:root {
    --background-color: rgb(46, 44, 46);
    --navbar-color: rgb(52, 45, 53, 0.0);
    --footer-background-color: var(--navbar-color);
    --footer-text-color: rgb(145, 128, 128);
    --title-color: #d6cdcd;
    --button-bg-color: #505050;
    --button-hover-bg-color: #404040;
    --button-border-color: #404040;
    --button-hover-border-color: #303030;
    --input-bg-color: rgba(255, 255, 255, 0.5);
    --input-text-color: #d6cdcd;
    --alert-color: var(--input-text-color);
    --toggle-color: #45586d;
    --link-color: var(--title-color);
    --link-hover-color: var(--title-color);
    --modal-background-color: var(--background-color);
    --modal-text-color: var(--title-color);
}

#particles-js {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background-color: var(--background-color);
    background-image: url("");
    background-repeat: no-repeat;
    background-size: cover;
    background-position: 50% 50%;
    z-index: -1;
}

body {
    margin: 0;
    padding: 0;
    height: 100vh;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    color: var(--title-color);
    font-family: 'Georgia', serif;
    -webkit-background-size: cover;
    -moz-background-size: cover;
    -o-background-size: cover;
    background-size: cover;
}

input[type="text"], input[type="email"], input[type="password"] {
    background-color: rgba(10, 9, 9, 0.5);
    border: 1px solid #100f0f;
    color: white;
    border-radius: 4px;
    padding: 10px;
}

textarea {
    background-color:transparent;  
    background:  transparent;
    resize: vertical;
    overflow-y: auto;
}

.modal-content {
    background-color: var(--modal-background-color);
    color: var(--modal-background-color);
    z-index: 1050; 
}

.modal-header .close {
    color: var(--modal-text-color);
}

body, h1, h2, h3, p, a {
    font-family: 'Georgia', serif;
    text-align: center;
}

table {
    margin-top: 20px;
    color: var(--title-color);
}

thead {
    color: var(--title-color);
}

tbody {
    color: var(--title-color);
}

.footer {
    background-color: var(--footer-background-color);
    color: var(--footer-text-color);
    padding: 10px;
    text-align: center;
    margin-top: 20px;
    position: relative;
    bottom: 0;
    width: 100%;
}

.navbar {
    margin-bottom: 20px;
    background-color: var(--navbar-color);
}

a.nav-link {
    color: var(--link-color);
    text-decoration: none;
}

a.nav-link:hover {
    color: var(--link-hover-color);
}

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

.btn-center {
    display: flex;
    justify-content: center;
}

.footer a {
    color: var(--link-color);
    text-decoration: none;
}

.footer a:hover {
    color: var(--link-hover-color);
}

textarea {
    background-color: #1e0606 ;
    border: 1px solid #ccc;
    resize: vertical;
    overflow-y: auto;
}

.btn-primary {
    background-color: var(--button-bg-color);
    border-color: var(--button-border-color);
    margin-bottom: 20px;
}

.btn-primary:hover {
    background-color: var(--button-hover-bg-color);
    border-color: var(--button-hover-border-color);
}

h1, h2 {
    color: var(--title-color);
    padding-top: 20px;
}

.table td, .table th {
    text-align: left;
    vertical-align: middle;
}

.text-center {
    margin-top: 20px;
}

.btn-danger {
    width: 100px;
}

.btn-info {
    width: 100px;
    height: 50;
}

.form-text.text-muted {
    color: var(--alert-color) !important;
}

.btn-toggle {
    border: none;
    background: none;
    color: var(--toggle-color);
    cursor: pointer;
}

.content-hidden {
    display: none;
}

.container {
    flex: 1;
}

.modal-content {
    background-color: var(--modal-background-color);
    color: var(--modal-text-color);
}

.modal-header .close {
    color: var(--modal-text-color);
}

.flip-card {
    background-color: transparent;
    width: 100%;
    height: 200px;
    perspective: 1000px;
}

.flip-card-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
}

.flip-card:hover .flip-card-inner {
    transform: rotateY(180deg);
}

.flip-card-front,
.flip-card-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    padding: 20px;
}

.flip-card-front {
    background-color: #313840;
    color: white;
}

.flip-card-back {
    background-color: #8fa2b5;
    color: black;
    transform: rotateY(180deg);
}


.sidebar {
    position: fixed;
    top: 0;
    left: -300px;
    width: 300px;
    height: 100%;
    background-color: #343a40;
    color: white;
    transition: 0.3s;
    z-index: 1000;
}

.sidebar.active {
    left: 0;
}

.sidebar-content {
    padding: 20px;
}

.flashcards {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-around;
}

.flashcard {
    background-color: white;
    width: 900px;
    height: 900px;
    margin: 20px;
    perspective: 1000px;
}

.flashcard-inner {
    position: relative;
    width: 100%;
    height: 100%;
    text-align: center;
    transition: transform 0.8s;
    transform-style: preserve-3d;
    box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.2);
    border-radius: 10px;
}

.flashcard:hover .flashcard-inner {
    transform: rotateY(180deg);
}

.flashcard-front, .flashcard-back {
    position: absolute;
    width: 100%;
    height: 100%;
    -webkit-backface-visibility: hidden;
    backface-visibility: hidden;
    border-radius: 10px;
}

.flashcard-front {
    background-color: #091d2b;
    color: white;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 24px;
}

.flashcard-back {
    background-color: rgb(207, 214, 234);
    color: black;
    transform: rotateY(180deg);
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 20px;
    box-sizing: border-box;
    text-align: justify;
}

.col-lg-7 {
    background-color: rgba(68, 68, 68, 0.85); 
    padding: 20px;
    border-radius: 10px;
    color: white;
}

.col-lg-7 h5 {
    font-size: 1.2rem;
    margin-top: 15px;
    color: #f8f9fa;
}

.col-lg-7 p {
    font-size: 1rem;
    line-height: 1.6;
}