body {
    background: #060610;
    font-family: Arial, sans-serif;
}

.section { 
    background-color: #000000c5;
    margin-bottom: 0px;
    margin-top: 0px;
}


.section { 
    padding: 40px 20px;
    text-align: center;
}

.section h2 {
    font-size: 36px;
    margin-bottom: 20px;
}

.section p {
    font-size: 18px;
    margin-bottom: 20px;
}



#subjects {
    padding: 50px;
    
}

#subjects h2 {
    text-align: center;
    margin-bottom: 50px;
    color: #fff;
}
#subjects .cards {
    display: flex;
    flex-wrap: wrap;
    gap: 20px;
    justify-content: center;
}

#subjects .card {
    display: block;
    width: 220px;
    padding: 15px;
    border: 1px solid #0f0000;
    border-radius: 8px;
    text-align: center;
    background-color: #fff;
    text-decoration: none; 
    color: inherit; 
    transition: box-shadow 0.3s, transform 0.3s;
}

#subjects .card:hover {
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    transform: translateY(-5px); 
}

#subjects .card img {
    width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: 10px;
}

#subjects .card h3 {
    font-size: 18px;
    margin: 10px 0;
}

#subjects .card p {
    font-size: 14px;
    margin-bottom: 0;
}

.cards {
    display: flex;
    justify-content: center;
    gap: 20px;
    flex-wrap: wrap;
}

.card {
    background: white;
    padding: 20px;
    width: 300px;
    box-shadow: 0 2px 5px rgba(0, 0, 0, 0.1);
    border-radius: 8px;
    text-align: left;
    text-decoration: none;
    color: inherit;
    transition: box-shadow 0.3s, transform 0.3s;
}

.card:hover {
    box-shadow: 0 4px 10px rgba(0, 0, 0, 0.2);
    transform: translateY(-5px);
}

.card img {
    width: 100%;
    height: auto;
    border-radius: 8px;
    margin-bottom: 15px;
}

.card h3 {
    font-size: 24px;
    margin-bottom: 10px;
}

.card p {
    font-size: 16px;
}


.navbar {
    position: sticky;
    top: 0;
    display: flex;
    justify-content: space-between;
    align-items: center;
    background-color: #fff;
    padding: 4px;
    margin-top: 0; /* Remove initial margin to stick at absolute top; adjust if needed */
    z-index: 1000; /* Ensure it's above other content */
}

.navbar .logo {
    display: flex;
    align-items: center;
    color: #003366;
    font-size: 24px;
}

.navbar .logo img.logo-img {
    height: 50px; 
    width: auto;
    margin-right: 10px;
}

.navbar ul.nav-links {
    display: flex;
    gap: 25px;
    list-style: none;
}

.navbar ul.nav-links li a {
    text-decoration: none;
    color: #003366;
    font-weight: 500;
    position: relative;
    font-size: 18px;
}

.navbar ul.nav-links li a::after {
    content: '';
    position: absolute;
    left: 0;
    bottom: -5px;
    width: 0;
    height: 2px;
    background: #003366;
    transition: 0.3s;
}

.navbar ul.nav-links li a:hover::after {
    width: 100%;
}


.search-container {
    display: flex;
    align-items: center;
}

.search-input {
    padding: 8px 15px;
    border-radius: 20px;
    border: 1px solid #003087;
    font-size: 16px;
    width: 200px;
    transition: border-color 0.3s;
}

.search-input:focus {
    border-color: #d32f2f;
    outline: none;
}

.search-button {
    background-color: #003087;
    border: none;
    color: white;
    padding: 8px 12px;
    cursor: pointer;
    border-radius: 20px;
    margin-left: 5px;
    transition: background-color 0.3s;
}

.search-button:hover,
.search-button:focus {
    background-color: #d32f2f;
    outline: none;
}

.menu-toggle {
    display: none; /* hide on desktop */
    font-size: 28px;
    cursor: pointer;
    color: #003366;
}

/* ===== FOOTER ===== */
.footer {
    background-color: #001F3F;
    color: #fff;
    padding: 40px 20px 0 20px;
    border-top: 3px solid black;
}

.footer-container {
    display: flex;
    flex-wrap: wrap;
    justify-content: space-between;
    gap: 30px;
    margin-bottom: 30px;
}

