@import url('https://fonts.googleapis.com/css2?family=DM+Sans:wght@400;500&family=DM+Serif+Display&display=swap');

:root {
  --teal-50:  #E1F5EE;
  --teal-100: #9FE1CB;
  --teal-400: #1D9E75;
  --teal-600: #0F6E56;
  --teal-800: #085041;
  --gray-50:  #F7F7F6;
  --gray-100: #EFEFED;
  --gray-200: #DEDDD9;
  --gray-400: #888780;
  --gray-600: #5F5E5A;
  --gray-900: #1C1C1A;
  --white: #ffffff;
  --sidebar-w: 240px;
  --topbar-h: 52px;
  --radius-sm: 6px;
  --radius-md: 8px;
  --radius-lg: 12px;
  --transition: 0.15s ease;
}

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

html, body {
  font-family: 'DM Sans', sans-serif;
  font-size: 15px;
  color: var(--gray-900);
  background: var(--gray-50);
  height: 100%;
}

/* ── TOPBAR ── */
.topbar {
  position: fixed; top: 0; left: 0; right: 0;
  height: var(--topbar-h);
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
  display: flex; align-items: center; justify-content: space-between;
  padding: 0 24px;
  z-index: 100;
}
.logo {
  font-family: 'DM Serif Display', serif;
  font-size: 18px; letter-spacing: -0.4px;
  text-decoration: none; color: var(--gray-900);
}
.logo span { color: var(--teal-400); }

.level-tabs { display: flex; gap: 4px; }
.level-tab {
  padding: 6px 16px; border-radius: var(--radius-md);
  font-size: 13px; font-weight: 500;
  cursor: pointer; border: 1px solid transparent;
  color: var(--gray-600); background: transparent;
  text-decoration: none; transition: all var(--transition);
}
.level-tab:hover { background: var(--gray-100); color: var(--gray-900); }
.level-tab.active { background: var(--teal-400); color: var(--white); }

.topbar-right { display: flex; align-items: center; gap: 10px; }
.teacher-btn {
  display: flex; align-items: center; gap: 6px;
  padding: 6px 14px; border-radius: var(--radius-md);
  font-size: 12px; font-weight: 500;
  border: 1px solid var(--gray-200);
  background: transparent; color: var(--gray-600);
  cursor: pointer; text-decoration: none;
  transition: all var(--transition);
}
.teacher-btn:hover { background: var(--gray-100); color: var(--gray-900); }
.teacher-btn svg { width: 13px; height: 13px; }

/* ── LAYOUT ── */
.layout {
  display: flex;
  margin-top: var(--topbar-h);
  min-height: calc(100vh - var(--topbar-h));
}

/* ── SIDEBAR ── */
.sidebar {
  width: var(--sidebar-w);
  flex-shrink: 0;
  background: var(--white);
  border-right: 1px solid var(--gray-200);
  position: fixed;
  top: var(--topbar-h);
  bottom: 0;
  overflow-y: auto;
  padding: 16px 0 40px;
}
.sb-section { margin-bottom: 2px; }
.sb-section-btn {
  width: 100%; display: flex; align-items: center; justify-content: space-between;
  padding: 7px 16px; background: none; border: none; cursor: pointer;
  text-align: left;
}
.sb-section-btn:hover { background: var(--gray-50); }
.sb-section-title {
  font-size: 10px; font-weight: 500; text-transform: uppercase;
  letter-spacing: 0.8px; color: var(--gray-400);
}
.sb-chevron {
  font-size: 11px; color: var(--gray-400);
  transition: transform 0.2s; display: inline-block;
}
.sb-chevron.open { transform: rotate(90deg); }
.sb-children { display: none; }
.sb-children.open { display: block; }
.sb-topic {
  display: flex; align-items: center;
  padding: 7px 16px 7px 20px;
  font-size: 13px; font-weight: 500;
  color: var(--gray-600); cursor: pointer;
  border-left: 2px solid transparent;
  text-decoration: none; transition: all var(--transition);
}
.sb-topic:hover { color: var(--gray-900); background: var(--gray-50); }
.sb-topic.active { color: var(--teal-600); border-left-color: var(--teal-400); background: var(--teal-50); }
.sb-subtopic {
  display: block; padding: 5px 16px 5px 32px;
  font-size: 12px; color: var(--gray-400);
  cursor: pointer; text-decoration: none;
  transition: all var(--transition);
}
.sb-subtopic:hover { color: var(--gray-600); background: var(--gray-50); }
.sb-subtopic.active { color: var(--teal-600); font-weight: 500; }

