* {
   box-sizing: border-box;
    margin: 0;
}

body {
    font-family: "Segoe UI", Tahoma, Geneva, Verdana, sans-serif;
}

.drawing-area {
    display: flex; 
    position: absolute; 
    top: 0; 
    flex-wrap: wrap; 
    justify-content: flex-start;
    align-items: flex-start; 
    background-color: #333; 
    width: 100%; 
    height: 100vh; 
    z-index: -1; 
}

    .drawing-area .click-instruction {
        position: absolute;
        top: 50%;
        left: 50%;
        transform: translate(-50%, -50%);
        color: #fff;
        pointer-events: none;
        z-index: -10;
    }

.block {
    position: absolute;
    width: 50px;
    height: 50px;
    border: 5px solid rgb(163, 211, 208);
    border-radius: 50%;
    margin-top: -3px; 
    display: flex;
    justify-content: center;
    align-items: center;
    color: #fff; 
    cursor: pointer; 
    z-index: 10;
}

.outline-btn {
    border: 2px solid rgb(102, 216, 159);
    background-color: transparent; 
    border-radius: 4px;
    cursor: pointer;
    outline: none; 
    color: #fff;
    padding: 6px 10px; 
    margin-left: 15px;
    margin-top: 10px;
}

    .outline-btn:disabled {
        border: 2px solid #ea0000;
        cursor: not-allowed;
    }

    #fix-length {
        border: 2px solid rgb(255, 255, 255);
        background-color: transparent; 
        border-radius: 4px; 
        cursor: pointer;
        outline: none;
        color: #fff;
        padding: 6px 10px; 
        margin-left: 15px;
    }

    #fix-length.default {
        border: 2px solid rgb(255, 255, 255);
    }

    #fix-length.selected {
        border: 2px solid rgb(240, 240, 8);
    }

    #fix-length.disabled {
        border: 2px solid #ea0000;
        cursor: not-allowed;
      }
.reset-btn {
    margin-left: 15px;
}

.line {
    height: 5px; 
    background-color: lemonchiffon; 
    position: absolute;
    transform-origin: top left; 
    text-align: center;
    color: #eee;
    line-height: 2rem; 
}

    .line .edge-weight {
        padding: 0 10px;
        width: max-content; 
        margin: auto; 
    }

header {
    width: 100%;
    padding: 20px;
    background-color: #0e2a86;
    text-align: center;
}

    header .title {
        font-size: 2rem; 
        color: #fff;
    }

        header .title a:nth-child(2) {
            width: 40px;
            height: 40px;
            position: absolute;
            right: 10px;
        }

        header .title a {
            text-decoration: none; 
            color: #fff;
            cursor: not-allowed;
        }

a > img {
    width: 100%;
    height: 100%;
}

main h3 {
    padding: 20px;
    font-weight: 1.2rem;
}

main ul > li {
    padding: 0.5rem; 
}

.options {
    margin-top: 20px;
    display: flex;
    justify-content: space-around;
}
    .options input {
        outline: 0;
        padding: 6px;
        width: 100px;
    }

.path {
    position: absolute;
    bottom: 0;
    right: 0;
    height: min-content; 
    color: #fff;
    overflow-x: scroll; 
    width: 40%;
    min-width: 300px; 
    background-color: rgba(146, 146, 146, 0.4);
    transition-duration: 1s;
}

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

@media screen and (max-width: 735px) {
    header .options {
      flex-direction: column;
      align-items: center;
    }
  
    header .options > div {
      margin-top: 10px;
      text-align: center;
    }
  
    .outline-btn,
    #fix-length {
      margin: 10px 10px 5px 0;
    }
  
    .drawing-area .click-instruction {
      font-size: 14px;
    }
  
    .block {
      width: 40px;
      height: 40px;
    }

    #source-node {
        margin-right: 10px;
    }
}