.footer-col {
    flex: 1;
    min-width: 200px;
}

.footer-col h4 {
    margin-bottom: 15px;
    font-weight: bold;
}

.footer-col ul {
    list-style: none;
    padding: 0;
}

.footer-col ul li {
    margin-bottom: 10px;
}

.footer-col ul li a,
.footer a {
    color: white;
    text-decoration: none;
    transition: 0.3s;
}

.footer-col ul li a:hover,
.footer a:hover {
    text-decoration: underline;
}

.footer p {
    font-size: 14px;
    opacity: 0.9;
    margin: 4px 0;
}

.social-icons {
    display: flex;
    gap: 12px;
    margin-top: 10px;
}

.social-icons a {
    color: white;
    font-size: 22px;
    text-decoration: none;
    transition: transform 0.3s;
}

.social-icons a:hover {
    transform: scale(1.2);
}

.designer {
    margin-top: 15px;
    opacity: 0.9;
    font-size: 14px;
}

.footer-bottom {
    text-align: center;
    padding: 15px 0;
    border-top: 1px solid rgba(255, 255, 255, 0.3);
    font-size: 14px;
    margin-top: 10px;
}

.footer-bottom p {
    margin: 0;
    opacity: 0.9;
}

/* ===== FOOTER MOBILE ===== */
@media (max-width: 768px) {
    .footer-container {
        flex-direction: column;
        gap: 20px;
    }

    .footer-col {
        min-width: unset;
        width: 100%;
        text-align: center;
    }

    .social-icons {
        justify-content: center;
    }
}

@media (max-width: 768px) {
    .navbar {
        background-color: #d32f2f; /* solid mobile navbar */
        padding: 10px 20px;
        position: sticky;
        top: 0;
        z-index: 1000;
        box-shadow: 0 4px 6px rgba(0,0,0,0.1);
    }

    .navbar .logo {
        display: none; /* hide logo on mobile */
    }

    .menu-toggle {
        display: block;
        font-size: 28px;
        cursor: pointer;
        color: #fff;
    }

    .navbar ul.nav-links {
        display: none;
        flex-direction: column;
        position: absolute;
        top: 60px;
        left: 0;
        width: 100%;
        background-color: #d32f2f; /* solid red background */
        padding: 0;
        margin: 0;
        z-index: 999;
        list-style: none;
        border-top: 1px solid #b72b27; /* slightly darker top border */
    }

    .navbar ul.nav-links.active {
        display: flex;
    }

    .navbar ul.nav-links li {
        width: 100%;
        text-align: center;
        margin: 0;
        border-bottom: 1px solid #b72b27; /* lines between items */
    }

    .navbar ul.nav-links li:last-child {
        border-bottom: none; /* remove last line */
    }

    .navbar ul.nav-links li a {
        display: block;
        padding: 15px 0;
        color: #fff;
        text-decoration: none;
        font-size: 18px;
        font-weight: 500;
    }

    .navbar ul.nav-links li a:hover {
        background-color: #b72b27; /* darker hover */
    }

    .search-container {
        order: 2; /* keep search bar on right */
        width: auto;
    }

    
}

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

/*  PERIODIC TABLE SECTION */
.pt-page {
    background: #060610;
    padding: 24px 16px 40px;
    margin-top: 0;
}

.pt-page .pt-title-block h1 {
    color: #fff;
}

.pt-page .pt-title-block p {
    color: #888;
}

.pt-legend {
    color: #aaa;
}

.pt-header{
  display:flex;
  flex-wrap:wrap;
  gap:16px;
  align-items:flex-start;
  justify-content:space-between;
  margin-bottom:16px;
}
.pt-title-block h1{font-size:26px;font-weight:700;color:#fff}
.pt-title-block p{font-size:13px;color:#888;margin-top:4px}
 
.pt-controls{display:flex;flex-wrap:wrap;gap:10px;align-items:center}
 
.pt-search-wrap{
  display:flex;
  align-items:center;
  gap:8px;
  background:#111128;
  border:1px solid #333;
  border-radius:24px;
  padding:7px 14px;
}
.pt-search-wrap i{color:#888;font-size:13px}
.pt-search-wrap input{
  background:none;border:none;outline:none;
  color:#fff;font-size:13px;width:200px;
}
.pt-search-wrap input::placeholder{color:#555}
 
