/* ===========================
        RESET
        =========================== */

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

        html{
            scroll-behavior:smooth;
        }

        body{
            font-family:Arial, Helvetica, sans-serif;
            background:#def7ff;
            min-height:100vh;
            overflow-x:hidden;
            color:#222;
        }

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

        nav{
            width:100%;
            padding:0.75rem 2rem;
            display:flex;
            justify-content:space-between;
            align-items:center;
            background:#fff;
            border-bottom:1px solid rgba(0,0,0,.08);
            box-shadow:0 2px 8px rgba(0,0,0,.08);
            position:sticky;
            top:0;
            z-index:1000;
        }

        .brand{
            display:flex;
            align-items:center;
            gap:12px;
        }

        .brand img{
            width:55px;
            height:55px;
            display:block;
        }

        .brand h1{
            font-family:'Orbitron',sans-serif;
            font-size:clamp(1.4rem,2vw,1.8rem);
            letter-spacing:2px;
            margin:0;
        }

        .mech a{
            text-decoration:none;
            color:#012043;
        }

        .circuits a{
            text-decoration:none;
            color:#0057d9;
        }

        nav ul{
            display:flex;
            align-items:center;
            gap:2rem;
            list-style:none;
        }

        nav ul li a{
            text-decoration:none;
            color:#003db8;
            font-size:1.05rem;
            transition:.3s;
        }

        nav ul li a:hover{
            color:#00bcd4;
        }

        /* ===========================
        HAMBURGER MENU
        =========================== */

        .hamburger{
            display:none;
            flex-direction:column;
            gap:5px;
            cursor:pointer;
        }

        .hamburger span{
            width:28px;
            height:3px;
            background:#003366;
            border-radius:3px;
            transition:.3s;
        }

        /* ===========================
        CONTACT & FEEDBACK POPUPS
        =========================== */

        .contact-menu,
        .feedback-menu{
            position:relative;
        }

        .contact-box,
        .feedback-box{
            display:none;
            position:absolute;
            top:42px;
            right:0;
            width:320px;
            background:#fff;
            color:#012043;
            padding:18px;
            border-radius:12px;
            box-shadow:0 8px 25px rgba(0,0,0,.25);
            z-index:9999;
            animation:popup .2s ease;
        }

        @keyframes popup{
            from{
                opacity:0;
                transform:translateY(-8px);
            }
            to{
                opacity:1;
                transform:translateY(0);
            }
        }

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

        @media (max-width:600px){

            nav{
                display:flex;
                justify-content:space-between;
                align-items:center;
                flex-wrap:wrap;
                padding:15px 20px;
            }

            .brand{
                display:flex;
                align-items:center;
                gap:10px;
                flex:1;
            }

            .brand img{
                width:45px;
                height:45px;
            }

            .brand h1{
                font-size:28px;
                margin:0;
            }

            .hamburger{
                display:flex;
                flex-direction:column;
                gap:5px;
                cursor:pointer;
                margin-left:auto;
            }

            .hamburger span{
                width:28px;
                height:3px;
                background:#003366;
                border-radius:3px;
            }

            #nav-links{
                display:none;
                width:100%;
                flex-direction:column;
                margin-top:10px;
                gap:0;
                padding:0;
            }

            #nav-links.active{
                display:flex;
            }

            #nav-links li{
                width:100%;
                margin:0;
                padding:0;
                list-style:none;
                line-height:1;
            }

            #nav-links li a{
                display:block;
                padding:10px 15px;
                margin:0;
                text-align:center;
                line-height:1.2;
            }

            .contact-box,
            .feedback-box{
                position:fixed;
                top:90px;
                left:50%;
                right:auto;
                transform:translateX(-50%);
                width:320px;
                max-width:90%;
            }
        }

        /* ===========================
        EXTRA SMALL PHONES
        =========================== */

        @media (max-width:380px){

            nav{
                padding:.8rem;
            }

            .brand h1{
                font-size:1.2rem;
            }
        }


/* ===========================
   BEAM SIMULATOR
   =========================== */

main {
    width: 100%;
    max-width: 1400px;
    margin: 0 auto;
    padding: 35px 25px 60px;
}

.simulator-container {
    display: grid;
    grid-template-columns: 380px 1fr;
    gap: 25px;
    align-items: start;
}

/* ===========================
   WHITE CARDS
   =========================== */

.simulator-card {
    background: #fff;
    border-radius: 16px;
    padding: 25px;
    box-shadow: 0 4px 18px rgba(0,0,0,.08);
    border: 1px solid rgba(0,0,0,.05);
}

/* ===========================
   BOTH SIMULATOR CARDS
   =========================== */

.input-card,
.visualization-card {
    height: 600px;
    min-height: 600px;
    overflow-y: auto;
    overflow-x: hidden;
    box-sizing: border-box;
}

/* HEADINGS */

.simulator-card h2 {
    color: #012043;
    font-size: 1.25rem;
    margin-bottom: 20px;
}

