/* === CSS VARIABLES FROM YOUR COLOUR PALETTE === */
    /* 	Defines your colour palette as reusable variables */
:root {
  --oxford-blue: #1c2636;
  --prussian-blue: #1c2e48;
  --indigo-dye: #29446a;
  --lapis-lazuli: #4e6586;
  --glaucous: #5b7295;
  --glaucous-2: #6780a5;
  --silver-lake-blue: #748eb4;
  --vista-blue: #809bc4;
  --vista-blue-2: #8da9d3;

  --font-main: 'Segoe UI', sans-serif;
}

/* === RESET & BASICS === */
    /* Resets styles and sets defaults */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

body {
  font-family: var(--font-main);
  color: var(--oxford-blue);
  background-color: white;
  line-height: 1.6;
  padding: 0;
  margin: 0;
}

/* === HEADER & NAVIGATION === */
    /* Styles your logo and navigation bar */
header {
  background-color: var(--prussian-blue);
  color: white;
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 1rem 2rem;
  flex-wrap: wrap;
}

.logo {
  height: 60px;
  /* filter: brightness(200%); or use: invert(1) if it’s on white */
  filter: invert(1); /*invert(1) is shorthand for invert(100%) — either works*/
}

nav ul {
  display: flex;
  gap: 1.5rem;
  list-style: none;
}

nav a {
  color: white;
  text-decoration: none;
  font-weight: bold;
}

nav a:hover {
  color: var(--vista-blue-2);
}

/* === MAIN SECTIONS === */
    /* Adds spacing and colours to content sections */
main section {
  padding: 4rem 2rem;
  max-width: 900px;
  margin: auto;
}

section#hero {
  background-color: var(--silver-lake-blue);
  color: white;
  text-align: center;
}

section#certifications ul {
  margin-top: 1rem;
  padding-left: 1.2rem;
}

/* === FOOTER === */
    /* Adds a styled footer */
footer {
  text-align: center;
  padding: 1rem;
  background-color: var(--prussian-blue);
  color: white;
  font-size: 0.9rem;
}

/* === RESPONSIVE === */
    /* Makes the layout responsive on small screens */
@media (max-width: 600px) {
  nav ul {
    flex-direction: column;
    align-items: flex-start;
    gap: 0.5rem;
  }

  header {
    flex-direction: column;
    align-items: flex-start;
  }

  .logo {
    margin-bottom: 1rem;
  }
}