/* ============ RESET & BASE ============ */
*, *::before, *::after { box-sizing: border-box; }
html { scroll-behavior: smooth; }
body {
  margin: 0;
  font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
  font-weight: 500;
  color: #1a1a2e;
  background: linear-gradient(135deg, #f4f9ff 0%, #fff7ec 50%, #f1f8f1 100%);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

/* ============ HEADER ============ */
.site-header {
  background: linear-gradient(135deg, #143a66 0%, #3a2070 60%, #7a4d05 100%);
  color: #fff;
  padding: 36px 18px;
  text-align: center;
  border-bottom: 5px solid #d18b1f;
}
.site-header h1 {
  font-size: clamp(1.6rem, 3.2vw, 2.4rem);
  margin: 0 0 8px;
  letter-spacing: 0.3px;
  font-weight: 700;
  text-shadow: 0 2px 6px rgba(0,0,0,0.25);
}
.subtitle { margin: 4px 0; font-size: 1.05rem; font-weight: 600; color: #ffe9b8; }
.meta { margin: 4px 0 18px; font-size: 0.95rem; color: #d7e6ff; }

/* ============ BUTTONS ============ */
.btn {
  cursor: pointer;
  border: none;
  font-weight: 700;
  border-radius: 8px;
  padding: 10px 18px;
  font-size: 0.95rem;
  transition: transform 0.15s, box-shadow 0.2s, background 0.2s;
  font-family: inherit;
}
.btn:active { transform: translateY(1px); }
.btn-print {
  background: #fff;
  color: #143a66;
  border: 2px solid #d18b1f;
}
.btn-print:hover { background: #ffe9b8; }

.btn-small { padding: 6px 12px; font-size: 0.88rem; }

.btn-toggle {
  background: #2a6fb5;
  color: #fff;
  margin-top: 6px;
}
.btn-toggle:hover { background: #1e5a8f; }

/* ============ NAV ============ */
.topnav {
  position: sticky;
  top: 0;
  background: #fff;
  border-bottom: 2px solid rgba(42, 111, 181, 0.25);
  padding: 10px 14px;
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  z-index: 50;
  box-shadow: 0 2px 8px rgba(0,0,0,0.08);
}
.nav-btn {
  background: #eef4fb;
  color: #143a66;
  border: 1.5px solid rgba(42, 111, 181, 0.35);
  padding: 6px 12px;
  border-radius: 999px;
  font-size: 0.82rem;
  font-weight: 700;
  cursor: pointer;
  transition: background 0.15s, color 0.15s, transform 0.1s;
}
.nav-btn:hover { background: #2a6fb5; color: #fff; transform: translateY(-1px); }
.nav-btn.highlight {
  background: #fff3df;
  color: #7a4d05;
  border-color: #d18b1f;
}
.nav-btn.highlight:hover { background: #d18b1f; color: #fff; }

/* ============ LAYOUT ============ */
.container {
  max-width: 1100px;
  margin: 24px auto;
  padding: 0 16px 60px;
}

/* ============ CARDS ============ */
.card {
  background: #ffffff;
  border-radius: 14px;
  padding: 26px 26px 24px;
  margin: 22px 0;
  border: 1.5px solid rgba(20, 58, 102, 0.12);
  box-shadow: 0 4px 14px rgba(20, 58, 102, 0.06);
}
.card h2 {
  margin: 0 0 14px;
  font-size: clamp(1.15rem, 2vw, 1.5rem);
  font-weight: 800;
  padding-bottom: 8px;
  border-bottom: 2.5px solid;
}
.card h3 {
  margin: 18px 0 8px;
  font-weight: 700;
  font-size: 1.07rem;
  color: #143a66;
}
.card ul, .card ol { padding-left: 22px; }
.card li { margin: 5px 0; }
.tip {
  background: #fffbea;
  border-left: 4px solid #d18b1f;
  padding: 10px 14px;
  border-radius: 6px;
  margin-top: 10px;
  font-weight: 600;
}

