/* --- Global Resets & Base Styles --- */
*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

html {
    scroll-behavior: smooth; /* Smooth scrolling for potential future navigation */
    font-size: 100%; /* Base font size (usually 16px) */
}

body {
    font-family: 'Nunito Sans', sans-serif; /* Clean sans-serif font */
    line-height: 1.6;
    color: #333; /* Dark grey for readability */
    background-color: #f8f9fa; /* Light grey background */
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

/* --- Container --- */
.container {
    max-width: 960px; /* Max width for content */
    margin-left: auto;
    margin-right: auto;
    padding-left: 20px;
    padding-right: 20px;
}

/* --- Typography --- */
h1, h2 {
    font-family: 'Roboto', sans-serif; /* Slightly different font for headings */
    font-weight: 500; /* Medium weight for headings */
    color: #2c3e50; /* Dark blue/grey heading color */
    margin-bottom: 0.75em;
    line-height: 1.3;
}

h1 {
    font-size: 2.5rem; /* Responsive font size (adjust as needed) */
    text-align: center;
}

h2 {
    font-size: 1.8rem;
    border-bottom: 2px solid #e0e0e0; /* Subtle separator */
    padding-bottom: 0.3em;
    margin-bottom: 1em;
}

p {
    margin-bottom: 1em;
    color: #555; /* Slightly lighter text color */
}

a {
    color: #3498db; /* Professional blue link color */
    text-decoration: none;
    transition: color 0.2s ease-in-out, text-decoration 0.2s ease-in-out;
}

a:hover,
a:focus {
    color: #2980b9; /* Darker blue on hover */
    text-decoration: underline;
}

ul {
    list-style: none; /* Remove default bullets */
    padding-left: 0;
}

li {
    margin-bottom: 0.8em;
}

strong {
    font-weight: 700; /* Use bold weight from Nunito Sans */
    color: #34495e; /* Slightly darker for emphasis */
}

/* --- Header --- */
.site-header {
    background-color: #34495e; /* Dark slate blue header */
    color: #ecf0f1; /* Light text color for header */
    padding: 3rem 0;
    text-align: center;
    margin-bottom: 2rem;
}

.site-header h1 {
    color: #ffffff; /* White heading in header */
    margin-bottom: 0.25em;
}

.site-header .subtitle {
    font-size: 1.1rem;
    color: #bdc3c7; /* Lighter grey subtitle */
    margin-bottom: 0;
    font-weight: 400;
}

/* --- Content Sections --- */
.content-section {
    padding: 2.5rem 0; /* Vertical spacing between sections */
}

.content-section.alt-bg {
    background-color: #ffffff; /* White background for alternate sections */
    border-top: 1px solid #e7e7e7;
    border-bottom: 1px solid #e7e7e7;
}

/* --- Feature List --- */
.feature-list li {
    padding-left: 1.5em; /* Indent list items */
    position: relative;
}

.feature-list li::before {
    content: '\2022';
        /* Checkmark symbol */
    position: absolute;
    left: 0;
    top: 1px; /* Adjust vertical alignment */
    color: #000000;
        /* Black dot */
    font-weight: bold;
}

/* --- Video Links --- */
.video-links {
    margin-top: 1.5rem;
}

.video-link {
    display: inline-block; /* Layout links */
    margin-right: 1rem;
    margin-bottom: 0.5rem; /* Spacing for wrapping */
    padding: 0.5rem 1rem;
    border: 1px solid #3498db;
    border-radius: 4px;
    background-color: #ffffff;
    transition: background-color 0.2s ease-in-out, color 0.2s ease-in-out;
}

.video-link:hover,
.video-link:focus {
    background-color: #3498db;
    color: #ffffff;
    text-decoration: none;
}

/* --- Footer --- */
.site-footer {
    background-color: #2c3e50; /* Dark footer background */
    color: #bdc3c7; /* Light grey footer text */
    text-align: center;
    padding: 1.5rem 0;
    margin-top: 2rem;
    font-size: 0.9rem;
}

.site-footer p {
    margin-bottom: 0.25em;
    color: #bdc3c7;
}

.site-footer a {
    color: #ecf0f1; /* Lighter link color for footer */
}

.site-footer a:hover,
.site-footer a:focus {
    color: #ffffff;
}

/* --- Basic Responsiveness --- */
@media (max-width: 768px) {
    h1 {
        font-size: 2rem;
    }
    h2 {
        font-size: 1.6rem;
    }
    .site-header {
        padding: 2rem 0;
    }
    .content-section {
        padding: 2rem 0;
    }
}

@media (max-width: 480px) {
    h1 {
        font-size: 1.8rem;
    }
    h2 {
        font-size: 1.4rem;
    }
    body {
        font-size: 0.95rem;
    }
    .container {
        padding-left: 15px;
        padding-right: 15px;
    }
    .video-link {
        display: block; /* Stack links vertically on small screens */
        margin-right: 0;
        margin-bottom: 0.75rem;
        text-align: center;
    }
}