/* =====================
   GENERAL
===================== */

body {

    margin: 0;
    padding: 20px;

    background-color: #a8d5a2;

    background-image: url("clouds.png");
    background-size: cover;
    background-position: center;
    background-repeat: no-repeat;
    background-attachment: fixed;

    font-family: "Trebuchet MS", Verdana, sans-serif;

    color: black;
}

* {
    box-sizing: border-box;
}

/* =====================
   SITE WRAPPER
===================== */

#container {
    max-width: 1000px;
    margin: auto;
}

/* =====================
   HEADER
===================== */

#header {

    text-align: center;

    background: rgba(212,208,200,0.92);

    border-top: 3px solid white;
    border-left: 3px solid white;
    border-right: 3px solid #808080;
    border-bottom: 3px solid #808080;

    padding: 25px;
}

#header h1 {
    margin: 0;
    color: #000080;
}

#header p {
    margin-top: 10px;
}

/* =====================
   NAVBAR
===================== */

#navbar {

    margin-top: 10px;
    margin-bottom: 10px;

    background: rgba(212,208,200,0.95);

    border-top: 3px solid white;
    border-left: 3px solid white;
    border-right: 3px solid #808080;
    border-bottom: 3px solid #808080;
}

#navbar ul {

    list-style: none;
    margin: 0;
    padding: 10px;

    display: flex;
    justify-content: space-around;
    flex-wrap: wrap;
}

#navbar a {

    text-decoration: none;

    color: black;
    font-weight: bold;

    background: #d4d0c8;

    border-top: 2px solid white;
    border-left: 2px solid white;
    border-right: 2px solid #808080;
    border-bottom: 2px solid #808080;

    padding: 6px 14px;

    display: inline-block;
}

#navbar a:hover {

    background: #000080;
    color: white;
}

/* =====================
   FLEX LAYOUT
===================== */

#flex {

    display: flex;
    gap: 15px;
}

#leftSidebar {
    width: 250px;
}

main {
    flex: 1;
}

/* =====================
   WINDOWS
===================== */

.window {

    background: rgba(212,208,200,0.92);

    border-top: 3px solid white;
    border-left: 3px solid white;
    border-right: 3px solid #808080;
    border-bottom: 3px solid #808080;

    margin-bottom: 15px;

    backdrop-filter: blur(2px);
}

.titleBar {

    background: #000080;

    color: white;

    font-weight: bold;

    padding: 6px 10px;
}

.content {
    padding: 15px;
}

.content ul {
    padding-left: 20px;
}

/* =====================
   HEADINGS
===================== */

h2 {
    color: #000080;
}

/* =====================
   LINKS
===================== */

a {
    color: #000080;
}

a:hover {
    color: #cc0000;
}

/* =====================
   FOOTER
===================== */

footer {

    background: rgba(212,208,200,0.95);

    border-top: 3px solid white;
    border-left: 3px solid white;
    border-right: 3px solid #808080;
    border-bottom: 3px solid #808080;

    text-align: center;

    margin-top: 10px;

    padding: 10px;
}

/* =====================
   SCROLLBAR
===================== */

::-webkit-scrollbar {
    width: 14px;
}

::-webkit-scrollbar-track {
    background: #d4d0c8;
}

::-webkit-scrollbar-thumb {
    background: #808080;
    border: 2px solid #d4d0c8;
}

/* ====================
   LETTER ROOM
==================== */

label{
    display:block;
    font-weight:bold;
    margin-bottom:5px;
}

select,
textarea,
input{
    width:100%;
    padding:8px;
    font-family:inherit;
}

button{

    margin-right:10px;

    padding:8px 16px;

    cursor:pointer;

    background:#d4d0c8;

    border-top:2px solid white;
    border-left:2px solid white;
    border-right:2px solid #808080;
    border-bottom:2px solid #808080;
}

button:hover{
    background:#000080;
    color:white;
}

#envelopePreview{

    width:250px;
    height:150px;

