* {
    box-sizing: border-box;
}

body {
    margin: 0;
    font-family: "Hiragino Kaku Gothic ProN";
    /* color: #e8e6e3;     のちに追加予定*/
}

a {
    text-decoration: none;
}

.container {
    width: 100%;
    padding: 0 15px;
    margin: 0 auto;
    background-color: #181a1b00;
}

.top-wrapper {
    padding: 180px 0 100px 0;
    background-image: url(https://github.com/FireSepicHub-14/firesepichub-14.github.io/blob/main/pngs/top-test-1.png?raw=true);
    background-size: cover;
    color: white;
    text-align: center;
}

.top-wrapper h1 {
    opacity: 0.7;
    font-size: 45px;
    letter-spacing: 5px;
}

.top-wrapper p {
    opacity: 0.7;
    font-size: 16px;
    margin-bottom: 40px;
}

.btn-wrapper {
    text-align: center;
}

.btn-wrapper p {
    margin-bottom: 20px;
}

.signup {
    background-color: #239b76;
}

.youtube {
    background-color: #a1050d;
    margin-right: 10px;
}

.twitter {
    background-color: #55acee;
}

.btn {
    padding: 8px 24px;
    color: white;
    display: inline-block;
    opacity: 0.8;
    border-radius: 4px;
    text-align: center;
}

.btn:hover {
    opacity: 1;
}

.fa {
    margin-right: 5px;
}

header {
    height: 65px;
    width: 100%;
    background-color: rgba(34, 49, 52, 0.9);
    position: fixed;
    top: 0;
    z-index: 10;
}

.logo {
    width: 124px;
    margin-top: 20px;
}

.header-left {
    float: left;
}

.header-right {
    float: right;
    margin-right: -25px;
}

.header-right a {
    line-height: 65px;
    padding: 0 25px;
    color: white;
    display: block;
    float: left;
    transition: all 0.5s;
}

.header-right a:hover {
    background-color: rgba(255, 255, 255, 0.3);
}

.lesson-wrapper {
    height: 580px;
    padding-bottom: 80px;
    padding-left: 5%;
    padding-right: 5%;
    background-color: #181a1b;
    text-align: center;
}

.heading {
    padding-top: 80px;
    padding-bottom: 50px;
    color: #5f5d60;
}

.heading h2 {
    font-weight: normal;
}

.lesson {
    float: left;
    width: 25%;
}

.lesson-icon {
    position: relative;
}

.lesson-icon p {
    position: absolute;
    top: 37%;
    width: 100%;
    color: white;
}

.text-contents {
    width: 80%;
    display: inline-block;
    margin-top: 15px;
    font-size: 13px;
    color: #b3aeb5;
}

.heading h3 {
    font-weight: normal;
}

.message-wrapper {
    border-bottom: 1px solid #f716ac;
    background-color: #181a1b;
    padding-bottom: 80px;
    text-align: center;
}

.message {
    padding: 15px 40px;
    background-color: #5dca88;
    cursor: pointer;
    box-shadow: 0px 7px #1a7940;
}

.message:active {
    position: relative;
    top: 7px;
    box-shadow: none;
}

footer img {
    width: 125px;
}

footer {
    background-color: #181a1b;
}

footer p {
    color: #d4f1e3;
    font-size: 12px;
}

footer {
    padding-top: 30px;
    padding-bottom: 20px;
}

.menu-icon {
    color: white;
    float: right;
    font-size: 25px;
    padding: 21px 0;
    display: none;
}

.content {
    display: flex;
    justify-content: center;
    align-items: center;
}

.right {
    margin-right: auto;
}

.clear {
    clear: left;
}

@media all and (max-width: 1000px) {
    .lesson {
        width: 50%;
        margin-bottom: 50px;
    }
    .lesson-wrapper {
        height: 990px;
    }
    footer {
        text-align: center;
    }
}

@media all and (max-width: 750px) {
    .top-wrapper h1 {
        font-size: 32px;
    }
    .heading h2 {
        font-size: 20px;
    }
}

@media all and (max-width: 670px) {
    .header-right {
        display: none;
    }
    .menu-icon {
        display: block;
    }
    .top-wrapper .btn {
        width: 100%;
    }
    .twitter {
        margin-top: 10px;
    }
    .top-wrapper {
        text-align: left;
    }
    .top-wrapper h1 {
        font-size: 24px;
    }
    .top-wrapper p {
        font-size: 14px;
    }
    .lesson {
        width: 100%;
    }
    .lesson-wrapper {
        height: 1700px;
    }
    .message-wrapper .btn {
        width: 100%;
    }
}