* {
    box-sizing: border-box;
}

body {
    background: #fefefe;
    margin: 0;
    scrollbar-width: thin; /* auto (default), thin, none */
    scrollbar-color: #333 #eee; /* thumb color, track color */
}

.card {
    background: #fff;
    border-radius: 14px;
    box-shadow: 0 8px 25px rgba(0,0,0,0.12);
    padding: 26px;
    display: flex;
    flex-direction: column;
    margin-bottom: 10px;
    border: 1px solid rgb(189, 189, 189);
}

.question_img {
    display: flex;
    justify-content: center;
    align-items: center;
    margin: 10px 0px;
    max-width: 100%;
}

.question_img img {
    max-width: 100%;
}

@media (max-width: 768px) {
    .question-container {
        width: 90% !important;
    }
    .question_img {
        max-width:100%;
    }
    .question_img img {
        width: 100%;
        height: auto !important; 
    }
}

.question-container {
    width: 80%;
    max-width: 900px;
    margin: 0 auto 30px auto;
}

.question-container h2 {
    margin-bottom: 12px;
    font-size: 20px;
    font-weight: 600;
    color: #222;
}

.expandable {
    background: #fff;
    border-radius: 10px;
    box-shadow: 0 4px 15px rgba(0,0,0,0.12);
    padding: 14px 18px;
    cursor: pointer;
    display: flex;
    align-items: center;
    transition: box-shadow 0.3s ease;
    margin-bottom: 10px;
    border: 1px solid rgb(189, 189, 189);
}

.expandable:hover {
    box-shadow: 0 6px 20px rgba(0,0,0,0.18);
}

/* ICON */
.icon {
    width: 26px;
    height: 26px;
    margin-right: 14px;
    position: relative;
    transition: transform 0.4s ease;
    flex-shrink: 0;
}

.icon::before,
.icon::after {
    content: "";
    position: absolute;
    background-color: rgb(52, 186, 156);
    border-radius: 2px;
}

.icon::before {
    width: 100%;
    height: 4px;
    top: 50%;
    left: 0;
    transform: translateY(-50%);
}

.icon::after {
    width: 4px;
    height: 100%;
    left: 50%;
    top: 0;
    transform: translateX(-50%);
}

.expanded .icon {
    transform: rotate(45deg);
}

.label {
    font-weight: 600;
    color: #333;
    font-size: 15px;
}

/* CONTENT */
.content {
    overflow: hidden;
    opacity: 0;
    transition: height 0.4s ease, opacity 0.3s ease;
    margin-bottom: 8px;
    padding: 20px;
    border: 1px solid #fff;
    border-radius: 10px;
    box-shadow: 0 6px 20px rgba(0,0,0,0.18);
    display: none;
}

.expanded + .content {
    display: block;
    opacity: 1;
    margin-top: 10px;
}

.content p {
    margin: 0;
    font-size: 14px;
    line-height: 1.5;
}

.short {
    font-weight: bold;
    text-align: center;
}

.text_title {
    text-align: center;
    background: none;
    box-shadow: none;
    padding:0;
    border:none;
}

.text_title h1 {
    font-family: 'Times New Roman', serif;
    font-weight: 100;
    font-size: 45px;
    margin: 10px 0px;
}

.credits {
    font-weight: bold;
    margin: 0;
}

.question-container h2 {
    font-size: 1.8rem;
    font-family: 'Oswald', sans-serif;
}

.content_ub p, .content_ub li, .content_ub ul {
    margin: 0;
    font-family: 'Times New Roman', serif;
}

.katex {
  font: normal 1em "Times New Roman", serif !important;
}

.yt_video {
    text-align: center;
    width: 100%;
}

.yt_video iframe {
    max-width: 100%;
}

.back-link {
    margin-left: 10px;
    font-size: 13px;
    font-weight: 600;
    color: rgb(52, 186, 156);
    text-decoration: none;
    padding: 6px 10px;
    border-radius: 8px;
    transition: background 0.2s ease;
}

.back-link:hover {
    background: rgba(52, 186, 156, 0.12);
}