/* =========================
   STUDY MATERIAL - styles.css
   ========================= */
:root {
  --bg-color: #97bcfc;
  --btn-color: #4073f5;
}

html { color-scheme: white; }

/* ===== RESET / BASE ===== */
html, body {
  height: 100%;
  margin: 0;
  padding: 0;
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

* { box-sizing: border-box; }

/* Body layout */
body {
  display: flex;
  flex-direction: column;
  min-height: 100vh;
}

/* Background image with overlay */
body.bg-app {
  position: relative;
}

body.bg-app::before {
  content: "";
  position: fixed;
  top: 0;
  left: 0;
  right: 0;
  bottom: 0;
  background: rgba(255, 255, 255, 0.6);
  z-index: -1;
}

/* Container */
.container {
  max-width: 1100px;
  margin: 50px auto 1px; /* leave space for fixed header */
  padding: 10px;
}
@media (min-width: 769px) { .container { padding: 35px; } }

/* Header */
header {
  background: #cfe3fc;
  padding: 6px 12px;
  display: flex;
  align-items: center;
  position: fixed;
  top: 0; left: 0; width: 100%;
  z-index: 1000;
  box-shadow: 0 5px 15px rgba(0,0,0,0.7);
  animation: slideDown 350ms ease;
}
@keyframes slideDown { from { transform: translateY(-100%); opacity:0 } to { transform: translateY(0); opacity:1 }}

/* Nav */
header nav {
  display: flex;
  gap: 8px;
  overflow-x: auto;
  white-space: nowrap;
  scrollbar-width: none;
}
header nav a {
  text-decoration: none;
  color: #1a1a1a;
  font-size: 0.9rem;
  font-weight: 450;
  padding: 6px 12px;
  border-radius: 6px;
  background: #93dffa;
  border: 1px solid #6974c7;
  flex-shrink: 0;
  transition: all 180ms ease;
}
header nav a:hover {
  background: #45afd6;
}

/* Headings and intro text */
.head-title {
  width: 100%;
  color: #111;
  text-align: center;
  margin: 10px auto 20px;
}
.head2-title {
  margin: 0;
  font-weight: 600;
  font-size: 1.05rem;
}

.lead {
  color: #323847;
  margin: 6px 0;
  font-weight: 450;
  line-height: 1.45;
  text-align: justify;
  z-index: 5;
}

.lead a { color: #0e5ae8; text-decoration: none; }
.lead a:hover { text-decoration: underline; }

/* Divider */
.divider {
  display: flex;
  align-items: center;
  margin: 24px 0;
}
.lines { flex: 1; height: 3px; display:flex; align-items:center; }
.divider-line { width: 100%; height: 3px; background: #1d387a; border-radius: 2px; }


/* Upload notes */
.upload-notes {
  width: 100%;
  margin: 12px auto;
  padding: 10px;
  background: transparent;
  border-radius: 10px;
  text-align: center;
}
.upload-btn {
  display: inline-block;
  margin-top: 10px;
  padding: 6px 11px;
  background: #155559;
  color: #ffffff;
  border-radius: 8px;
  font-weight: 700;
  text-decoration: none;
  border: none;
}
.upload-notes .lead { color: #111; }
.upload-btn:hover { background: #751aeb; }

/* PDF box (existing visual)  */
.pdf-box {
  width: 100%;
  display: flex;
  gap: 8px;
  margin: 20px 0 !important;
  background: #ffe5e5;
  border-radius: 10px;
  padding: 5px;
  align-items: center;
  z-index: 1;
  border: 1px solid #555;
}
.box-left { flex: 0 0 85px; display:flex; align-items:center; justify-content:center; }
.box-left img { width: 100%; height: auto; border-radius: 8px; object-fit: cover; }
.box-right { flex: 1 1 auto; display:flex; flex-direction:column; gap:7px; min-width: 0; }
.button-row { display:flex; gap:12px; align-items:center; }
.pdf-box button {
  background: var(--btn-color);
  color: #fff;
  padding: 5px 8px;
  border-radius: 8px;
  cursor: pointer;
  font-weight: 700;
  border: none;
}
.pdf-box button:hover { background: #751aeb; }

.file-title {
  margin: 0;
  font-size: 15px;
  color: #222;
  line-height: 1.2;
  font-weight: 500;
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.label {
  display: inline-block;
  font-size: 12px;
  padding: 2px 4px;
  margin-right: 4px;
  margin-left: 4px;
  background: #aaa;
  border-radius: 4px;
  color: #222;

