:root{
  --sky-50: #eef7ff;
  --sky-100: #d9ecff;
  --sky-200: #b8dcff;
  --blue-500: #1f7ae0;
  --blue-600: #145fb6;
  --blue-700: #0f4a91;
  --blue-850: #092e5d;
  --navy-950: #03111f;
  --ink: #102033;
  --muted: #607086;
  --panel: #ffffff;
  --panel-soft: #f8fbff;
  --line: rgba(15, 74, 145, .16);
  --aqua: #37c7d4;
  --sand: #f3ead8;
  --shadow: 0 24px 60px rgba(3, 17, 31, .18);
}

*{ box-sizing:border-box; }

body{
  margin:0;
  min-height:100vh;
  color: var(--ink);
  font-family:'Inter', system-ui, sans-serif;
  background:
    linear-gradient(135deg, rgba(31,122,224,.12) 0 25%, transparent 25% 50%, rgba(55,199,212,.10) 50% 75%, transparent 75%),
    linear-gradient(180deg, var(--sky-50), var(--sand));
  background-size: 42px 42px, auto;
  padding: 28px 16px 48px;
}

.notebook{
  width: min(1120px, 100%);
  margin: 0 auto;
  position: relative;
  overflow: hidden;
  border-radius: 6px;
  background: rgba(255,255,255,.76);
  border: 1px solid rgba(255,255,255,.82);
  box-shadow: var(--shadow);
}

.spiral{
  display:none;
}

.masthead{
  position: relative;
  display:grid;
  grid-template-columns: minmax(0, 1fr);
  gap: 12px;
  padding: clamp(28px, 5vw, 58px) clamp(22px, 6vw, 72px);
  background:
    linear-gradient(100deg, rgba(3,17,31,.94), rgba(9,46,93,.92) 55%, rgba(31,122,224,.84)),
    var(--blue-850);
  color: #fff;
  isolation:isolate;
}

.masthead::before{
  content:"";
  position:absolute;
  inset:auto -12% -34% 42%;
  height: 190px;
  border-radius: 999px;
  background: rgba(55,199,212,.26);
  filter: blur(2px);
  transform: rotate(-10deg);
  z-index:-1;
}

.masthead::after{
  content:"";
  position:absolute;
  inset: 0;
  background:
    linear-gradient(90deg, transparent 0 78%, rgba(255,255,255,.10) 78% 79%, transparent 79%),
    linear-gradient(180deg, transparent 0 72%, rgba(255,255,255,.08) 72% 73%, transparent 73%);
  background-size: 90px 70px;
  opacity:.7;
  pointer-events:none;
}

.masthead > *{
  position:relative;
  z-index:1;
}

.kicker{
  width: fit-content;
  margin:0;
  padding: 8px 12px;
  border-left: 4px solid var(--aqua);
  background: rgba(255,255,255,.10);
  color: #d8efff;
  font-size:.78rem;
  font-weight:800;
  line-height:1.55;
  letter-spacing:.08em;
  text-transform:uppercase;
}

.masthead h1{
  margin: 4px 0 0;
  color:#ffffff;
  font-size: clamp(2.2rem, 7vw, 5.35rem);
  line-height:.95;
  font-weight:800;
}

.masthead p{
  margin:0;
  max-width: 40rem;
  color: rgba(238,247,255,.88);
  font-size: 1rem;
  line-height:1.7;
}

.tabs{
  display:flex;
  gap:0;
  padding: 0 clamp(14px, 5vw, 56px);
  background: var(--panel);
  border-bottom: 1px solid var(--line);
}

.tab{
  min-height: 58px;
  border: none;
  border-bottom: 4px solid transparent;
  background: transparent;
  color: var(--muted);
  cursor:pointer;
  font: inherit;
  font-weight:800;
  padding: 0 22px;
  transition: color .18s ease, border-color .18s ease, background .18s ease;
}

.tab .num{
  margin-right: 8px;
  color: var(--blue-500);
  font-family:'IBM Plex Mono', monospace;
  font-size:.8rem;
}

.tab:hover{
  color: var(--blue-700);
  background: var(--sky-50);
}

.tab[aria-selected="true"]{
  color: var(--blue-850);
  border-bottom-color: var(--blue-500);
  background: linear-gradient(180deg, #ffffff, var(--sky-50));
}