/* Card color variants */
.card-blue    { border-left: 6px solid #2a6fb5; }
.card-blue h2 { color: #143a66; border-color: #2a6fb5; }

.card-green    { border-left: 6px solid #2e8b57; }
.card-green h2 { color: #1e5a36; border-color: #2e8b57; }

.card-saffron    { border-left: 6px solid #d18b1f; }
.card-saffron h2 { color: #7a4d05; border-color: #d18b1f; }

.card-violet    { border-left: 6px solid #6b46a8; }
.card-violet h2 { color: #3a2070; border-color: #6b46a8; }

.card-red    { border-left: 6px solid #b53a3a; background: #fff5f5; }
.card-red h2 { color: #6b1717; border-color: #b53a3a; }

/* ============ TABLES ============ */
.tbl {
  width: 100%;
  border-collapse: collapse;
  margin: 12px 0;
  font-size: 0.95rem;
  border: 1.5px solid rgba(20, 58, 102, 0.18);
  border-radius: 8px;
  overflow: hidden;
}
.tbl th, .tbl td {
  border: 1px solid rgba(20, 58, 102, 0.15);
  padding: 10px 12px;
  text-align: left;
  vertical-align: top;
}
.tbl th {
  background: linear-gradient(135deg, #143a66, #3a2070);
  color: #fff;
  font-weight: 700;
}
.tbl tr:nth-child(even) td { background: #f6faff; }

/* ============ FLOWCHART ============ */
.flow-wrapper {
  width: 100%;
  overflow-x: auto;
  padding: 6px;
  background: #fbfdff;
  border-radius: 10px;
  border: 1.5px solid rgba(42, 111, 181, 0.25);
}
.flow-svg { width: 100%; min-width: 760px; height: auto; }

/* ============ MIND MAP ============ */
.mindmap {
  position: relative;
  width: 100%;
  height: 520px;
  margin: 18px 0;
  background: radial-gradient(circle at center, #f4f9ff 0%, #f1f8f1 100%);
  border-radius: 14px;
  border: 1.5px solid rgba(46, 139, 87, 0.3);
  overflow: hidden;
}
.mm-center {
  position: absolute;
  left: 50%; top: 50%;
  transform: translate(-50%, -50%);
  width: 140px; height: 140px;
  border-radius: 50%;
  background: linear-gradient(135deg, #2e8b57, #143a66);
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  font-weight: 800;
  font-size: 1rem;
  box-shadow: 0 6px 20px rgba(46, 139, 87, 0.4);
  z-index: 3;
}
.mm-node {
  position: absolute;
  width: 160px;
  padding: 10px 12px;
  background: #fff;
  border-radius: 10px;
  text-align: center;
  font-weight: 700;
  font-size: 0.9rem;
  color: #143a66;
  box-shadow: 0 3px 10px rgba(20, 58, 102, 0.12);
  border: 2px solid #2a6fb5;
  z-index: 2;
}
.mm-node span { display: block; font-weight: 600; font-size: 0.78rem; color: #444; margin-top: 4px; }

.mm-n1 { top: 4%;   left: 50%; transform: translateX(-50%); border-color: #2a6fb5; }
.mm-n2 { top: 18%;  right: 3%; border-color: #d18b1f; }
.mm-n3 { top: 42%;  right: 2%; border-color: #6b46a8; }
.mm-n4 { bottom: 18%; right: 3%; border-color: #b53a3a; }
.mm-n5 { bottom: 4%;  left: 50%; transform: translateX(-50%); border-color: #2e8b57; }
.mm-n6 { bottom: 18%; left: 3%; border-color: #2a6fb5; }
.mm-n7 { top: 42%;  left: 2%; border-color: #d18b1f; }
.mm-n8 { top: 18%;  left: 3%; border-color: #6b46a8; }