}

@media (min-width: 769px) {
  .pdf-box { gap: 20px; padding: 12px; }
  .box-left { flex-basis: 160px; }
  .file-title { font-size: 16px; }
  button { padding: 10px 18px; border-width: 2px; }
}

/* =========================
   SECTION DRAWER / TABLE-LIKE HEADERS
   ========================= */

.doc-section {
  width: 100%;
  max-width: 500px;
  margin: 0 auto;
}

.section-toggle {
  width: 100%;
  max-width: 500px;
  display: flex;
  align-items: center;
  justify-content: center; 
  gap: 12px;
  cursor: pointer;
  padding: 10px 12px;
  background: var(--btn-color);
  border: 1px solid #333;
  border-radius: 14px;
  color: #fff;
  text-align: left;
  font-size: 1rem;
  font-weight: 600;
  transition: transform 160ms ease, background 160ms ease;
  outline: none;
}

.section-drawer {
  width: 100%;
  max-width: 500px;
  margin-bottom: 60px;
  overflow: hidden;
  height: 0;
  visibility: hidden;
  transition: height 320ms cubic-bezier(.2,.8,.2,1), visibility 0s linear 320ms;
  border-radius: 0 0 14px 14px;
  border: 1px solid #333;
  border-top: 1px solid var(--bg-color);
  background: var(--bg-color);
}

.section-drawer.open,
.section-drawer[aria-hidden="false"] {
  visibility: visible;
  transition: height 380ms cubic-bezier(.2,.8,.2,1);
}

.section-toggle.active {
  background: var(--bg-color);
  color: #111;
}

.section-toggle {
  transition: background 0.3s, color 0.3s;
}

.section-content {
  padding: 0 5px;
  box-sizing: border-box;
}

/* =========================
   YouTube drawer (keeps original style)
   ========================= */

/* Wrapper centers the button */
.yt-wrapper {
  display: flex;
  flex-direction: column;
  align-items: center;
  width: 100%;
  max-width: 500px;
}
.yt-toggle-btn {
  width: 100%;
  max-width: 500px;
  height: 40px;
  background: var(--btn-color);
  color: #fff;
  border-radius: 14px;
  font-size: 16px;
  font-weight: 600;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  border: 1px solid #333;
  transition: transform 150ms ease;
}

.yt-drawer { /* this will be used for the YouTube specific drawer */
  max-width: 500px;
  border-radius: 0 0 14px 14px;
  overflow: hidden;
  height: 0;
  visibility: hidden;
  transition: height 300ms ease, visibility 0s linear 300ms;
  background: var(--bg-color);
  border: 1px solid #333;
  border-top: 1px solid var(--bg-color);
}

.yt-drawer.yt-open,
.yt-drawer[aria-hidden="false"] {
  visibility: visible;
  transition: height 380ms ease;
}
.yt-drawer-inner { padding: 3px; }


@media (min-width: 769px) {
.doc-section , .section-toggle , .section-drawer , .yt-wrapper , .yt-toggle-btn , .yt-drawer {
  max-width: 800px;
}
.box-left { flex: 0 0 90px; }
}


/* YouTube list items (keeps your previous look) */
.yt-list { display:flex; flex-direction:column; gap:20px; padding: 2px; margin-top: 10px; margin-bottom:10px; }
.yt-item { display:flex; gap:10px; align-items:center; background:#ffe5e5; padding:6px; border-radius:8px; min-height:86px; overflow:hidden; border:1px solid #555; }
.yt-card-link { display:flex; gap:12px; align-items:center; text-decoration:none; color:inherit; width:100%; }
.yt-thumb { width:140px; height:78px; border-radius:6px; overflow:hidden; background:#111; position:relative; flex:0 0 140px; border: 1px solid #555; }
.yt-thumb img { width:100%; height:100%; object-fit:cover; display:block; }
.yt-badge { position:absolute; left:6px; top:6px; background:rgba(0,0,0,0.45); color:#fff; font-size:11px; padding:4px 6px; border-radius:4px; }
.yt-meta { display:flex; flex-direction:column; flex:1 1 auto; min-width:0; }
.yt-title { margin: 0; font-size: 14px; color: #222; line-height: 1.2; font-weight: 500; display: -webkit-box; -webkit-line-clamp: 3; -webkit-box-orient: vertical; overflow: hidden; }
.yt-sub { margin-top: 5px; color: #1224aa; font-size:14px; }

