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

:root {
    --primary: #ff0066;
    --bg-00: #fff;
    --bg-01: #000;
    --bg-02: #ddd;
    --ff: system-ui, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, Oxygen, Ubuntu, Cantarell, 'Open Sans', 'Helvetica Neue', sans-serif;
}

/* @media (prefers-color-scheme: dark) {
    :root {
        --bg-00: #000;
        --bg-01: #fff;
        --bg-02: #333333;
    }
} */

::selection {
    background: var(--bg-01);
    color: var(--bg-00);
}

::-webkit-scrollbar {
    display: none;
}

body {
    background: var(--bg-00);
    font-size: 16px;
    font-family: var(--ff);
    color: var(--bg-01);
}

a {
    text-decoration: none;
}

svg {
    fill: var(--bg-01);
}
img {
    width: 100%;
}

/* header */
header {
    position: sticky;
    position: -webkit-sticky;
    top: 0;
    left: 0;
    z-index: 4;
    backdrop-filter: blur(100px);
}

header .container {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 0.7rem 1rem;
}

header .container .left {
    display: flex;
    align-items: center;
    gap: 2.5rem;
}

header .container .right {
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

header .logo {
    font-size: 1.6rem;
    font-weight: bolder;
    color: var(--bg-01);
}

/* buttons */
.btn-0 {
    padding: 0.5rem 1.5rem 0.5rem 1.5rem;
    border-radius: 50px;
    border: 1px solid var(--bg-01);
    background: var(--bg-01);
    font-size: 1em;
    color: var(--bg-00);
    display: flex;
    gap: 0.3rem;
    height: 40px;
    font-weight: 500;
}

.btn-0 svg {
    fill: var(--bg-00) !important;
    scale: 0.9;
}

nav {
    display: flex;
    gap: 1.5rem;
}
nav a {
    color: var(--bg-01);
    font-weight: 500;
}

/* sections */
.section-1 {
    position: relative;
    top: 0rem;
    padding: 0 1rem;
}

/* teacher */
.subject {
    width: 100%;
    background: url(./cover.jpg);
    background-size: cover;
    height: 600px;
    text-align: center;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-direction: column;
    border-radius: 1rem;
    color: #fff;
}
.subject .grades {
    display: flex;
    padding: 1rem;
    gap: 1rem;
    flex-wrap: wrap;
    align-items: center;
    justify-content: center;
}
.subject .grades .grade {
    background: #fff;
    color: #000;
    border-radius: 50%;
    padding: 1rem;
    font-size: 1.4em;
    font-weight: bold;
    width: 80px;
    height: 80px;
    display: flex;
    align-items: center;
    justify-content: center;
}
.subject .instructor {
    position: relative;
    top: -1.3rem;
    font-size: 1.6em;
}
.subject-title {
    max-width: 1200px;
    margin: 0 auto;
    padding: 1rem;
    font-size: 7em;
}
.teacher {
    padding: 4rem 1rem;
    border-bottom: none;
    display: flex;
    gap: 2rem;
    max-width: 1200px;
    margin: 0 auto;
    align-items: center;
    flex-wrap: wrap;
    justify-content: center;
}

.teacher .info {
    display: flex;
    flex-direction: column;
}
.teacher .info p {
    font-size: 1em;
}
.teacher .info .title {
    background: var(--bg-01);
    color: var(--bg-00);
    padding: 0.3rem 0.7rem;
    border-radius: 50px;
    font-size: 1em;
    width: fit-content;
    margin-bottom: 0.5rem;
    font-weight: 500;
}
.teacher .info .name {
    font-size: 2em;
    font-weight: bold;
}

.teacher img {
    width: 120px;
    height: 120px;
    border-radius: 50%;

}

/* section-2 */
.section-2 .container {
    padding: 1rem;
    max-width: 800px;
    margin: 0 auto;
    border-radius: 1rem;
    color: var(--bg-01);
    font-weight: 500;
    margin-bottom: 3rem;
}
.section-2 .container .item {
    display: flex;
    gap: 1rem;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 1rem;
    border-bottom: 1px solid var(--bg-02);
    padding: 1rem;
    font-size: 1.2em;
}

/* footer */
footer {
    padding: 1rem;
}
footer .container {
    padding: 1rem;
    max-width: 1000px;
    margin: 0 auto;
    background: var(--bg-01);
    border-radius: 1rem;
    color: var(--bg-00);
    text-align: center;
}
footer .container .owner-info {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
    align-items: center;
}
footer .container a {
    color: var(--bg-00);
}


/* MEDIA */
@media screen and (max-width: 540px) {
    nav {
        display: none;
    }
    .subject-title {
        font-size: 3em;
    }
    .subject .instructor {
        font-size: 1.2em;
    }
    .subject .grades .grade {
        width: 60px;
        height: 60px;
    }
    .section-2 .container .item {
        display: flex;
        flex-direction: column;
    }
    footer .container .owner-info {
        font-size: 0.8rem;
        margin-right: 0.6rem;
    }
}