/* maths html css */
/* Chapters Section */
.chapters-container {
    max-width: 700px;
    margin: 30px auto;
    padding: 0 20px;
    display:flex;
    gap: 20px;
    flex-direction:column;
    z-index: 10;
}

.note-card{
    min-height: 140px;
    z-index: 11;
}

/* SUBJECT PAGE NOTE CARDS */

.chapters-container .note-card{
padding:28px 24px;

border-radius:20px;

background:linear-gradient(
145deg,
rgba(255,255,255,0.05),
rgba(255,255,255,0.02)
);

border:1px solid rgba(255,255,255,0.1);

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

gap:10px;

min-height:160px;

transition:all 0.25s ease;
}

.note-card a{
margin-top:6px;
}

.login-btn{
background:rgba(255,255,255,0.08);
color:white;
padding:8px 16px;
border-radius:20px;
text-decoration:none;
font-size:13px;
border:1px solid rgba(255,255,255,0.15);
}

.chapters-container .note-card:hover{

transform:translateY(-5px);

border-color:#38bdf8;

box-shadow:0 0 18px rgba(56,189,248,0.35);

}

.note-actions{
display:flex;
gap:10px;
justify-content:center;
flex-wrap:wrap;
margin-top:10px;
}

.chapters-container h3{
font-size:20px;
margin-bottom:5px;
font-weight:600;
}

.chapters-container p{
opacity:0.65;
font-size:12px;
margin-bottom: 12px;
}

/* Card */
.chapter-card {
    padding: 30px;
    border-radius: 20px;
    transition: 0.3s ease;
    text-align: left;
    border: 1px solid var(--border-color);
}

/* Dark Mode */
body.dark .chapter-card {
    background: rgba(255, 255, 255, 0.04);
}

/* Light Mode */
.chapter-card {
    background: #ffffff;
    border: 1px solid #e2e8f0;
    box-shadow: 0 10px 25px rgba(0, 0, 0, 0.05);
    color: #1e293b;
    transition: all 0.3s ease;
}

body.light-mode .chapter-card button {
    background: #2563eb;
    color: white;
}

body.light-mode .chapter-card button:hover {
    background: #1d4ed8;
}

/* Hover */
.chapter-card:hover {
    transform: translateY(-6px);
}

body.light-mode .chapter-card:hover {
    transform: translateY(-6px);
    box-shadow: 0 12px 30px rgba(0, 0, 0, 0.08);
}

/* Title */
.chapter-card h3 {
    font-size: 18px;
    font-weight: 600;
    margin-bottom: 20px;
}

/* Button */
.view-btn {
    background-color: #ffffff;
    border-radius: 20px;
    border: none;
    cursor: pointer;
    font-weight: 500;
    transition: 0.3s ease;
    display: inline-block;
    padding: 10px 20px;    
    text-decoration: none;
    font-size: 14px;
}

/* Dark Button */
body.dark .view-btn {
    background: linear-gradient(90deg, #4da3ff, #7c5cff);
    color: white;
}
/* Light Button */
body.light-mode .view-btn {
    background: #2563eb;
    color: white;
}
body.light-mode .view-btn:hover {
    background: #1d4ed8;
}

.view-btn:hover {
    opacity: 0.85;
    font-size: 15px;
}
.subject-hero{
max-width:900px;
margin:30px auto;
text-align:center;
padding:40px 20px;
position: relative;
}

.subject-hero::before{
content:"";
position:absolute;
width:400px;
height:400px;
background:radial-gradient(
circle,
rgba(56,189,248,0.08),
transparent 70%
);
top:-70px;
left:50%;
transform:translateX(-50%);
z-index:-1;
pointer-events: none;
}

.subject-hero h2 {
    font-size: 36px;
    font-weight: 600;
    margin-bottom: 10px;
    letter-spacing: 0.5px;
    text-shadow:0 0 20px rgba(56,189,248,0.3);
}

.subject-hero p {
    font-size: 16px;
    opacity: 0.7;
}

body.light-mode .subject-hero h2 {
    color: #1e293b;
}

body {
    font-family: 'Poppins', sans-serif;
}

.subject-hero h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 38px;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 12px;
}
body.light-mode .subject-hero h2 {
    font-family: 'Poppins', sans-serif;
    font-size: 38px;
    color: #0f172a;
    font-weight: 700;
    letter-spacing: -0.5px;
    margin-bottom: 12px;
}

.subject-hero p {
    font-family: 'Poppins', sans-serif;
    font-size: 16px;
    font-weight: 400;
    opacity: 0.7;
      max-width: 1100px;
    margin: 0 auto;
    padding: 30px 20px 40px;
    text-align: center;
    position: relative;
}

body.light-mode .subject-hero p {
    color: #64748b;
     font-family: 'Poppins', sans-serif;
    font-size: 16px;
    font-weight: 400;
    opacity: 0.7;
      max-width: 1100px;
    margin: 0 auto;
    padding: 30px 20px 40px;
    text-align: center;
    position: relative;
}

.card-blue {
    background: linear-gradient(145deg, rgba(77,163,255,0.2), rgba(77,163,255,0.05));
    border-color: rgba(77,163,255,0.4);
}

.card-purple {
    background: linear-gradient(145deg, rgba(124,92,255,0.2), rgba(124,92,255,0.05));
    border-color: rgba(124,92,255,0.4);
}

.card-teal {
    background: linear-gradient(145deg, rgba(0,200,200,0.2), rgba(0,200,200,0.05));
    border-color: rgba(0,200,200,0.4);
}


/* Back button row */
.subject-top {
    text-align: left;
    margin-bottom: 25px;
    margin-left: 20px;
}

.back-btn{
position:relative;
left:auto;
top:auto;

display:flex;
align-items:center;
gap:6px;

color:#38bdf8;
font-size:14px;
text-decoration:none;
padding:6px 10px;
border-radius:6px;
transition:all .2s ease;
}

.back-btn:hover{
background:rgba(56,189,248,0.12);
}


.arrow{
font-size:18px;
}

body.light-mode .back-btn {
    color: #b68b2e;
}


@media (max-width:480px){

.subject-hero h2{
font-size:24px;
}

.chapters-container{
grid-template-columns:1fr;
gap:20px;
padding:30px 15px;
}

.chapter-card{
padding:20px;
}

}


/* MOBILE SUBJECT PAGE */

@media (max-width:480px){


.subject-hero{
margin:20px auto;
padding:25px 15px;
}


.subject-hero h2{

font-size:24px;

}

.subject-subtitle{

font-size:13px;

}

.chapters-container{

padding:0 15px;

}

.note-card:active{
transform:scale(0.97);
}

.chapters-container .note-card{

padding:20px;

}

.chapters-container .note-card:hover{
transform:translateY(-5px);
border-color:#38bdf8;
box-shadow:0 0 22px rgba(56,189,248,0.4);
}

}

.loader {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: #0f172a;

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

  z-index: 9999;
}

.loader::after {
  content: "";
  width: 40px;
  height: 40px;
  border: 4px solid #3b82f6;
  border-top-color: transparent;
  border-radius: 50%;

  animation: spin 0.8s linear infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

.loader {
  transition: opacity 0.3s ease;
}

body.light-mode .loader {
  background: #f8fafc;
  backdrop-filter: blur(2px);
}

body.light-mode .loader::after {
  border: 4px solid #d4af37;
  border-top-color: transparent;
}