    margin:auto;

    background:white;

    border:2px solid #808080;

    display:flex;
    align-items:center;
    justify-content:center;

    font-size:48px;
}

#letterPreview{

    min-height:300px;

    padding:20px;

    background:white;

    border:1px solid #808080;

    white-space:pre-wrap;

    line-height:1.6;
}

 /* ENVELOPE */
 
#envelopeContainer{
  
    width:300px;
    height:220px;

    margin:20px auto;

    position:relative;

    cursor:pointer;
}

#envelopeBody{

    position:absolute;

    bottom:0;
    left:0;

    width:300px;
    height:150px;

    background:white;

    border:2px solid #888;

    z-index:1;
}

/* bottom triangle */

#envelopeBody::before{

    content:"";

    position:absolute;

    width:0;
    height:0;

    border-left:150px solid transparent;
    border-right:150px solid transparent;
    border-top:90px solid #eeeeee;

    bottom:0;
    left:0;

    z-index:2;
}

/* flap */

#envelopeFlap{

    position:absolute;

    top:0;
    left:0;

    width:0;
    height:0;

    border-left:150px solid transparent;
    border-right:150px solid transparent;
    border-bottom:90px solid #dcdcdc;

    transform-origin:top center;

    transition:0.6s;

    z-index:4;
}

/* hidden letter */

#secretLetter{

    position:absolute;

    left:20px;
    right:20px;

    top:20px;

    height:100px;

    background:white;

    border:1px solid #bbb;

    padding:10px;

    overflow:auto;

    transition:0.6s;

    z-index:3;
}

/* OPEN */

#envelopeContainer.open #envelopeFlap{

    transform:rotateX(180deg);
}

#envelopeContainer.open #secretLetter{

    transform:translateY(-60px);

    height:150px;
}

/* =====================
   MOBILE
===================== */

@media (max-width: 850px) {

    #flex {
        flex-wrap: wrap;
    }

    #leftSidebar {
        width: 100%;
    }

    main {
        width: 100%;
    }

}

#logo{
    width:300px;
    height:auto;

    display:block;
    margin:auto;
}
#envelopeContainer{

    width:300px;
    height:220px;

    margin:auto;

    position:relative;

    cursor:pointer;
}

#envelopeBody{

    position:absolute;

    bottom:0;

    width:100%;
    height:160px;

    background:white;

    border:2px solid #808080;

    overflow:hidden;
}

#envelopeFlap{

    position:absolute;

    top:40px;
    left:0;

    width:0;
    height:0;

    border-left:150px solid transparent;
    border-right:150px solid transparent;
    border-top:100px solid #d4d0c8;

    transform-origin:top;

    transition:0.6s;
    z-index:3;
}

#secretLetter{

    position:absolute;

    left:20px;
    right:20px;
    bottom:20px;

    height:120px;

    background:white;

    border:1px solid #ccc;

    padding:10px;

    overflow:auto;

    transition:0.6s;
}

#envelopeContainer.open #envelopeFlap{

    transform:rotateX(180deg);
}

#envelopeContainer.open #secretLetter{

    transform:translateY(-70px);

    height:180px;
}
.courseCard{

    background: rgba(255,255,255,0.6);

    padding:15px;

    margin-bottom:20px;

    border-top:2px solid white;
    border-left:2px solid white;
    border-right:2px solid #808080;
    border-bottom:2px solid #808080;
}

.courseCard h3{

    margin-top:0;

    color:#000080;
}
#calendar{

    text-align:center;

    font-size:14px;
}

.calendarHeader{

    font-weight:bold;

    margin-bottom:8px;

    color:#000080;
}

.calendarGrid{

    display:grid;

    grid-template-columns:repeat(7,1fr);

    gap:2px;
}

.calendarDayName{

    font-weight:bold;

    font-size:12px;
}

.calendarCell{

    padding:4px;
}

.today{

    background:#000080;

    color:white;

    border-radius:4px;

    font-weight:bold;
}