* {
  font-family: var(--font);
  box-sizing: border-box;
  margin: 0;
  padding: 0;
}

.button, .quiz-options button {
    display: flex;
    align-items: center;
    justify-content: flex-start;
    gap: .75rem;
    padding: .75rem 1.5rem;
    border-radius: var(--border-radius);
    text-decoration: none;
    transition-duration: .15s;
}
.button svg, .quiz-options button svg {
    height: 1.25rem;
    width: 1.25rem;
}
.button-blue, .quiz-options button {
    background-color: var(--button-color);
    border: 2px solid var(--button-color);
    color: var(--background-color);
}
.button-blue:hover, .quiz-options button:hover {
    background-color: var(--background-secondary-color);
    color: var(--button-color);
}
.button-gray {
    background-color: var(--border-color);
    border: 2px solid var(--border-color);
    color: var(--primary-color);
}
.button-gray:hover {
    color: var(--primary-color);
    background-color: var(--background-color);
}

.header {
    padding: 1rem 0;
    border-bottom: 1px solid var(--border-color);
    background-color: var(--background-color);
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
}
.header-wrapper {
    display: flex;
    align-items: center;
    justify-content: space-between;
    flex-wrap: wrap;
    gap: 1rem;
}
.header-login {
    display: flex;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
    gap: .75rem 1rem;
}
.header-login p {
    margin-bottom: 0;
    line-height: 1.25;
}
.header-menu {
    display: flex;
    align-items: center;
    gap: 1rem;
}
.header-menu a {
    color: var(--primary-color);
    font-weight: 500;
    text-decoration: none;
}
.header .navbar-toggler {
    padding-right: 0;
    padding-top: 0;  
    margin-top: 0;
    border: none !important;
    box-shadow: none !important;
    outline: none !important;
    display: none;
}
.header .animated-icon {
  width: 30px;
  height: 20px;
  position: relative;
  margin: 0px;
  transform: rotate(0deg);
  cursor: pointer;
  transition: 0.5s ease-in-out;
}
.header .animated-icon span {
  display: block;
  position: absolute;
  height: 3px;
  width: 100%;
  border-radius: 9px;
  opacity: 1;
  left: 0;
  transform: rotate(0deg);
  transition: 0.25s ease-in-out;
  background: var(--highlight-color);
}
.header .animated-icon span:nth-child(1) {
  top: 0px;
}
.header .animated-icon span:nth-child(2) {
  top: 10px;
}
.header .animated-icon span:nth-child(3) {
  top: 20px;
}
.header .animated-icon.open span:nth-child(1) {
  top: 11px;
  transform: rotate(135deg);
}
.header .animated-icon.open span:nth-child(2) {
  opacity: 0;
  left: -60px;
}
.header .animated-icon.open span:nth-child(3) {
  top: 11px;
  transform: rotate(-135deg);
}
@media (max-width: 768px) {
    .header {
        position: unset;
    }
    .header-wrapper {
        align-items: center;
        gap: .5rem;
    }
    .header .navbar-toggler {
        display: block;
    }
    .header-login.loggedin {
        flex-direction: column;
    }
    .header-login {
        display: none;
        width: 100%;
        padding-top: .5rem;
    }
    .header .button {
        padding: .33rem .75rem;
    }
    .header-login.open {
        display: flex;
    }
    .header-login p {
        text-align: center;
        font-size: 15px;
        line-height: 1.15;
    }
}


h1, h2, h3 {
    font-weight: 600;
    margin-bottom: 0;
}
main {
    min-height: 100dvh;
    display: flex;
    flex-direction: column;
    justify-content: center;
    gap: 3.5rem;
    padding: 8.5rem 0;
}
.section-title {
    margin-bottom: 1.75rem;
    text-align: center;
}
.section-bottom {
    margin-top: 1.5rem;
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: .75rem;
}
@media (max-width: 768px) {
    main {
        min-height: unset;
        padding: 2.25rem 0;
        gap: 2.25rem;
    }
}

