/* ==========================================================================
   1. GLOBAL ENGINE & CUSTOM VARIABLES (Supporting Light & Dark Modes)
   ========================================================================== */
:root {
    /* Color Palette (Light Mode Default Values) */
    --primary-color: #0047AB; /* Scientific Blue */
    --accent-color: #007acc;  /* Sleek Tutoring Blue */
    --background-light: #F8F8F8;
    --background-dark: #0e1117; /* Darker background from Tutoring style */
    --text-color-dark: #111111;
    --text-color-light: #a0aec0;
    --card-bg-light: #FFFFFF;
    --card-bg-dark: rgba(255, 255, 255, 0.03); /* Translucent cards */
    --card-border: rgba(255, 255, 255, 0.1);
    --divider-color: #CCCCCC;
    --clock-bg: rgba(255, 255, 255, 0.7);

    /* Typography */
    --font-heading: 'Montserrat', sans-serif;
    --font-body: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
    --padding-base: 20px;
}

/* Base Styles (Light Mode Default) */
body {
    font-family: var(--font-body);
    color: var(--text-color-dark);
    background-color: var(--background-light);
    margin: 0;
    padding: 0;
    line-height: 1.6;
    transition: background-color 0.3s, color 0.3s;
}

/* Global Dark Mode Framework Overrides (Flipped to Lab Laser Green) */
body.dark-mode {
    color: #f0f4f8;
    background-color: var(--background-dark);
    
    /* Dynamically swap the global tokens to bright green for dark mode elements */
    --primary-color: #39FF14;
    --accent-color: #39FF14;
    --card-border: rgba(57, 255, 20, 0.2); /* Tinted card borders */
}
body.dark-mode a {
    color: var(--accent-color);
}
body.dark-mode hr {
    background-color: #262730;
}
body.dark-mode .top-left-clock {
    background-color: rgba(0, 0, 0, 0.5);
    color: #CCCCCC;
}

/* ==========================================================================
   2. REUSABLE CONTAINER MODULES (TUTORING BRAND LOOK)
   ========================================================================== */
.content-body {
    max-width: 1200px;
    margin: 0 auto;
    padding: var(--padding-base);
    position: relative;
}

.two-column-layout {
    display: flex;
    flex-direction: row;
    gap: 30px;
    margin-top: 20px;
}

.main-column {
    flex: 1;
    max-width: 800px;
    margin: 0 auto;
}

/* Tutoring-styled Unified Sections & Cards */
.card-style {
    background-color: var(--card-bg-light);
    border: 1px solid rgba(0, 0, 0, 0.08);
    padding: 25px;
    border-radius: 10px;
    margin-bottom: 30px;
    transition: background-color 0.3s, box-shadow 0.3s, border-color 0.3s;
}
body.dark-mode .card-style {
    background-color: var(--card-bg-dark);
    border: 1px solid var(--card-border);
}

/* Grid & Cards (The Tutoring Subject Cards Layout) */
.grid-container {
    display: flex;
    gap: 20px;
    margin: 25px 0;
}

.subject-card {
    flex: 1;
    background: rgba(0, 0, 0, 0.02);
    border: 1px solid rgba(0, 0, 0, 0.08);
    border-radius: 8px;
    padding: 20px;
    transition: transform 0.3s ease, border-color 0.3s, background-color 0.3s;
}
body.dark-mode .subject-card {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--card-border);
}

.subject-card:hover {
    transform: translateY(-3px);
    border-color: var(--accent-color);
}

.subject-card h3 {
    color: var(--accent-color);
    margin-top: 0;
    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
    padding-bottom: 10px;
}
body.dark-mode .subject-card h3 {
    border-bottom: 1px solid var(--card-border);
}

.subject-card ul {
    list-style: none;
    padding-left: 0;
}

.subject-card li {
    margin-bottom: 8px;
    font-size: 0.95rem;
}

/* Hero Component Headers */
.tutoring-hero {
    text-align: center;
    margin-bottom: 40px;
    padding: 20px 0;
}
.tutoring-hero h1 {
    font-size: 2.5rem;
    color: var(--accent-color);
    margin-bottom: 15px;
}

