/* ==========================================================================
   1. Global Styles & Browser Resets
   ========================================================================== */

/* This enables smooth scrolling when a user clicks on a navbar link, 
   instead of instantly jumping to the section. */
html {
  scroll-behavior: smooth;
}

/* We reset the default margin on the body to 0. Browsers add a small
   margin by default, which creates unwanted white space around the page. */
body {
  margin: 0;
  /* Sets a clean, modern, and widely compatible font for the entire page. */
  font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
}

/* ==========================================================================
   2. Fixed Navigation Bar
   ========================================================================== */

.navbar {
  /* 'fixed' makes the navbar stick to the screen, even when you scroll. */
  position: fixed;
  /* 'top: 0' pins it to the very top of the browser window. */
  top: 0;
  /* Ensures the navbar spans the full width of the screen. */
  width: 100%;
  background-color: black;
  /* We use Flexbox to easily align the links inside. */
  display: flex;
  /* A high z-index ensures the navbar stays on top of all other content. */
  z-index: 1000;
}

/* This styles the individual links (<a> tags) inside the navbar. */
.navbar a {
  /* 'flex-grow: 1' tells each link to take up an equal amount of space,
     making them spread out evenly across the bar. */
  flex-grow: 1;
  color: white;
  /* Removes the default blue underline from links. */
  text-decoration: none;
  /* Adds space inside each link, making them easier to click. */
  padding: 18px 22px;
  text-align: center;
  /* Adds a smooth fade effect for the background color change on hover. */
  transition: background-color 0.3s ease;
}

/* This rule applies when you mouse over a navbar link. */
.navbar a:hover {
  background-color: #555; /* Changes the background to a dark grey. */
}

/* ==========================================================================
   3. Main Content Area
   ========================================================================== */

/* This styles the <main> tag that holds all of our sections. */
main {
  /* We add padding to the top to push all the content down,
     preventing the first section from being hidden underneath the fixed navbar. */
  padding-top: 60px; 
}

/* ==========================================================================
   4. General & Specific Section Styling
   ========================================================================== */

/* This is the base style for all <section> tags. */
section {
  /* 'min-height: 90vh' makes each section take up at least 90% of the
     browser window's height. It's more flexible than a fixed height. */
  min-height: 90vh;
  /* We use Flexbox again to perfectly center the .content div inside. */
  display: flex;
  justify-content: center; /* Horizontally centers content. */
  align-items: center;   /* Vertically centers content. */
  /* Adds space around the content inside each section. */
  padding: 40px;
  /* Ensures padding is included in the element's total height and width. */
  box-sizing: border-box;
}

/* The Intro section gets a special background image. */
#intro {
  /* The linear-gradient creates a semi-transparent black overlay,
     making the white text on top easy to read. */
  background-image: linear-gradient(rgba(0, 0, 0, 0.6), rgba(0, 0, 0, 0.6)), url('https://images.pexels.com/photos/1631677/pexels-photo-1631677.jpeg?auto=compress&cs=tinysrgb&w=1260&h=750&dpr=1');
  /* Scales the image to cover the entire section without distortion. */
  background-size: cover;
  /* Centers the image within the section. */
  background-position: center;
  /* This creates a parallax effect where the image stays still as you scroll. */
  background-attachment: fixed;
  /* Sets the text color to white for high contrast. */
  color: white;
}

/* Styles the ODD-numbered sections (1st, 3rd, 5th), but NOT the intro. */
section:nth-child(odd):not(#intro) {
  background-color: #F9FA80; /* Yellow background */
}

/* Styles the EVEN-numbered sections (2nd, 4th, 6th). */
section:nth-child(even) {
  background-color: #454545; /* Black background */
  color: #f0f0f0;            /* Light grey text */
}

/* ==========================================================================
   5. Content Layout (Image + Text)
   ========================================================================== */

/* This styles the .content div that holds the image and text. */
.content {
  display: flex;         /* Makes it a flex container for side-by-side items. */
  align-items: center;   /* Vertically aligns the image and text. */
  gap: 50px;             /* Creates a 50px space between the image and text. */
  max-width: 1200px;     /* Sets a maximum width for the content area. */
  width: 100%;
}

/* For even sections, this flips the order of items in the .content div. */
section:nth-child(even) .content {
  /* This moves the image to the right and the text to the left. */
  flex-direction: row-reverse;
}

/* We override the flex settings for the intro since it has no image. */
#intro .content {
  text-align: center;
  max-width: 800px;
}

/* ==========================================================================
   6. Text and Image Element Styling
   ========================================================================== */

.text-content {
  max-width: 600px;
}
.text-content p {
  /* Increases the space between lines of text for better readability. */
  line-height: 1.6;
}

img {
  /* Using max-width makes images responsive; they'll shrink on small screens. */
  max-width: 450px;
  /* 'height: auto' ensures the image's aspect ratio is maintained. */
  height: auto;
  border-radius: 10px; /* Adds nice rounded corners to the images. */
  /* Adds a subtle shadow for a lifting effect. */
  box-shadow: 0 4px 15px rgba(0,0,0,0.2);
}

/* ==========================================================================
   7. Responsive Design for Smaller Screens (e.g., Mobile)
   ========================================================================== */

/* This block of code only applies when the screen width is 768px or less. */
@media (max-width: 768px) {
  .content {
    /* Stacks the image and text vertically instead of side-by-side.
       The '!important' ensures this rule overrides the row-reverse rule. */
    flex-direction: column !important;
    text-align: center;
  }
}