/* Responsive adjustments */
@media (min-width: 769px) {
  .yt-item { padding: 12px; }
  .yt-card-link { gap: 15px; }
  .yt-badge { padding: 7px 10px; }
  .yt-thumb { width:160px; height:90px; flex:0 0 160px; }
  .yt-title { font-size:15px; }
  .yt-drawer-inner { padding: 10px; }
}

/* =========================
   Overlay / PDF viewer / Legal popup
   ========================= */

#overlay {
  display: none;
  position: fixed;
  top: 0; left: 0;
  width: 100vw; height: 100vh;
  background: rgba(0,0,0,0.85);
  z-index: 9999;
}
.overlay-content {
  width: 100%;
  height: 100%;
  background: #fff;
  position: relative;
}
.close-btn {
    position: absolute;
    top: 32px;
    right: 0;
    margin: 0;
    background: #aaaaaa;
    color: #111;
    border: none;
    padding: 5px;
    font-size: 17px;
    cursor: pointer;
    border-radius: 2px;
    z-index: 1000;
}
#pdfFrame { width: 100%; height: 100%; border: none; }

/* No-legal popup */
.legal-popup-overlay {
  position: fixed; inset: 0;
  display:flex; align-items:center; justify-content:center;
  background: rgba(0,0,0,0.4);
  z-index: 10000;
}
.legal-popup {
  width: 320px;
  max-width: calc(100% - 60px);
  background: #c7e4fc;
  color: #333;
  border-radius: 8px;
  padding: 20px;
  position: relative;
  border: 1px solid #454;
  box-shadow: 0 10px 30px rgba(0,0,0,0.7);
  font-family: system-ui, -apple-system, "Segoe UI", Roboto, Arial;
}
.legal-popup h3 { margin: 0 0 10px 0; font-size: 18px; color: #870303; }
.legal-popup p { margin: 0; line-height: 1.4; color: #333; font-weight: 420; }
.legal-popup-close {
  position: absolute; top: 8px; right: 10px;
  background: transparent; border: none; font-size: 30px; cursor:pointer; color:#222; font-weight: 300;
}

/* =========================
   Footer
   ========================= */
footer {
  background: #a7cfc9;
  text-align: center;
  padding: 6px 10px;
  color: #333;
  font-size: 0.85rem;
  border-top: 1px solid #333;
  margin-top: auto;
  border-radius: 18px 18px 0 0;
}
footer a { color: #0c54b3; text-decoration:none; }
footer a:hover { text-decoration: underline; }

/* Small utility helpers */
.hidden { display:none !important; }
.center { display:flex; align-items:center; justify-content:center; }
:focus { outline: none; }

@media (prefers-color-scheme: dark) {
html { color-scheme: dark; }
body.bg-app::before  { background: rgba(0, 0, 0, 0.65); }
header { background: #0b2a6b; }
header nav a { color: #fff; background: transparent; }
header nav a:hover { background: #0b5ed7;}
footer { background: #111; color: #aaa; border-top: 1px solid #555555; }
footer a { color: #f7c2d9; }
.lead { font-weight: 400; color: #cfd3fa; }
.lead a { color: #79a7fc; }
.head-title { color: #eee; }
.divider-line { background: #7995fc; }
:root {
  --bg-color: #334b69;
  --btn-color: #04617a;
}
.section-toggle.active { color: #ddd; }
.section-toggle, .section-drawer { border: 1px solid #888; }
.section-drawer { border-top: 1px solid var(--bg-color); }
.pdf-box { background: #373746; border: 1px solid #888; }
.file-title { color: #eee; }
.pdf-box button { background: #adf; color: #222; }
.pdf-box button:hover { background: #aaf; }
.label { background: #555; color: #eee; }
.yt-item { background: #373746; border: 1px solid #888; } 
.yt-title { color: #eee; }
.yt-sub { color: #bee; }
.close-btn { background: #333; color: #ccc; }
.upload-btn { background: #adf; color: #222; }
.upload-notes .lead { color: #eee; }
.upload-btn:hover { background: #aaf; }
.legal-popup { background: #444; color: #ddd; border: 2px solid #888; }
.legal-popup h3 { color: #ffc7c7; }
.legal-popup p { color: #ddd; }
.legal-popup-close { color: #ddd; }

}


@media (max-width: 768px) {
    /* Hide scrollbar for Chrome, Safari and Edge */
    *::-webkit-scrollbar {
        display: none;
    }

    /* Hide scrollbar for Firefox */
    * {
        scrollbar-width: none;
    }

    /* Hide scrollbar for IE and old Edge */
    * {
        -ms-overflow-style: none;
    }
}

/* End of stylesheet */