/* Headings */
h1, h2, h3 {
    font-family: var(--font-heading);
    color: var(--primary-color);
    transition: color 0.3s;
}
body.dark-mode h1, body.dark-mode h2, body.dark-mode h3 {
    color: var(--accent-color);
}

/* ==========================================================================
   3. STRUCTURAL NAVIGATION & UTILITIES
   ========================================================================== */
.main-nav {
    display: flex;
    justify-content: center;
    gap: 10px;
    padding: 15px 0;
    border-top: 1px solid var(--divider-color);
    border-bottom: 1px solid var(--divider-color);
    margin-top: 20px;
    transition: border-color 0.3s;
}
body.dark-mode .main-nav {
    border-color: #262730;
}

.main-nav a {
    padding: 8px 15px;
    border-radius: 4px;
    color: var(--text-color-dark);
    font-weight: 500;
    transition: background-color 0.3s, color 0.3s, transform 0.2s;
}
body.dark-mode .main-nav a {
    color: #EAEAEA;
}

.main-nav a:hover,
.main-nav a.active {
    background-color: var(--accent-color);
    color: white;
    transform: translateY(-2px);
    text-decoration: none;
}
/* Ensure dark mode active menu text color maintains dynamic contrast */
body.dark-mode .main-nav a:hover,
body.dark-mode .main-nav a.active {
    color: #0e1117; 
}

.main-nav a i {
    margin-right: 5px;
}

/* Mobile Nav Structure Configuration */
.mobile-nav {
    display: none;
}

/* Interactivity Elements */
.primary-btn, .theme-toggle {
    padding: 10px 20px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-weight: bold;
    background-color: var(--accent-color);
    color: white;
    transition: background-color 0.3s, opacity 0.2s;
}
.primary-btn:hover {
    opacity: 0.9;
}
body.dark-mode .primary-btn {
    color: #0e1117; /* High contrast text for dark mode button action */
}

.theme-toggle {
    position: fixed;
    bottom: 20px;
    right: 20px;
    z-index: 1001;
    background-color: var(--card-bg-light);
    border: 1px solid var(--divider-color);
    color: var(--text-color-dark);
}
body.dark-mode .theme-toggle {
    background-color: #1a1a2e;
    color: var(--accent-color);
    border: 1px solid var(--accent-color);
}

hr.thick-divider, hr {
    border: none;
    height: 2px;
    background-color: var(--divider-color);
    margin: 20px auto;
}
body.dark-mode hr.thick-divider {
    background-color: #262730;
}

footer {
    padding: 20px 0;
    border-top: 1px solid var(--divider-color);
}
body.dark-mode footer {
    border-color: #262730;
}

/* ==========================================================================
   4. MEDIA QUERIES (Phone Responsiveness Setup)
   ========================================================================== */
@media (max-width: 768px) {
    .main-nav {
        display: none;
    }
    .mobile-nav {
        display: block;
        padding: 10px 0;
    }
    .menu-toggle {
        display: block;
        width: 100%;
        padding: 10px;
        background-color: var(--accent-color);
        color: white;
        border: none;
        border-radius: 4px;
        font-size: 1.1em;
        cursor: pointer;
    }
    body.dark-mode .menu-toggle {
        color: #0e1117;
    }
    .mobile-menu-items {
        display: none;
        flex-direction: column;
        background-color: var(--card-bg-light);
        border: 1px solid var(--divider-color);
        border-top: none;
    }
    .mobile-nav.active .mobile-menu-items {
        display: flex;
    }
    .mobile-menu-items a {
        padding: 10px 15px;
        border-bottom: 1px solid #EEE;
    }
    body.dark-mode .mobile-menu-items {
        background-color: #1a1a2e;
        border-color: #444;
    }
    .two-column-layout, 
    .grid-container {
        flex-direction: column;
    }
    .subject-card {
        width: 100%;
        box-sizing: border-box;
    }
}