*,
*::before,
*::after {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
}

:root {
    --clr-brand-orange: #D97111;
    --clr-brand-green: #019546;

    --clr-dark: #2B1705;
    --clr-mid: #F59A47;
    --clr-light: #F3C499;

    --clr-arrow-disabled: #808080;
    --clr-arrow-activive: #1564FE;
    --clr-footer: #E5E5E5;
    --clr-bg-grey: #F5F5F5;
    --clr-bright-text: #FFFFFF;
    --clr-bright-green: #4DD486;
    --clr-bg-warm: #F5E8DC;
    --clr-bg-cool: #DFEBE4;
    --clr-bg-catogories: #E4EBE7;
}

html {
    font-family: Lato, -apple-system,'Open Sans', 'Helvetica Neue',  sans-serif;
    font-size: 1rem;
    font-weight: 400;
    line-height: 135%;
}

body {
    text-align: left;
    color:#2B1705;
    background: var(--clr-bg-grey);
}

img {
    display: block;
}

ul {
    list-style: none;
}

a {
    text-decoration: none;
}

p {
    display: block;
}

.btn {
    font-size: 1.125rem;
    display: block;
    background: var(--clr-brand-green);
    border-radius: 3px;
    border: none;
    width:100%;
    padding: 0.625rem 2.5em;
    max-width: 350px;
    margin: auto;
    cursor: pointer;
}

.btn a {
    display: block;
    color:var(--clr-bright-text);
    max-width: 350px;
    width: 100%;
    height: 100%;
}

.container {
    padding: 0 1.25rem;
}

h2,
h3{
    text-align: center;
}

h2 {
    line-height: 135%;
    font-weight: 600;
    font-size: 1.35rem;
}

svg {
    display: block;
}

@media(min-width: 375px) {
    .container {
        padding: 0 1.75rem;
    }
}

@media(min-width: 1024px) {
    html {
        font-size: 1.125rem;
    }
}

/* header */
header {
    background: var(--clr-bg-warm);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    max-width: 816px;
    height: 70px;
    margin: auto;
}

#logo {
    width: 181px;
}
#log-in {
    font-family: "Noto Sans TC", Lato, -apple-system,'Open Sans', 'Helvetica Neue',  sans-serif;
    font-weight: 500;
    letter-spacing: -0.005em;
    text-align: center;
}

nav a {
    color:#2B1705;
    transition: color 500ms, font-weight 500ms;
}
nav a:hover {
    color: var(--clr-brand-green);
    font-weight: 700;
}

/* main */
/* sticky-header */
.header-sticky {
    position: fixed;
    top: 0;
    background: var(--clr-bg-grey);
    height: 60px;
    z-index: 5;
    width: 100%;
    padding: 0.4rem 0;
    transition: all 500ms;
}

.sticky-container {
    display: flex;
    align-items: center;
    justify-content: space-between;
    width: 100%;
    max-width: 816px;
    margin: auto;
}

.header-sticky,
.sticky-header-left,
.sticky-header-right {
    display: flex;
    align-items: center;
}

.sticky-logo {
    width: 120px;
}

#sticky-btn {
    padding: 0.5rem 1em;
}

#sticky-btn a {
    font-size: 0.75rem;
    line-height: 1.2;
}

.hide {
    opacity: 0;
    top: -100%;
}

.show {
    opacity: 1;
    top: 0;
}

@media(min-width: 360px) {
    #sticky-btn a {
        font-size: 1rem;
    }
}

@media(min-width: 640px) {
    .sticky-logo {
        width: 140px;
    }
    #sticky-btn {
        padding: 0.5rem 1.5em;
    }
}
@media(min-width: 768px) {
    .sticky-container {
        padding: 0 3rem;
    }
}

/* hero */
.hero {
    height: fit-content;
    background: linear-gradient(189.95deg, #2B1705 47.48%, #4DD486 88.69%);
    overflow: visible;
    font-size: 1.125rem;
    line-height: 143%;
}

.hero-container {
    display: flex;
    flex-direction:column;
    align-items: center;
    max-width: 1150px;
    width: 100%;
    margin: 0 auto;
    padding-top: 37px;
}

#hero-img {
    width: 100%;
    max-width: 28rem;
    margin: 2rem 0 -2.5rem;
}

.hero-text {
    color: #FFFFFF;
    letter-spacing: 0.03em;
}

.hero-text h1,
.hero-intro {
    margin: 0 auto;
}

.hero-text h1 {
    text-align: center;
    min-width: 100%;
    max-width: 459px;
    font-size: 1.75em;
    font-weight: 800;
    line-height: 1.2;
}