#pt-filter{
  background:#111128;border:1px solid #333;color:#fff;
  padding:8px 12px;border-radius:24px;font-size:13px;
  outline:none;cursor:pointer;
}
#pt-filter:focus{border-color:#c0392b}
 
.toggle-btn{
  background:#c0392b;border:none;color:#fff;
  padding:8px 18px;border-radius:24px;font-size:13px;
  cursor:pointer;font-weight:600;
  display:flex;align-items:center;gap:7px;
  transition:background 0.2s,transform 0.1s;
}
.toggle-btn:hover{background:#a93226}
.toggle-btn:active{transform:scale(0.97)}
 
/* ===== LEGEND ===== */
.pt-legend{
  display:flex;flex-wrap:wrap;gap:8px 16px;
  margin-bottom:14px;
}
.leg-item{display:flex;align-items:center;gap:5px;font-size:11px;color:#aaa}
.leg-dot{display:inline-block;width:10px;height:10px;border-radius:3px;flex-shrink:0}
 
/* ===== GRID ===== */
#pt-grid-view{display:block}
.pt-grid-scroll{overflow-x:auto;padding-bottom:6px}
 
#pt-grid{
  display:grid;
  grid-template-columns:repeat(18,minmax(52px,1fr));
  gap:3px;
  min-width:960px;
}
 
.el{
  border-radius:7px;
  padding:5px 4px 4px;
  cursor:pointer;
  position:relative;
  transition:transform 0.15s,box-shadow 0.15s,opacity 0.2s;
  min-height:58px;
  display:flex;flex-direction:column;
  align-items:center;justify-content:center;
  border:1px solid rgba(255,255,255,0.07);
  user-select:none;
}
.el:hover{
  transform:scale(1.15);
  box-shadow:0 0 14px rgba(192,57,43,0.7);
  z-index:20;
  border-color:rgba(255,255,255,0.35);
}
.el.dimmed{opacity:0.1;pointer-events:none}
.el.highlighted{
  transform:scale(1.18);
  box-shadow:0 0 18px rgba(255,215,0,0.85);
  border-color:#ffd700;
  z-index:20;
}
.el-spacer{min-height:58px;background:transparent;border:none;pointer-events:none}
 
.el-num{font-size:9px;color:rgba(255,255,255,0.55);align-self:flex-start;line-height:1}
.el-sym{font-size:18px;font-weight:700;color:#fff;line-height:1.15}
.el-name{font-size:8px;color:rgba(255,255,255,0.6);text-align:center;line-height:1.2;margin-top:2px;word-break:break-word}
 
.pt-series-label{
  display:flex;gap:30px;
  margin-top:8px;
  font-size:12px;color:#666;
  padding-left:4px;
}
 
/* ===== 3D VIEW ===== */
#pt-3d-view{
  display:none;
  width:100%;
  height:560px;
  position:relative;
  border-radius:10px;
  overflow:hidden;
  background:#000010;
  border:1px solid #222;
}
#three-canvas{width:100%;height:100%;display:block;cursor:grab}
#three-canvas:active{cursor:grabbing}
 
.hint-3d{
  position:absolute;bottom:14px;left:50%;
  transform:translateX(-50%);
  font-size:11px;color:#555;
  background:rgba(0,0,0,0.5);
  padding:5px 14px;border-radius:20px;
  pointer-events:none;white-space:nowrap;
}
 
/* ===== MODAL ===== */
#pt-modal-overlay{
  display:none;
  position:fixed;
  inset:0;
  background:rgba(0,0,0,0.8);
  z-index:500;
  align-items:center;
  justify-content:center;
  padding:16px;
}
#pt-modal-overlay.open{display:flex}
 
#pt-modal{
  background:#0f0f23;
  border-radius:14px;
  padding:28px;
  width:100%;
  max-width:380px;
  border:1px solid #2a2a4a;
  position:relative;
  animation:modalIn 0.2s ease;
}
@keyframes modalIn{from{opacity:0;transform:scale(0.92)}to{opacity:1;transform:scale(1)}}
 