/* ── MAIN ── */
.main {
  margin-left: var(--sidebar-w);
  flex: 1; min-width: 0;
}

/* ── HERO ── */
.hero {
  padding: 28px 32px 22px;
  background: var(--white);
  border-bottom: 1px solid var(--gray-200);
}
.hero-label {
  font-size: 11px; font-weight: 500; color: var(--teal-400);
  letter-spacing: 0.8px; text-transform: uppercase; margin-bottom: 6px;
}
.hero-title {
  font-family: 'DM Serif Display', serif;
  font-size: 28px; letter-spacing: -0.5px; margin-bottom: 6px;
}
.hero-sub { font-size: 14px; color: var(--gray-600); }
.breadcrumb {
  margin-top: 10px; font-size: 12px; color: var(--gray-400);
}
.breadcrumb a { color: var(--gray-400); text-decoration: none; }
.breadcrumb a:hover { color: var(--teal-400); }
.breadcrumb span { color: var(--gray-600); }

/* ── CONTENT ── */
.content { padding: 24px 32px 48px; }

.section-label {
  font-size: 11px; font-weight: 500; color: var(--gray-400);
  text-transform: uppercase; letter-spacing: 0.6px;
  margin-bottom: 12px; padding-bottom: 8px;
  border-bottom: 1px solid var(--gray-200);
}

/* ── RESOURCE CARDS ── */
.resource-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(160px, 1fr));
  gap: 10px; margin-bottom: 28px;
}
.rc {
  background: var(--white);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 14px; cursor: pointer;
  text-decoration: none; display: block;
  transition: all var(--transition); position: relative;
}
.rc:hover { border-color: var(--teal-100); background: var(--teal-50); }
.rc.featured { border: 2px solid var(--teal-400); }
.rc-type {
  font-size: 10px; font-weight: 500; text-transform: uppercase;
  letter-spacing: 0.5px; color: var(--gray-400); margin-bottom: 4px;
}
.rc-name { font-size: 13px; font-weight: 500; color: var(--gray-900); margin-bottom: 4px; }
.rc-meta { font-size: 11px; color: var(--gray-400); }
.rc-badge {
  position: absolute; top: 10px; right: 10px;
  font-size: 9px; font-weight: 500;
  background: var(--teal-50); color: var(--teal-600);
  padding: 2px 6px; border-radius: 20px;
}

/* ── SIM CARDS ── */
.sim-card {
  display: flex; align-items: center; gap: 12px;
  background: var(--gray-50); border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg); padding: 12px 16px;
  margin-bottom: 8px; cursor: pointer;
  text-decoration: none; transition: all var(--transition);
}
.sim-card:hover { border-color: var(--teal-100); background: var(--teal-50); }
.sim-icon {
  width: 36px; height: 36px; border-radius: var(--radius-md);
  background: var(--teal-100); display: flex; align-items: center;
  justify-content: center; flex-shrink: 0;
}
.sim-icon svg { width: 18px; height: 18px; }
.sim-name { font-size: 13px; font-weight: 500; color: var(--gray-900); }
.sim-desc { font-size: 12px; color: var(--gray-600); }
.sim-arrow { margin-left: auto; color: var(--gray-400); font-size: 16px; }

/* ── PDF VIEWER ── */
.pdf-viewer-wrap {
  background: var(--white); border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg); overflow: hidden; margin-bottom: 20px;
}
.pdf-viewer-toolbar {
  display: flex; align-items: center; justify-content: space-between;
  padding: 10px 16px; border-bottom: 1px solid var(--gray-200);
  background: var(--gray-50);
}
.pdf-viewer-title { font-size: 13px; font-weight: 500; color: var(--gray-600); }
.pdf-download {
  display: flex; align-items: center; gap: 6px;
  font-size: 12px; color: var(--teal-600); text-decoration: none;
  padding: 4px 10px; border-radius: var(--radius-sm);
  border: 1px solid var(--teal-100); background: var(--teal-50);
  transition: all var(--transition);
}
.pdf-download:hover { background: var(--teal-100); }
.pdf-embed {
  width: 100%; height: 700px; border: none; display: block;
}