.hero-intro {
    margin-top: 25px;
    width: auto;
    line-height: 135%;
    font-weight: 300;
    font-size: 1rem;
}

.hero-text button {
    margin-top: 35px;
}

button a {
    font-family: Lato;
    font-size: 20px;
    font-weight:500;
}


@media(min-width: 361px)
  and (max-width: 476px) {
    .hero-text h1 {
      text-align: left;
    }
}


@media(min-width: 490px) {
    .hero-intro {
        padding: 0 2rem;
    }
}

@media(min-width: 540px) {
    .hero-text h1 {
      margin-left: -4rem;
      margin-right: -4rem;
  
    }
  }

@media(min-width: 540px) 
  and (max-width: 739px) {
      .hero-container {
          padding-left: 20vw;
          padding-right: 20vw;
      }
      .hero-intro {
          padding: 0;
      }
      #hero-img {
        width: calc(100% - 1.5rem);
    }
}

@media(min-width: 600px) {
    .hero-text h1 {
      margin-left: -2.5rem;
      margin-right: -2.5rem;
  
    }
  }

@media(min-width: 670px) {
    .hero-text h1 {
      margin-left: -1.5rem;
      margin-right: -1.5rem;
  
    }
}

@media(min-width: 740px) {
    .hero-container {
        flex-direction: row-reverse;
        align-items:flex-start;
        justify-content: space-between;
    }
}

@media(min-width: 740px)
and (max-width: 767px) {
    #hero-img {
        width: 270px;
        }  
}

@media(min-width: 768px) {
    .hero {                          
        background: linear-gradient(210.88deg, #2B1705 47.95%, #4DD486 99.52%);
    }

    #hero-img {
        margin: -0.5rem 0 -2.5rem;
        min-width: 360px
    }

    .hero-text h1 {
        text-align: left;
        font-size: 1.8em;
        margin: 0 auto;
    }

    .hero-text .btn {
        padding: 0.635rem 4rem;
        margin-left: 0;
    }
    .hero-intro {
        margin-left: 0;
        padding: 0;
    }

    .hero-text{
        min-width: 326px;
        margin-left: 2rem;
    }    
}

@media(min-width:800px) {
    .hero-text {
        margin-left: 3rem;
    }
}

@media(min-width: 1024px) {
    .hero-text {
        margin-left: 4rem;
        margin-right: 3rem; 
    }
    
    .hero-text h1 {
        font-size: 2.25em;
    }

    .hero-intro {
        max-width: 430px;
    }
    #hero-img {
        margin-left: 2rem;
        margin-right: 2rem;
    }
}


/* features */

.feature-container {
    background: var(--clr-bg-warm);
    padding-top: 70px;
    padding-bottom: 35px;
}

.features {
    margin-bottom: 32px;
}

.feature-icons {
    display: flex;
    justify-content: center;
    margin: auto;
}

.features svg * {
    fill: var(--clr-dark);
}

.feature-headline {
    margin: 0 32px 39px;
}

h3 {
    font-size: 1.1rem;
    font-weight: 600;
    margin: 1.25rem 0 0.75rem;
}

.feature-text {
    max-width: 430px;
    margin: auto;
}
.feature-wrapper {
    width: fit-content;
    margin: auto;
}

@media(min-width: 450px) {
    .features {
        display: flex;
        justify-content: center;
        align-items: center;
    }
    .feature-icons {
        width: 90px;
        flex-shrink: 0;
        margin-right: 2rem;
        margin-left: 0;
    }
    .feature-headline {
        margin: 0 auto 39px;
    }
}

@media (min-width: 450px) 
    and (max-width: 767px) {
        .features h3 {
            text-align: left;
        }
}

@media(min-width: 768px) {

    .feature-container {
        padding-top: 85px;
    }
    .features {
        display: block;
    }
    .feature-icons{
        margin: auto;
    }
    .feature-wrapper {
        display: flex;
        justify-content: center;
    }
    .feature-mid-column {
        margin: 0 2rem;
    }
}

@media(min-width: 780px) {
    .feature-mid-column {
        margin: 0 3rem;
    }
}

@media(min-width: 1024px) {
    .feature-container {
        padding-right: 4rem;
        padding-left: 4rem;
    }
    .feature-text {
        max-width: 310px;
    }
}