#pt-modal-close{
  position:absolute;top:14px;right:14px;
  background:rgba(255,255,255,0.08);
  border:none;color:#fff;
  width:30px;height:30px;border-radius:50%;
  cursor:pointer;font-size:13px;
  display:flex;align-items:center;justify-content:center;
  transition:background 0.2s;
}
#pt-modal-close:hover{background:rgba(192,57,43,0.6)}
 
.modal-top{
  display:flex;align-items:center;gap:20px;
  margin-bottom:20px;
  padding-bottom:20px;
  border-bottom:1px solid #1e1e3a;
}
.modal-sym-wrap {
    width: 80px;
    height: 80px;
    border-radius: 12px;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    background: #fff;          
    border: 3px solid #ccc;
}

#md-num-top {
    font-size: 11px;
    color: #999;
    line-height: 1;
}

#md-sym {
    font-size: 40px;
    font-weight: 700;
    line-height: 1.1;
    
}

#md-mass-top {
    font-size: 10px;
    color: #999;
}
 
.modal-info h2{font-size:22px;font-weight:700;color:#fff;margin-bottom:8px}
#md-cat-badge{
  display:inline-block;
  font-size:11px;padding:3px 10px;
  border-radius:20px;
  font-weight:600;
  color:#fff;
}
 
.modal-grid{
  display:grid;
  grid-template-columns:1fr 1fr;
  gap:8px;
  margin-bottom:14px;
}
.modal-row{
  background:#0a0a1e;
  border-radius:8px;
  padding:10px 12px;
  border:1px solid #1e1e3a;
}
.modal-label{font-size:10px;color:#666;margin-bottom:3px;text-transform:uppercase;letter-spacing:0.5px}
.modal-val{font-size:15px;color:#fff;font-weight:600}
 
.modal-fact{
  background:#0a0a1e;
  border-radius:8px;
  padding:12px;
  font-size:13px;
  color:#aaa;
  line-height:1.6;
  border-left:3px solid #c0392b;
  border-radius:0 8px 8px 0;
}


@media (max-width: 768px) {
    .cards {
        display: grid; 
        grid-template-columns: repeat(2, 1fr); /* 👈 2 cards per row */
        gap: 15px; 
        padding: 0 10px;
    }

    .card {
        width: 100%; 
        margin: 0; 
        padding: 15px;
    }

    .card h2 {
        font-size: 22px; 
        margin-bottom: 15px; 
    }

    .card h3 {
        font-size: 16px; 
        text-align: center;
    }

    .card p {
        font-size: 13px; 
    }
}

@media (max-width: 768px) {
 
    
    /* Section */
    .section {
        padding: 40px 16px;
        min-height: calc(100vh - 58px);
        justify-content: flex-start;
        padding-top: 50px;
    }
 
    .section h2 {
        font-size: 26px;
        margin-bottom: 28px;
    }
 
    /* Grade cards — 2 columns, full width */
    .cards {
        grid-template-columns: repeat(2, 1fr);
        gap: 14px;
        width: 100%;
        max-width: 420px;
    }
 
    .card img {
        height: 120px;
    }
 
    .card h3 {
        font-size: 16px;
        padding: 12px 8px;
    }
 
    /* Footer */
    .footer-container {
        flex-direction: column;
        gap: 24px;
    }
 
    .footer-col {
        min-width: unset;
        width: 100%;
        text-align: center;
    }
 
    .social-icons {
        justify-content: center;
    }
}

@media (max-width: 425px) {
    .cards {
        grid-template-columns: repeat(2, 1fr) !important;
        gap: 10px;
        width: 100%;
        max-width: 100%;
        padding: 0 10px;
    }

    .card {
        min-width: 0 !important;
        width: 100% !important;
    }

    .card img {
        height: 100px;
    }

    .card h3 {
        font-size: 14px;
        padding: 10px 6px;
    }
}

.whatsapp-float{position:fixed;bottom:22px;right:22px;background:#25D366;color:white;width:54px;height:54px;border-radius:50%;display:flex;align-items:center;justify-content:center;font-size:26px;z-index:999;box-shadow:0 4px 14px rgba(0,0,0,0.25);text-decoration:none;transition:transform 0.3s}
.whatsapp-float:hover{transform:scale(1.1)}