.page{
  min-height: 440px;
  padding: clamp(20px, 4vw, 42px) clamp(16px, 5vw, 56px) clamp(36px, 5vw, 58px);
  background:
    linear-gradient(180deg, var(--panel-soft), #ffffff 58%, var(--sky-50));
}

.page-inner{
  width:100%;
}

.sheet-head{
  display:grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items:center;
  gap: 16px;
  margin-bottom: 24px;
  padding-bottom: 18px;
  border-bottom: 1px solid var(--line);
}

.tab-index{
  display:grid;
  place-items:center;
  width: 50px;
  height: 50px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--blue-600), var(--aqua));
  color: #fff;
  font-family:'IBM Plex Mono', monospace;
  font-size: 1rem;
  font-weight: 800;
  box-shadow: 0 10px 22px rgba(31,122,224,.28);
}

.sheet-head > div{
  min-width:0;
}

.sheet-head h2{
  margin:0 0 5px;
  color: var(--navy-950);
  font-size: clamp(1.35rem, 3vw, 2.05rem);
  line-height:1.15;
}

.sheet-sub{
  margin:0;
  color: var(--muted);
  font-size:.96rem;
  line-height:1.55;
}

.records{
  display:grid;
  grid-template-columns: repeat(auto-fit, minmax(245px, 1fr));
  gap: 18px;
  margin-bottom: 22px;
}

.record{
  position:relative;
  overflow:hidden;
  background: var(--panel);
  border: 1px solid var(--line);
  border-radius: 6px;
  padding: 20px;
  box-shadow: 0 12px 28px rgba(15,74,145,.10);
}

.record::before{
  content:"";
  position:absolute;
  inset:0 auto 0 0;
  width: 5px;
  background: linear-gradient(180deg, var(--blue-500), var(--aqua));
}

.record-label{
  margin:0 0 14px;
  color: var(--blue-700);
  font-size:.75rem;
  font-weight:800;
  text-transform:uppercase;
  letter-spacing:.12em;
}

.record-grid{
  margin:0;
  display:grid;
  grid-template-columns: minmax(92px, max-content) 1fr;
  gap: 8px 14px;
  font-size:.92rem;
}

.record-grid dt{
  color: var(--muted);
  font-weight:800;
}

.record-grid dd{
  margin:0;
  color: var(--ink);
}

.sheet[data-sheet="1.1"]{
  display:grid;
  gap: 24px;
}

.sheet[data-sheet="1.1"] .sheet-head{
  padding: 22px;
  border: 1px solid rgba(31,122,224,.18);
  border-bottom: 4px solid var(--blue-500);
  border-radius: 6px;
  background:
    linear-gradient(135deg, rgba(31,122,224,.10), rgba(55,199,212,.14)),
    #ffffff;
  box-shadow: 0 14px 32px rgba(15,74,145,.10);
}

.sheet[data-sheet="1.1"] .tab-index{
  border-radius: 6px;
  background: var(--navy-950);
  box-shadow: inset 0 -4px 0 var(--aqua);
}

.sheet[data-sheet="1.1"] .records{
  grid-template-columns: repeat(2, minmax(0, 1fr));
  gap: 20px;
  margin-bottom: 0;
}

.sheet[data-sheet="1.1"] .record{
  min-height: 230px;
  padding: 0;
  border: none;
  border-radius: 6px;
  background: #ffffff;
  box-shadow: 0 18px 38px rgba(3,17,31,.14);
}

.sheet[data-sheet="1.1"] .record::before{
  inset: 0 0 auto;
  width: auto;
  height: 72px;
  background:
    linear-gradient(135deg, rgba(3,17,31,.92), rgba(15,74,145,.88)),
    var(--blue-850);
}

.sheet[data-sheet="1.1"] .record-label{
  position: relative;
  z-index: 1;
  margin: 0;
  padding: 22px 22px 28px;
  color: #ffffff;
  letter-spacing: .16em;
}

.sheet[data-sheet="1.1"] .record-grid{
  position: relative;
  z-index: 1;
  margin: -10px 18px 18px;
  padding: 18px;
  grid-template-columns: 1fr;
  gap: 10px;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel-soft);
}

.sheet[data-sheet="1.1"] .record-grid dt{
  color: var(--blue-600);
  font-size: .72rem;
  letter-spacing: .12em;
  text-transform: uppercase;
}

.sheet[data-sheet="1.1"] .record-grid dd{
  margin: -8px 0 6px;
  padding-bottom: 10px;
  border-bottom: 1px solid rgba(15,74,145,.10);
  color: var(--navy-950);
  font-size: 1rem;
  font-weight: 700;
}