/* benefits */

.body-text {
    margin: 1.625rem auto 2.5rem;
    max-width: 430px;
}

.growth .body-text {
    margin-bottom: -2rem;
}

.dollar-sign {
    color: var(--clr-brand-orange);
}

.amount {
    color: var(--clr-brand-green);
    font-weight: 700;
}

.benefit-container {
    padding-top: 65px;
}

.benefits {
    margin: 0 auto 40px;
    display: grid;
    grid-template-columns: repeat(12, 1fr);
    grid-template-rows: repeat(4. auto);
    grid-gap: 1rem;
}
.benefits h2 {
    grid-area: 1/1/2/13;
}
.benefit-para {
    grid-area: 2/1/3/13;
}
.benefit-btn{
    margin-bottom: 2.5rem;
    grid-area: 3/1/4/13;
}
.benefits img{
    width: 100%;
    grid-area: 4/2/5/12;
}

#app-summary {
    max-width: 350px;
}

#app-community {
    max-width: 270px;
}

.free-trial {
    background: var(--clr-bg-cool);
    padding-top: 35px;
    padding-bottom: 35px;
}

.frame {
    border: 2px var(--clr-bright-green) solid;
    padding: 0 1.125rem 26px;
    margin: 0 auto;
    max-width: 400px; 
}

#trial-text {
    margin-bottom: 1.5rem;
}

.frame .btn {
    padding: 0.625rem 2rem;
    margin: 0 auto;
}

#book-stacks {
    max-width: 600px;
    margin-bottom: -3.5rem;
    z-index: 1;
    grid-area: 4/1/5/13;
    margin-top: -1.5rem;
}

.app-ui {
    margin: 0 auto;
}

@media(min-width: 320px) {
    h2 {
        font-size: 1.5rem;
    }
    h3 {
        font-size: 1.2rem;
    }
}

@media(min-width: 375px) {
    #community {
        min-width: 330px;
    }    
}

@media(min-width: 640px) {
        .growth .body-text {
        margin-bottom: -18%;
    }
}
@media(min-width:640px)
  and (max-width: 767px) {
      #book-stacks {
          margin-top: 0;
      }
  }

@media(min-width: 768px) {
    h2 {
        font-size: 1.625rem;
    }
    .benefits {
        grid-template-rows: 3.5rem 9rem 3rem auto;
        grid-column-gap: 3rem;
        margin-bottom: 4rem;
    }
    .benefits-btn {
        margin-bottom: 0;
    }
    .benefit-btn,
    .benefit-para:not(.b-text-3) {
        justify-self: start;
        margin: unset;
    }

    .b-headline-1,
    .b-headline-3 {
        grid-area: 1/1/2/13;
    }
    .b-text-1 {
        margin-top: 0;
        grid-area: 2/2/3/7;
    }
    .b-headline-2 {
        grid-area: 1/1/2/13;
    }
    .b-text-3 {
        margin-top: 0;
        grid-area: 2/2/3/9;        
    }
    .b-text-2{
        margin-top: 0;
        grid-area: 2/6/3/12;
    }
    #app-summary {
        grid-area: 2/7/5/12;
    }
    #app-community {
        grid-area: 2/2/5/6;
    }
    #book-stacks {
        transform: unset;
        grid-area: 2/3/5/11;
        margin-top: unset;
    }
    .b-1-btn {
        grid-area: 3/2/4/7;
    }
    .b-2-btn {
        grid-area: 3/6/4/12;
    }
}

@media(min-width: 1024px) {
    .benefits {
        max-width: 1120px;
        grid-column-gap: 5rem;
        grid-row-gap: 1.5rem;
    }
}

/* social approval */

.social-approval {
    background: var(--clr-bg-warm);
    padding: 48px 0;
}

.social-approval .body-text{
    max-width: 550px;
}

.mobile-user-review {
    max-width: 500px;
    margin: auto;
}

.desktop-user-review {
    display: none;
}

.mobile-user-info {
    display: flex;
    align-items: center;
}

.mobile-avatar,
.starts-and-names {
    display: inline-block;
}

.mobile-avatar {
    width: 4.5rem;
    margin-right: 17px;
    border: none;
    border-radius: 50%;
}

.star {
    display: inline-block;
    margin-right: -3px;
    fill: var(--clr-mid);
}

.mobile-user-name,
.desktop-user-name {
    font-size: 1.125rem;
    font-weight: 400;
    letter-spacing: 0.03em;
}

