* { margin:0; padding:0; box-sizing:border-box; }
body {
  font-family: 'Segoe UI', Roboto, system-ui, sans-serif;
  background: #f2f6fc;
  padding: 16px;
  width: 100%;
  max-width: 1000px;
  margin: auto;
  min-height: 100vh;
}
.box {
  background: white;
  padding: 24px 20px 30px;
  border-radius: 28px;
  box-shadow: 0 12px 40px rgba(0, 80, 200, 0.10);
  margin-top: 18px;
  transition: 0.2s;
}

.header-center {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  margin-bottom: 20px;
}

#logo {
  width: 120px;
  height: 120px;
  object-fit: cover;
  border-radius: 28px;
  box-shadow: 0 6px 18px rgba(0,0,0,0.08);
  display: block;
}

.app-title {
  text-align: center;
  font-weight: 700;
  font-size: 28px;
  color: #0b1e3a;
  margin-top: 6px;
}
.app-title .sub {
  color: #0066ff;
  font-weight: 700;
}

select, button {
  width: 100%;
  padding: 16px 14px;
  margin-top: 12px;
  font-size: 17px;
  border-radius: 16px;
  border: 1px solid #d9e2ef;
  background: white;
  font-weight: 500;
  transition: 0.2s;
}
select:focus {
  border-color: #0066ff;
  outline: none;
  box-shadow: 0 0 0 3px rgba(0,102,255,0.12);
}
button {
  background: #0066ff;
  color: white;
  font-weight: 600;
  border: none;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,102,255,0.20);
  transition: 0.15s;
}
button:hover { background: #0052cc; transform: scale(0.98); }
#devBtn { background: #2d3b4f; box-shadow: none; }
#installBtn { background: #16a34a; box-shadow: 0 4px 12px rgba(22,163,74,0.3); }
#msg {
  margin: 16px 0 8px;
  background: #eef5ff;
  padding: 14px 18px;
  border-radius: 16px;
  font-size: 15px;
  border-left: 5px solid #0066ff;
  transition: 0.2s;
}
.subject-section {
  margin-top: 28px;
  padding: 20px 18px;
  background: #f8fbff;
  border-radius: 24px;
  border: 1px solid #e6edf8;
  transition: 0.25s;
}
.subject-section h3 {
  font-size: 20px;
  display: flex;
  align-items: center;
  gap: 8px;
  color: #0b1e3a;
  margin-bottom: 14px;
}
.subject-section h3 span {
  background: #0066ff10;
  padding: 4px 12px;
  border-radius: 40px;
  font-size: 14px;
  color: #0066ff;
  font-weight: 600;
}
.subject-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 12px;
}
.subject-tag {
  background: white;
  padding: 8px 18px;
  border-radius: 40px;
  font-size: 14px;
  font-weight: 500;
  color: #1a2b44;
  border: 1px solid #dce5f2;
  transition: 0.15s;
  cursor: default;
}
.subject-tag:hover {
  border-color: #0066ff;
  background: #f0f6ff;
  transform: translateY(-2px);
}
.empty-subjects { color: #7a8aa0; font-size: 15px; padding: 6px 0; }
.modal {
  position: fixed; inset: 0; background: rgba(0,0,0,0.5);
  display: none; justify-content: center; align-items: center;
  padding: 15px; z-index: 9999; backdrop-filter: blur(4px);
}
.modal.active { display: flex; }
.modal-box {
  width: 100%; max-width: 600px; height: 92vh;
  background: #fff; border-radius: 28px; overflow: hidden;
  display: flex; flex-direction: column;
  animation: popup .3s ease; box-shadow: 0 30px 60px rgba(0,0,0,0.25);
}
@keyframes popup { from { transform: scale(0.94); opacity:0; } to { transform:scale(1); opacity:1; } }
.modal-top {
  padding: 14px 18px; background: #f1f6fd;
  display: flex; justify-content: space-between; align-items: center;
  font-size: 18px; font-weight: 600; flex-shrink:0;
}
.btn-group { display: flex; gap: 10px; }
.close-btn {
  background: #eef2f7; color: #1e2a44; padding: 8px 18px;
  border: none; border-radius: 40px; font-weight: 600; cursor: pointer;
  font-size: 14px;
}
#downloadPDFBtn { background: #0066ff; color: white; }
iframe { width: 100%; height: 100%; flex: 1; border: 0; }

/* ===========================
   DEVELOPER MODAL
=========================== */

.developer-modal{
    max-width:430px;
    width:100%;
    height:auto;
    max-height:92vh;
    border-radius:28px;
    overflow:hidden;
    background:#fff;
    box-shadow:0 25px 60px rgba(0,0,0,.25);
}