.lectures-info {
    max-width: 800px;
    width: 100%;
    margin: 0 auto;
    padding: 2.5rem;
    background-color: var(--background-secondary-color);
    border-radius: var(--border-radius);
    display: flex;
    justify-content: flex-start;
    gap: 2rem;
}
.lectures-info img {
    max-width: 200px;
    object-fit: scale-down;
    width: 100%;
    flex-shrink: 0;
}
.lectures-info-inner {
    width: 100%;
}
.lectures-wrapper {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: .75rem;
    width: 100%;
}
.lectures-item:not(.active) {
    background-color: var(--background-color);
    color: var(--highlight-color);
}
.lectures-item:not(.active):hover {
    background-color: var(--background-secondary-color) !important;
}
.lectures-item-checkbox {
    border: 2px solid var(--highlight-color);
    background-color: var(--background-color);
    border-radius: var(--input-radius);
    width: 1.5rem;
    height: 1.5rem;
    display: block;
    position: relative;
}
.lectures-item-checkbox svg {
    opacity: 0;
    visibility: hidden;
    transition-duration: .15s;
    position: absolute;
    top: 50%;
    left: 50%;
    transform: translate(-50%, -50%);
    width: 1rem;
    height: 1rem;
    stroke: var(--highlight-color);
}
.lectures-item.active .lectures-item-checkbox svg {
    opacity: 1;
    visibility: visible;
}
@media (max-width: 768px) {
    .lectures-info-inner > * {
        text-align: center;
    }
    .lectures-info {
        max-width: 100%;
        flex-direction: column;
        align-items: center;
        padding: 1.5rem;
    }
    .lectures-wrapper {
        grid-template-columns: 1fr;
    }
}

.books-wrapper {
    padding: 2.5rem;
    background-color: var(--background-secondary-color);
    border-radius: var(--border-radius);
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 1.5rem;
}
.books-item {
    max-width: 200px;
    width: 100%;
    text-decoration: none;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: space-between;
}
.books-item span {
    margin-top: 1rem;
    display: block;
    text-align: center;
    color: var(--primary-color);
}
@media (max-width: 768px) {
    .books-wrapper {
        flex-direction: column;
        align-items: center;
    }
}



.quiz-info, .quiz-top, .form-wrapper {
    width: 100%;
    margin: 0 auto;
    background-color: var(--background-secondary-color);
    border-radius: var(--border-radius);
    display: flex;
    justify-content: center;
    align-items: center;
}
.quiz-info {
    max-width: 800px;
    flex-direction: column;
    gap: 1.5rem;
    padding: 2.5rem;
}
.quiz-question {
    text-align: center;
}
.quiz-options {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 1.5rem;
}
.quiz-options button {
    width: 200px;
    justify-content: center;
}
.quiz-options:empty, .quiz-feedback:empty {
    display: none;
}
.quiz-feedback {
    color: red;
}
.quiz-top {
    max-width: 800px;
    padding: 1rem;
    gap: .5rem 1.5rem;
    width: 100%;
    margin-bottom: .25rem;
    flex-wrap: wrap;
}
.quiz-top > div {
    background-color: var(--background-color);
    border-radius: var(--border-radius);
    padding: .75rem 1.5rem;
}
@media (max-width: 768px) {
    .lectures-info-inner > * {
        text-align: center;
    }
    .quiz-info {
        max-width: 100%;
        padding: 1.5rem;
    }
    .quiz-top {
        max-width: 100%;
    }
    .quiz-options {
        grid-template-columns: 1fr;
        gap: .5rem;
    }
    .quiz-feedback {
        text-align: center;
    }
}

.form-wrapper {
    flex-direction: column;
    gap: 1rem;
    padding: 2.5rem;
    max-width: 450px;
}
.form-wrapper .form-input {
    height: 52px;
    width: 100%;
    border: 1px solid var(--background-color);
    border-radius: var(--input-radius);
    padding: 1.5rem;
}
.form-wrapper .form-input:focus {
    box-shadow: none;
    outline: none;
    border-color: var(--highlight-color);
}
.form .flash {
    color: red;
    margin-bottom: .5rem;
}
@media (max-width: 768px) {
    .form-wrapper {
        max-width: 100%;
        padding: 1.5rem;
    }
}