.mobile-user-review p {
    margin-top: 1.125rem;
}

@media(min-width: 1024px) {
    .mobile-user-review {
        display: none;
    }
    .desktop-user-review {
        display: flex;
        align-items: flex-start;
        justify-content: center;
        margin: auto;
        max-width: 45rem;
    }
    .desktop-avatar {
        width: 5.5rem;
        margin-right: 2rem;
        border: none;
        border-radius: 50%;
    }
    .starts-and-names {
        display: flex;
    }
    .desktop-user-name {
        margin-right: 0.75rem;
    }
    .desktop-user-review p {
        margin-bottom: 3rem;
    }
}

/* book display */

.catogories {
    background: var(--clr-bg-catogories);
    padding-bottom: 80px;
}

.popular {
    padding-top: 80px;
}
.new {
    padding-top: 40px;
    padding-bottom: 40px;
}

.book-slider-with-arrows-container {
    display: flex;
    margin: auto;
    overflow: hidden;
}

.book-slider-with-arrows {
    display: flex;
    align-items: flex-start;
    margin: auto;
    overflow: hidden;
    height: 348px;
}

.arrow {
    border: none;
    display: flex;
    background: transparent;
    height: 100%;
    width: 4rem;
}

.book-slider-nav-arrow-right {
    justify-content: flex-end;
}

.left-arrow-icon,
.right-arrow-icon {
    cursor: pointer;
    margin-top: 6.5rem;
    fill: var(--clr-arrow-activive);
}

.book-slider-nav-arrow-left:disabled .left-arrow-icon,
.book-slider-nav-arrow-right:disabled .right-arrow-icon {
    fill: var(--clr-arrow-disabled);
}

.book-display {
    margin-top: 40px;
    overflow-x: scroll;
    overflow-y: hidden;
    width: 650px;
    height: 318px;
    position: relative;
}

.book-display-container {
    display: flex;
    overflow: hidden;
    position: absolute;
    transition: all 0.5s ease-in-out;
}

.books {
    height: 176px;
}

.book-card {
    display: inline-flex;
    flex-direction: column;
    margin-right: 27px;
}
.book-card:last-child {
    margin-right: 0;
}

.book-info {
    width: 140px;
    margin-top: 20px;
    margin-bottom: 10px;
}

.book-title {
    font-size: 0.8rem;
    line-height: 1.1rem
}

.book-title span {
    font-size: 0.67rem;
    font-weight: 600;
}

.author {
    margin-top: 0.3rem;
    font-size: 0.75rem;
    line-height: 0.85rem;
}

.unlock {
    text-align: center;
    margin-top: 14px;
    font-size: 1.125rem;
}

.book-card-link {
    background: var(--clr-brand-green);
    height: 176px;
    width: 200px;
    padding: 28px 45px;
}

.book-card-link a {
    color: var(--clr-bright-text);
    border-bottom: 1px solid var(--clr-bright-text);
    font-size: 17.5px;
    line-height: 2;
    padding-bottom: 3px;
}

@media(max-width: 767px) {
    .arrow {
        display: none;
    }
}

@media(min-width: 768px) {
    .book-display{
        margin-right: auto;
        margin-left: auto;
    }

}
@media(min-width: 1024px) {
    .book-display {
        width: 800px;
    }
}

/* footer */

footer {
    padding: 45px 0 50px;
    background: var(--clr-dark);
    color: var(--clr-footer);
    line-height: 200%;
    letter-spacing: 0.
}

footer a {
    color:var(--clr-footer);
}

.footer-links h5 {
    font-size: 1rem;
    text-transform: uppercase;
    font-weight: 400;
    margin: 25px 0 20px;;
}

.footer-links-wrapper {
    margin: auto;
    display: flex;
    justify-content: space-between;
    flex-wrap: wrap;
    margin-bottom: 40px;
    max-width: 850px;
}

.footer-links {
    padding-right: 40px;
}

.footer-links ul {
    font-weight: 300;
}


.badge-button {
    margin-top: 30px;
    width: 118px;
}


.social-media-wrapper {
    margin-bottom: 25px;
    display: flex;
    justify-content: center;
}

.social-media {
    height: 28px; 
}

.social-media svg {
    display: inline-block;
    margin: 0 5px;
    fill: var(--clr-footer);
}

.license {
    display: block;
    font-size: 0.875rem;
    text-align: center;
}

#attributions a:hover {
    border-bottom:  1px solid var(--clr-bright-text);
    line-height: 1.5;
}

@media(min-width:307px)
  and (max-width:349px) {
      .footer-links {
        padding-right: 70px;
      }
  }

@media(min-width:474px)
  and (max-width:631px) {
      .footer-badges li {
          display: inline-block;
          margin-right: 2rem;
      }
      .badge-button {
        margin-top: 15px;
      }
  }