    --primary-color: #2c3e50;
    --secondary-color: #3498db;
    --accent-color: #e74c3c;
    
    /* Dark Theme Colors */
    --dark-bg: #121212;
    --dark-card-bg: #1e1e1e;
    --dark-text: #f4f4f4;
    --dark-border: #333;
    --dark-shadow: rgba(0, 0, 0, 0.3);
    --dark-overlay: rgba(0, 0, 0, 0.9);
    
    /* Light Theme Colors */
    --light-bg: #f4f4f4;
    --light-card-bg: #ffffff;
    --light-text: #333;
    --light-border: #ddd;
    --light-shadow: rgba(0, 0, 0, 0.1);
    --light-overlay: rgba(240, 240, 240, 0.95);
    
    /* Active Theme Colors (defaults to dark) */
    --bg-color: var(--dark-bg);
    --card-bg: var(--dark-card-bg);
    --text-color: var(--dark-text);
    --border-color: var(--dark-border);
    --shadow-color: var(--dark-shadow);
    --overlay-bg: var(--dark-overlay);
    
    /* Other Variables */
    --button-hover: rgba(255, 255, 255, 0.3);
    --animation-speed: 3s;
    --border-radius: 8px;
    --transition-speed: 0.3s;
}

/* Light Theme Variables */
body.light-theme {
    --bg-color: var(--light-bg);
    --card-bg: var(--light-card-bg);
    --text-color: var(--light-text);
    --border-color: var(--light-border);
    --shadow-color: var(--light-shadow);
    --overlay-bg: var(--light-overlay);
    --primary-color: #3f51b5;
    --secondary-color: #2196f3;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Arial, sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.6;
    transition: background-color var(--transition-speed) ease, color var(--transition-speed) ease;
}

/* Navigation Bar Styles */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: var(--primary-color);
    color: var(--dark-text); /* Always light text on dark navbar */
    padding: 15px 20px;
    box-shadow: 0 2px 10px var(--shadow-color);
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    z-index: 1000;
    flex-wrap: wrap;
    transition: background-color var(--transition-speed) ease;
}

.navbar > div:first-child {
    font-size: 1.2rem;
    font-weight: bold;
}

.nav-controls {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.nav-controls button {
    background-color: rgba(255, 255, 255, 0.2);
    color: white;
    border: none;
    padding: 8px 15px;
    border-radius: 5px;
    cursor: pointer;
    transition: background-color var(--transition-speed), transform 0.2s;
    font-size: 0.9rem;
}

.nav-controls button:hover {
    background-color: var(--button-hover);
    transform: translateY(-2px);
}

.nav-controls button.active {
    background-color: var(--secondary-color);
}

/* Focus Styles for Keyboard Navigation */
button:focus,
input:focus,
select:focus {
    outline: 2px solid var(--secondary-color);
    outline-offset: 2px;
}

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