@font-face {
    font-family: "Open Sans";
    src: url("../fonts/Open_Sans/OpenSans-Regular.ttf") format("truetype");
    font-weight: 400;
    font-style: normal;
}

@font-face {
    font-family: "Open Sans";
    src: url("../fonts/Open_Sans/OpenSans-SemiBold.ttf") format("truetype");
    font-weight: 600;
    font-style: normal;
}

html {
    min-height: 100%;
}

body {
    margin: 0;
    min-height: 100%;
    color: #ffffff;
    background-color: #0C8A50;
    background-image: linear-gradient(to bottom, #0C8A50, #0977BB);
    font-family: "Open Sans", "Segoe UI", sans-serif;
}

.sheet {
    box-sizing: border-box;
    max-width: 40rem;
    margin: 0 auto;
    padding: 28px 20px 72px;
}

.home {
    display: flex;
    align-items: center;
    gap: 12px;
    margin: 0 0 28px;
    color: #ffffff;
    font-size: 22px;
    font-weight: 600;
    line-height: 1;
    text-decoration: none;
}

.home svg {
    width: 48px;
    height: 48px;
    flex: 0 0 auto;
}

h1 {
    margin: 0 0 16px;
    font-size: 32px;
    font-weight: 600;
    line-height: 1.15;
}

h2 {
    margin: 28px 0 8px;
    font-size: 20px;
    font-weight: 600;
    line-height: 1.25;
}

p {
    margin: 0 0 12px;
    font-size: 17px;
    line-height: 1.45;
}

a:link,
a:visited {
    color: #ffffff;
}

p a {
    text-underline-offset: 3px;
}

a:focus-visible {
    outline: 2px solid #ffffff;
    outline-offset: 3px;
}

.open:link,
.open:visited,
.open:hover,
.open:active {
    color: #ffffff;
    text-decoration: none;
}

.open {
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    margin: 8px 0 16px;
    padding: 0 16px;
    border: 2px solid rgba(255, 255, 255, 0.85);
    color: #ffffff;
    font-size: 16px;
    text-decoration: none;
}

.exercises {
    list-style: none;
    margin: 0 0 8px;
    padding: 0;
}

.exercises a {
    display: flex;
    align-items: center;
    min-height: 44px;
    border-bottom: 1px solid rgba(255, 255, 255, 0.35);
    text-decoration: none;
}

.exercises a:hover,
.open:hover,
.home:hover {
    background: rgba(255, 255, 255, 0.08);
}

.opens {
    display: flex;
    flex-wrap: wrap;
    gap: 8px;
    margin: 8px 0 16px;
}

.opens .open {
    margin: 0;
}

cite {
    font-style: italic;
}

.books {
    list-style: none;
    margin: 0 0 8px;
    padding: 0;
}

.books li {
    margin: 0;
    padding: 12px 0;
    border-bottom: 1px solid rgba(255, 255, 255, 0.35);
}

.books a {
    font-weight: 600;
    text-underline-offset: 3px;
}

.books p {
    margin: 6px 0 0;
    font-size: 16px;
}

.lang-switch {
    display: flex;
    gap: 8px;
    margin: 0 0 22px;
}

.lang-switch button,
.lang-switch a {
    flex: 0 0 auto;
    display: inline-flex;
    align-items: center;
    min-height: 44px;
    padding: 0 16px;
    border: 2px solid rgba(255, 255, 255, 0.85);
    background: transparent;
    color: #ffffff;
    font: inherit;
    font-size: 16px;
    text-decoration: none;
    cursor: pointer;
}

.lang-switch button.is-on,
.lang-switch a.is-on,
.lang-switch a.is-on:link,
.lang-switch a.is-on:visited {
    background: #ffffff;
    color: #0C8A50;
}