style with responsive styling

style.css

/*
Colours used:
Primary Colour (pink): #FFECE8;
Secondary Colour (brown): #BF491F; #FFA282; #FFE4DA;
Font: #212121; #ffffff; #9E9E9E;
*/
* {
  box-sizing: border-box;
}

body {
  background-color: #ffffff;
  font-family: 'Montserrat', sans-serif;
  font-size: 16px;
  font-weight: 400;
  letter-spacing: 1px;
  line-height: 1.6;
  color: #212121;
}

header {
  background-color: #ffffff;
  padding: 10px 0 4px;
  box-shadow: 0px 5px 5px 0px rgba(50, 50, 50, 0.75);
  position: fixed;
  width: 100%;
  display: inline-block;
}

main {
  padding-top: 72px;
}

footer {
  background-color: #FFECE8;
  padding: 10px;
  text-align: center;
}

h1 {
  font-size: 2.25em;
  line-height: 1.4;
}

h2 {
  font-size: 2em;
  letter-spacing: 4px;
  text-align: center;
  margin: 20px auto;
}

h3 {
  font-size: 1.75em;
  font-weight: 500;
  margin: 40px auto 10px auto;
}

h4 {
  font-size: 1.35em;

}

h5 {
  font-size: 0.75em;
  color: #9E9E9E;
  text-align: center;
}

img {
  width: 100%;
}

/* ========== Link ========== */
a {
  color: #BF491F;
  text-decoration: none; /* No underlining */
}

a:hover,
a:focus {
  color: #FFA282;
  text-decoration: underline; /* Underlining when hovering over a link */
}

a:active {
  color: #BF491F;
  text-decoration: none; /* No underlining */
}

/* ========== Buttons ========== */
.button {
  display: inline-block;
  background-color: #ffffff;
  color: #212121;
  text-transform: uppercase;
  font-weight: 500;
  font-size: 0.75em;
  letter-spacing: 3px;
  margin: 20px auto;
  padding: 10px 20px;
  border: 2px solid #BF491F;
  transition: 0.2s;
  transition-property: opacity;
}

.button:hover {
  opacity: 0.8; /* Reduces the opacity of the button to 80% */
  background-color: #FFA282;
  color: #212121;
  transition: 0.2s;
  text-decoration: none;
}

.button:active {
  color: #9E9E9E;
  text-decoration: none;
}

.button.contact {
  background-color: #BF491F;
  color: #ffffff;
}

.button.contact:active {
  background-color: #BF491F;
  color: #ffffff;
}

#portfolio .button {
  margin: 10px auto;
}

/* ========== Formatting ========== */
.container {
  margin: 0 auto;
  padding: 0 15px;
  max-width: 1200px;
}

.center {
  text-align: center;
}

.row {
  margin: 25px 0;
}

.new-section {
  margin-top: 30px;
}

/* ========== Hero section ========== */
#hero {
  background-color: #ffffff;
  display: inline-block;
  width: 100%;
}

#hero h1 {
  text-align: center;
}

/* ========== ABOUT page ========== */
.mystory-section {
  display: inline-block;
  color: #BF491F;
  font-weight: 500;
  margin: 20px auto 10px auto;
}

#about-me {
  padding: 10px 0;
  display: inline-block;
  width: 100%;
}

#skills h3 {
  border-bottom: 2px solid #212121;
  width: 250px;
}

#tools h3 {
  border-bottom: 2px solid #212121;
  width: 250px;
}

#profile-picture {
  display: inline-block;
  width: 60%;
  margin: 0 auto;
}

#skills > ul {
  list-style-type: none;
  padding: 0;
}

/* ========== Header / Navigation menu ========== */
.logo {
  width: 10%;
  max-width: 150px;
  min-width: 100px;
}

nav > ul {
  list-style-type: none;
  padding: 0;
  margin: 0;
}

nav > ul > li > a {
  padding: 0 15px;
  text-transform: uppercase;
  color: #212121;
}

nav > ul > li > a:hover, :focus {
  color: #212121;
  text-decoration: none;
}

nav > ul > li > a:active {
  border-bottom: 2px solid #BF491F;
  transition: 0.2s opacity;
}