/* ============ ROADMAP ============ */
.roadmap {
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin-top: 14px;
}
.road-step {
  display: flex;
  gap: 14px;
  align-items: flex-start;
  background: #fff;
  border-left: 5px solid #6b46a8;
  padding: 12px 16px;
  border-radius: 10px;
  box-shadow: 0 2px 6px rgba(107, 70, 168, 0.10);
}
.road-step:nth-child(odd)  { border-left-color: #2a6fb5; }
.road-step:nth-child(even) { border-left-color: #2e8b57; }
.step-num {
  flex: none;
  width: 36px; height: 36px;
  border-radius: 50%;
  background: linear-gradient(135deg, #6b46a8, #143a66);
  color: #fff;
  font-weight: 800;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

/* ============ MCQ ============ */
.mcq-toolbar {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 14px;
}
.mcq {
  background: #fbfdff;
  border-radius: 10px;
  padding: 14px 16px;
  margin: 12px 0;
  border: 1.5px solid rgba(42, 111, 181, 0.2);
}
.mcq ol { margin: 6px 0 8px 18px; }
.mcq li { margin: 2px 0; font-weight: 600; }
.answer {
  background: #e7f7ec;
  border-left: 4px solid #2e8b57;
  padding: 10px 12px;
  border-radius: 6px;
  margin-top: 10px;
  font-weight: 600;
}
.hidden { display: none; }

.diff {
  display: inline-block;
  margin-left: 8px;
  padding: 2px 8px;
  font-size: 0.74rem;
  font-weight: 700;
  border-radius: 20px;
  vertical-align: middle;
}
.diff.easy     { background: #d8f0e0; color: #1e5a36; }
.diff.moderate { background: #fff3df; color: #7a4d05; }
.diff.hard     { background: #fde2e2; color: #6b1717; }

/* ============ TOP BUTTON ============ */
.top-btn {
  position: fixed;
  bottom: 24px;
  right: 22px;
  width: 46px; height: 46px;
  border-radius: 50%;
  border: none;
  background: #143a66;
  color: #fff;
  font-size: 1.3rem;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(0,0,0,0.25);
  display: none;
  z-index: 60;
}
.top-btn:hover { background: #2a6fb5; }

/* ============ FOOTER ============ */
.site-footer {
  background: #143a66;
  color: #d7e6ff;
  text-align: center;
  padding: 14px;
  font-size: 0.88rem;
  font-weight: 600;
}
.brand {
  margin-top: 10px;
  font-weight: 700;
  color: #6b1717;
}

/* ============ RESPONSIVE ============ */
@media (max-width: 760px) {
  .card { padding: 18px 16px; }
  .nav-btn { font-size: 0.74rem; padding: 5px 9px; }
  .mindmap { height: 720px; }
  .mm-center { width: 110px; height: 110px; font-size: 0.85rem; }
  .mm-node { width: 130px; font-size: 0.78rem; padding: 8px; }
  .mm-n1 { top: 1%;  left: 50%; }
  .mm-n2 { top: 13%; right: 2%; }
  .mm-n3 { top: 30%; right: 2%; }
  .mm-n4 { bottom: 30%; right: 2%; }
  .mm-n5 { bottom: 1%; left: 50%; }
  .mm-n6 { bottom: 30%; left: 2%; }
  .mm-n7 { top: 30%; left: 2%; }
  .mm-n8 { top: 13%; left: 2%; }
}

/* ============ PRINT ============ */
@media print {
  body { background: #fff; color: #000; }
  .topnav, .top-btn, .btn-print, .btn-toggle, .mcq-toolbar, .site-footer { display: none !important; }
  .card {
    page-break-inside: avoid;
    box-shadow: none;
    border: 1px solid #999;
    margin: 10px 0;
    padding: 14px;
  }
  .answer { display: block !important; }
  .hidden { display: block !important; }
  .site-header { background: #143a66 !important; -webkit-print-color-adjust: exact; print-color-adjust: exact; }
  .flow-svg { max-width: 100%; }
  a, button { color: #000; }
  h1, h2, h3 { page-break-after: avoid; }
}