.sheet[data-sheet="1.1"] .record-grid dd:last-child{
  margin-bottom: 0;
  padding-bottom: 0;
  border-bottom: none;
}

.sheet[data-sheet="1.1"] .dump{
  border-color: rgba(3,17,31,.12);
  background: linear-gradient(180deg, #ffffff, var(--sky-50));
}

.sheet[data-sheet="1.1"] .dump summary{
  color: var(--navy-950);
}

.sheet[data-sheet="1.2"]{
  display:grid;
  gap: 22px;
}

.sheet[data-sheet="1.2"] .sheet-head{
  display:grid;
  grid-template-columns: auto minmax(0, 1fr) auto;
  align-items:center;
  gap: 16px;
  margin-bottom: 0;
  padding: 18px;
  border: 1px solid rgba(15,74,145,.18);
  border-radius: 6px;
  background:
    linear-gradient(90deg, rgba(9,46,93,.08), rgba(55,199,212,.10)),
    #ffffff;
  box-shadow: 0 12px 28px rgba(15,74,145,.08);
}

.sheet[data-sheet="1.2"] .tab-index{
  border-radius: 6px;
  background: linear-gradient(135deg, var(--aqua), var(--blue-600));
}

.sheet[data-sheet="1.2"] .table-picker-btn{
  min-width: 180px;
}

.sheet[data-sheet="1.2"] .table-wrap{
  border: none;
  border-radius: 6px;
  background: #ffffff;
  box-shadow: 0 18px 42px rgba(3,17,31,.14);
}

.sheet[data-sheet="1.2"] .ledger{
  border-collapse: separate;
  border-spacing: 0;
}

.sheet[data-sheet="1.2"] .ledger th{
  position: sticky;
  top: 0;
  background: linear-gradient(180deg, var(--navy-950), var(--blue-850));
  border-bottom: 3px solid var(--aqua);
}

.sheet[data-sheet="1.2"] .ledger th:first-child{
  border-top-left-radius: 6px;
}

.sheet[data-sheet="1.2"] .ledger th:last-child{
  border-top-right-radius: 6px;
}

.sheet[data-sheet="1.2"] .ledger td{
  border-bottom: 1px solid rgba(15,74,145,.10);
  border-right: 1px solid rgba(15,74,145,.07);
  background: rgba(255,255,255,.72);
}

.sheet[data-sheet="1.2"] .ledger td:last-child{
  border-right: none;
}

.sheet[data-sheet="1.2"] .ledger tbody tr:nth-child(even) td{
  background: #f2f8ff;
}

.sheet[data-sheet="1.2"] .ledger tbody tr:hover td{
  background: #dff0ff;
}

.sheet[data-sheet="1.2"] .table-note{
  width: fit-content;
  margin-top: 0;
  padding: 10px 12px;
  border-left: 4px solid var(--blue-500);
  border-radius: 0 6px 6px 0;
  background: rgba(255,255,255,.72);
  color: var(--blue-850);
  font-style: normal;
  font-weight: 700;
}

.dump{
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
  padding: 15px 18px;
}

.dump summary{
  cursor:pointer;
  color: var(--blue-700);
  font-weight:800;
}

.dump pre{
  margin: 14px 0 0;
  padding: 16px;
  overflow-x:auto;
  border-radius: 6px;
  background: var(--navy-950);
  color: var(--sky-100);
  font-family:'IBM Plex Mono', monospace;
  font-size:.78rem;
  line-height:1.6;
}

.table-wrap{
  overflow-x:auto;
  border: 1px solid var(--line);
  border-radius: 6px;
  background: var(--panel);
  box-shadow: 0 14px 32px rgba(15,74,145,.10);
}

.ledger{
  width:100%;
  min-width:640px;
  border-collapse:collapse;
  font-size:.88rem;
}

.ledger th{
  padding: 14px;
  text-align:left;
  background: var(--blue-850);
  color: var(--sky-50);
  font-size:.72rem;
  font-weight:800;
  text-transform:uppercase;
  letter-spacing:.08em;
}

.ledger td{
  padding: 12px 14px;
  border-bottom: 1px solid var(--line);
  color: #1b2b3f;
}

.ledger tbody tr:nth-child(even){
  background: var(--sky-50);
}

.ledger tbody tr:hover{
  background: var(--sky-100);
}

.table-note{
  margin: 12px 0 0;
  color: var(--muted);
  font-size:.84rem;
  font-style:italic;
}