.dev-header{
    position:relative;
    padding:35px 25px 30px;
    text-align:center;
    background:linear-gradient(135deg,#0066ff,#00b4ff);
    color:#fff;
}

.dev-close{
    position:absolute;
    top:16px;
    right:16px;
    width:40px;
    height:40px;
    border:none;
    border-radius:50%;
    background:rgba(255,255,255,.18);
    cursor:pointer;
    transition:.25s;
}

.dev-close:hover{
    background:rgba(255,255,255,.3);
}

.dev-close::before,
.dev-close::after{
    content:"";
    position:absolute;
    left:50%;
    top:50%;
    width:18px;
    height:3px;
    background:#fff;
    border-radius:10px;
}

.dev-close::before{
    transform:translate(-50%,-50%) rotate(45deg);
}

.dev-close::after{
    transform:translate(-50%,-50%) rotate(-45deg);
}

.dev-photo-wrap{
    width:120px;
    height:120px;
    margin:0 auto 15px;
    border-radius:50%;
    background:#fff;
    padding:5px;
    box-shadow:0 10px 30px rgba(0,0,0,.18);
}

.dev-photo {
    width: 100%;
    height: 100%;
    border-radius: 50%;
    object-fit: cover;
    object-position: center top;
    display: block;
}

.dev-header h2{
    font-size:28px;
    font-weight:700;
    margin:10px 0 5px;
    color:#fff;
}

.dev-role{
    display:block;
    font-size:16px;
    font-weight:700;
    margin-bottom:6px;
}

.dev-title{
    display:block;
    font-size:14px;
    opacity:.95;
    line-height:1.5;
}

.dev-body{
    padding:22px;
}

.dev-card{
    display:flex;
    justify-content:space-between;
    align-items:center;
    gap:15px;
    padding:14px 0;
    border-bottom:1px solid #eef2f7;
}

.dev-card:last-child{
    border-bottom:none;
}

.dev-card b{
    min-width:90px;
    color:#1f2937;
    font-size:15px;
}

.dev-card a{
    color:#0066ff;
    text-decoration:none;
    font-weight:600;
    transition:.2s;
}

.dev-card a:hover{
    color:#ff0000;
}

.dev-card span{
    background:#eef4ff;
    color:#0066ff;
    padding:5px 12px;
    border-radius:30px;
    font-size:13px;
    font-weight:600;
}

.youtube-btn{
    display:flex;
    justify-content:center;
    align-items:center;
    width:100%;
    margin:22px 0 18px;
    padding:15px;
    background:#ff0000;
    color:#fff !important;
    text-decoration:none;
    border-radius:50px;
    font-size:16px;
    font-weight:700;
    transition:.25s;
    box-shadow:0 8px 20px rgba(255,0,0,.25);
}

.youtube-btn:hover{
    background:#d80000;
    color:#fff !important;
    transform:translateY(-2px);
}

.dev-about{
    margin-top:15px;
    padding-top:18px;
    border-top:1px solid #eef2f7;
    text-align:center;
    font-size:14px;
    color:#64748b;
    line-height:1.7;
}

@media(max-width:600px){

    .developer-modal{
        max-width:95%;
    }

    .dev-photo-wrap{
        width:100px;
        height:100px;
    }

    .dev-header h2{
        font-size:24px;
    }

    .dev-card{
        flex-direction:column;
        align-items:flex-start;
        gap:6px;
    }

    .dev-card b{
        min-width:auto;
    }
}

/* Footer Animation */
@keyframes footerFadeUp {
    0% {
        opacity: 0;
        transform: translateY(25px);
    }
    100% {
        opacity: 1;
        transform: translateY(0);
    }
}

#myfooter {
    animation: footerFadeUp 1.3s ease-out forwards;
    width: 100%;
    text-align: center;
    padding: 10px 0px;
    font-size: 8px;
    margin-top: 10px;
    opacity: 0;
}
@media (max-width: 600px) {
  .box { padding: 16px; }
  .subject-tag { font-size: 13px; padding: 6px 14px; }
  .dev-photo-wrap { width: 100px; height: 100px; }
  .developer-modal { max-width: 94vw; }
  .dev-header h2 { font-size: 22px; }
  .dev-info-label { min-width: 70px; font-size: 14px; }
  .dev-info-value { font-size: 14px; }
}
a:link, a:visited { color: #0066ff; }
a:hover { color: #ff0000; }