/* ===========================
   INPUT SECTIONS
   =========================== */

.input-section {
    margin-bottom: 25px;
}

.input-section h3 {
    font-size: 1rem;
    color: #0057d9;
    margin-bottom: 12px;
    padding-bottom: 8px;
    border-bottom: 1px solid #e5e5e5;
}

/* INPUT GROUP */

.input-group {
    margin-bottom: 15px;
}

.input-group label {
    display: block;
    font-size: .9rem;
    font-weight: 600;
    margin-bottom: 6px;
    color: #333;
}

.input-group input,
.input-group select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #d5d5d5;
    border-radius: 8px;
    font-size: .95rem;
    outline: none;
    background: #fff;
    transition: .2s;
}

.input-group input:focus,
.input-group select:focus {
    border-color: #0057d9;
    box-shadow: 0 0 0 3px rgba(0,87,217,.1);
}

.section-image {
    display: block;
    width: 250px;
    height: 250px;
    object-fit: contain;
    margin: 15px auto;
}

/* ===========================
   BEAM DISPLAY
   =========================== */

.beam-display {
    width: 100%;
    min-height: 220px;
    border: 1px solid #e5e5e5;
    border-radius: 12px;
    background: #fafafa;

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

    margin-bottom: 25px;
}

/* ===========================
   RESULTS
   =========================== */

.results-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 15px;
}

.result-box {
    background: #f7fbff;
    border: 1px solid #dceeff;
    border-radius: 10px;
    padding: 15px;
}

.result-label {
    font-size: .8rem;
    color: #666;
    margin-bottom: 5px;
}

.result-value {
    font-size: 1.15rem;
    font-weight: 700;
    color: #012043;
}

/* ===========================
   DIAGRAMS
   =========================== */

.diagram {
    width: 100%;
    height: 250px;
    margin-top: 20px;

    border-radius: 12px;
    border: 1px solid #e5e5e5;
    background: #fff;
}

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

@media (max-width: 900px) {

    .simulator-container {
        grid-template-columns: 1fr;
    }

    .input-card,
    .visualization-card {
        min-height: auto;
    }
}

@media (max-width: 600px) {

    main {
        padding: 20px 15px 40px;
    }

    .simulator-container {
        gap: 18px;
    }

    .simulator-card {
        padding: 20px;
        border-radius: 14px;
    }

    .results-grid {
        grid-template-columns: 1fr;
    }
}
/* ===========================
   LOADS
   =========================== */

.load-item {
    width: 100%;
    border: 1px solid #dce3ea;
    border-radius: 10px;
    overflow: hidden;
    margin-bottom: 12px;
    background: #fff;
}


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

.load-header {
    width: 100%;
    height: 48px;

    display: flex;
    align-items: center;

    background: #f7fbff;
}


/* ===========================
   LOAD TOGGLE
   =========================== */

.load-toggle {
    flex: 1;
    height: 48px;

    padding: 0 15px;

    border: none;
    background: transparent;

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

    cursor: pointer;

    font-size: .95rem;
    font-weight: 600;

    color: #012043;

    text-align: left;
}

.load-toggle:hover {
    background: #eef7ff;
}


/* ===========================
   ARROW
   =========================== */

.load-arrow {
    font-size: .75rem;
    color: #0057d9;

    transition: transform .2s;
}

.load-item.active .load-arrow {
    transform: rotate(180deg);
}


/* ===========================
   DELETE BUTTON
   =========================== */

.delete-load {
    width: 48px;
    height: 48px;

    flex-shrink: 0;

    border: none;
    background: transparent;

    color: #d93025;

    font-size: 1.4rem;

    cursor: pointer;

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

    transition: .2s;
}

.delete-load:hover {
    background: #fff0f0;
    color: #b71c1c;
}


/* ===========================
   LOAD CONTENT
   =========================== */

.load-content {
    display: none;

    padding: 18px 15px 5px;

    border-top: 1px solid #e5e5e5;
}

.load-item.active .load-content {
    display: block;
}


/* ===========================
   ADD LOAD BUTTON
   =========================== */

.add-load-btn {
    width: 100%;
    padding: 11px;

    border: 1px dashed #0057d9;
    border-radius: 8px;

    background: #f7fbff;
    color: #0057d9;

    font-size: .9rem;
    font-weight: 600;

    cursor: pointer;
    transition: .2s;
}

.add-load-btn:hover {
    background: #eef7ff;
}

.beam-display {
    width: 100%;
    display: flex;
    justify-content: center;
    align-items: flex-start;
    overflow-x: auto;
    padding: 10px 0;
}

.beam-svg {
    display: block;
    width: 100%;
    max-width: 950px;
    height: auto;
}

/* ===========================
   TOOL DESCRIPTION
   =========================== */

.tool-description {
    margin-top: 30px;
    padding-top: 10px;
}

.tool-description h2 {
    color: #012043;
    font-size: 1.25rem;
    margin-bottom: 18px;
}

.tool-description p {
    font-size: .95rem;
    line-height: 1.7;
    color: #444;
    margin-bottom: 15px;
}