/* ── COMING SOON ── */
.coming {
  text-align: center; padding: 60px 20px;
  color: var(--gray-400);
}
.coming-icon { font-size: 36px; margin-bottom: 14px; }
.coming-title { font-size: 15px; font-weight: 500; color: var(--gray-600); margin-bottom: 6px; }
.coming-sub { font-size: 13px; margin-bottom: 20px; }
.coming-btn {
  display: inline-block; padding: 8px 20px;
  border-radius: var(--radius-md); border: 1px solid var(--gray-200);
  background: var(--white); color: var(--gray-600);
  font-size: 13px; text-decoration: none; cursor: pointer;
  transition: all var(--transition);
}
.coming-btn:hover { background: var(--gray-100); }

/* ── TEACHER LOGIN ── */
.login-wrap {
  max-width: 400px; margin: 80px auto; padding: 0 20px;
}
.login-card {
  background: var(--white); border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg); padding: 36px 32px;
}
.login-title {
  font-family: 'DM Serif Display', serif;
  font-size: 22px; margin-bottom: 6px;
}
.login-sub { font-size: 13px; color: var(--gray-600); margin-bottom: 28px; }
.login-label { font-size: 12px; font-weight: 500; color: var(--gray-600); margin-bottom: 6px; display: block; }
.login-input {
  width: 100%; padding: 9px 12px; font-size: 14px;
  border: 1px solid var(--gray-200); border-radius: var(--radius-md);
  margin-bottom: 16px; outline: none; font-family: inherit;
  transition: border-color var(--transition);
}
.login-input:focus { border-color: var(--teal-400); }
.login-btn {
  width: 100%; padding: 10px; font-size: 14px; font-weight: 500;
  background: var(--teal-400); color: var(--white);
  border: none; border-radius: var(--radius-md);
  cursor: pointer; font-family: inherit;
  transition: background var(--transition);
}
.login-btn:hover { background: var(--teal-600); }
.login-error {
  font-size: 12px; color: #c0392b; margin-top: 10px; display: none;
}

/* ── TEACHER DASHBOARD ── */
.teacher-grid {
  display: grid; grid-template-columns: repeat(auto-fill, minmax(200px, 1fr));
  gap: 12px; margin-bottom: 28px;
}
.tc {
  background: var(--white); border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg); padding: 16px;
  text-decoration: none; transition: all var(--transition);
}
.tc:hover { border-color: var(--teal-100); background: var(--teal-50); }
.tc-icon { font-size: 22px; margin-bottom: 8px; }
.tc-name { font-size: 13px; font-weight: 500; color: var(--gray-900); margin-bottom: 3px; }
.tc-meta { font-size: 11px; color: var(--gray-400); }
.logout-btn {
  font-size: 12px; color: var(--gray-400); background: none;
  border: 1px solid var(--gray-200); border-radius: var(--radius-md);
  padding: 5px 12px; cursor: pointer; transition: all var(--transition);
}
.logout-btn:hover { background: var(--gray-100); color: var(--gray-600); }

/* ── FOOTER ── */
.footer {
  margin-left: var(--sidebar-w);
  border-top: 1px solid var(--gray-200);
  padding: 16px 32px;
  font-size: 12px; color: var(--gray-400);
  display: flex; justify-content: space-between; align-items: center;
  background: var(--white);
}
.footer a { color: var(--gray-400); text-decoration: none; }
.footer a:hover { color: var(--teal-400); }

/* ── RESPONSIVE ── */
@media (max-width: 768px) {
  :root { --sidebar-w: 0px; }
  .sidebar { display: none; }
  .topbar { padding: 0 16px; }
  .logo span.tagline { display: none; }
  .hero { padding: 20px 16px 16px; }
  .content { padding: 16px 16px 40px; }
  .footer { margin-left: 0; }
}