.navtoggle li:not(:last-child) {
  display: none;
}

.navtoggle, .navtoggle.responsive {
  position: relative;
}

.navtoggle li .icon {
  position: absolute;
  right: 0;
  top: 2px;
  font-size: 30px;
}



.current-page {
  font-weight: 500;
}

.non-current-page {
  color: #9E9E9E;
}

/* ========== Footer ========== */
#contact h2{
  text-align: left;
  letter-spacing: 2px;
}

#contact {
  text-align: left;
}

.social-media > ul {
  list-style-type: none;
  padding: 0;
  text-align: right;
}

.social-media > ul > li {
  display: inline-block;
}

/* ========== Animation ========== */

@keyframes color-change-sky {
  from {fill: #CEEDFB;}
  to {fill: #372CC3;}
}

#Sky {
  animation: 15s color-change-sky infinite alternate linear;
}

@keyframes color-change-seagull {
  from {opacity: 1}
  to {opacity: 0}
}

#Seagull {
  animation: 15s color-change-seagull infinite alternate linear;
  }

@keyframes color-change-night {
  from {opacity: 0}
  to {opacity: 1}
}

#Star {
    animation: 15s color-change-night infinite alternate linear;
  }
.Moon {
      animation: 15s color-change-night infinite alternate linear;
  }

/* ========== INK TANK page ========== */
  .inktank-process {
    color: #00796B;
  }

  /* ANIL STYLE starts here */
@media only screen and (max-width: 640px) {
  .navtoggle.responsive nav {
    padding: 24px 0 0;
  }
  .navtoggle.responsive li  {
    display: block;
    padding: 10px 0;
  }

  .navtoggle.responsive li:last-child  {
    padding: 0 0 10px;
  }
}
/* ANIL STYLE starts end */

/* ==============================
Medium devices (640px and larger)
================================= */
@media only screen and (min-width: 640px) {
  body {
    font-size: 18px;
  }

  header {
    text-align: unset;
    padding: 20px 0 13px;
    font-size: 16px;
  }

  nav {
    width: auto;
    float: right;
  }

  nav > ul {
    margin: 1em 0;
  }

  nav > ul > li {
    display: inline-block;
  }

  .navtoggle li:not(:last-child) {
    display: inline-block;
  }

  .navtoggle li:last-child {
    display: none;
  }

  main {
    padding-top: 99px;
  }

  #hero {
    padding-top: 0;
  }

  #hero span {
    display: block;
  }

  #contact span {
    display: block;
  }

  .col-md-1 {
    width: 8.33%;
  }

  .col-md-2 {
    width: 16.66%;
  }

  .col-md-3 {
    width: 25%;
  }

  .col-md-4 {
    width: 33.33%;
  }

  .col-md-5 {
    width: 41.66%;
  }

  .col-md-6 {
    width: 50%;
  }

  .col-md-7 {
    width: 58.33%;
  }

  .col-md-8 {
    width: 66.66%;
  }

  .col-md-9 {
    width: 75%;
  }

  .col-md-10 {
    width: 83.33%;
  }

  .col-md-11 {
    width: 91.66%;
  }

  .col-md-12 {
    width: 100%;
  }

  [class*="col-"] {
    float: left;
    padding: 0 10px;
  }

  .row::after {
    content: "";
    clear: both;
    display: table;
  }

  .width-80 {
    width: 80%;
    margin: 0 auto;
  }

  #inktank-intro h4 {
    margin: 15px 0;
  }

  /* ==============================
  Large devices (1024px or larger)
  ================================= */
  @media only screen and (min-width: 1024px) {
    .col-lg-5 {
      width: 41.66%;
    }

    .col-lg-7 {
      width: 58.33%;
    }

  }
  /* ==============================
  X-large devices (1440px or larger)
  ================================= */
  @media only screen and (min-width: 1440px) {
    .container {
      max-width: 1200px;
      margin-left: auto;
      margin-right: auto;
    }

  }
}