.loading{
  display:flex;
  align-items:center;
  gap: 12px;
  min-height: 140px;
  color: var(--blue-700);
  font-weight:800;
}

.loading::before{
  content:"";
  width: 16px;
  height: 16px;
  border-radius: 50%;
  border: 3px solid var(--sky-200);
  border-top-color: var(--blue-600);
  animation: spin .8s linear infinite;
}

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

.table-picker-btn{
  min-height: 44px;
  border: none;
  border-radius: 6px;
  background: linear-gradient(135deg, var(--blue-600), var(--blue-500));
  color:#fff;
  cursor:pointer;
  font:inherit;
  font-weight:800;
  padding: 0 16px;
  white-space:nowrap;
  box-shadow: 0 10px 20px rgba(31,122,224,.24);
  transition: transform .16s ease, box-shadow .16s ease;
}

.table-picker-btn:hover{
  transform: translateY(-1px);
  box-shadow: 0 14px 24px rgba(31,122,224,.30);
}

.table-picker-btn:active{
  transform: translateY(0);
}

.table-picker-btn .current-table{
  color: #d8efff;
  font-weight:600;
}

dialog.table-modal{
  width:min(520px, calc(100% - 34px));
  max-width:520px;
  border:none;
  border-radius: 6px;
  padding:0;
  background:transparent;
}

dialog.table-modal::backdrop{
  background: rgba(3,17,31,.68);
}

.modal-card{
  overflow:hidden;
  border-radius:6px;
  background:#fff;
  box-shadow: 0 28px 64px rgba(3,17,31,.42);
}

.modal-head{
  display:flex;
  align-items:center;
  justify-content:space-between;
  gap:16px;
  padding:18px 20px;
  background: var(--blue-850);
  color:#fff;
}

.modal-head h3{
  margin:0;
  font-size:1rem;
}

.modal-close{
  display:grid;
  place-items:center;
  width:34px;
  height:34px;
  border:1px solid rgba(255,255,255,.24);
  border-radius:6px;
  background:rgba(255,255,255,.08);
  color:#fff;
  cursor:pointer;
  font-size:1.35rem;
  line-height:1;
}

.modal-close:hover{
  background:rgba(255,255,255,.16);
}

.modal-options{
  display:grid;
  grid-template-columns: repeat(2, 1fr);
  gap:10px;
  padding:18px 20px 22px;
}

.table-option{
  min-height:44px;
  border:1px solid var(--line);
  border-radius:6px;
  background:var(--panel-soft);
  color:var(--blue-850);
  cursor:pointer;
  font:inherit;
  font-size:.88rem;
  font-weight:800;
  text-align:left;
  padding:0 14px;
  transition: background .15s ease, border-color .15s ease, color .15s ease, transform .12s ease;
}

.table-option:hover{
  transform: translateY(-1px);
  border-color: rgba(31,122,224,.35);
  background: var(--sky-50);
}

.table-option.active{
  background: var(--blue-600);
  border-color: var(--blue-600);
  color:#fff;
}

.site-footer{
  position: relative;
  display:grid;
  grid-template-columns: 1fr auto;
  align-items:center;
  gap:18px;
  padding:22px clamp(18px, 5vw, 56px);
  background:
    linear-gradient(135deg, rgba(3,17,31,.98), rgba(9,46,93,.96)),
    var(--navy-950);
  border-top: 1px solid rgba(255,255,255,.12);
  overflow:hidden;
}

.site-footer::before{
  content:"";
  position:absolute;
  left: clamp(18px, 5vw, 56px);
  right: clamp(18px, 5vw, 56px);
  top: 0;
  height: 4px;
  background: linear-gradient(90deg, var(--aqua), var(--blue-500), transparent);
}

.site-footer::after{
  content:"";
  position:absolute;
  width: 170px;
  height: 170px;
  right: -64px;
  bottom: -112px;
  border: 28px solid rgba(55,199,212,.14);
  border-radius: 50%;
  pointer-events:none;
}

.footer-label{
  position:relative;
  z-index:1;
  margin:0;
  color: rgba(238,247,255,.64);
  font-size:.72rem;
  font-weight:800;
  letter-spacing:.18em;
  text-transform:uppercase;
}

.instructor-name{
  position:relative;
  z-index:1;
  margin:0;
  padding: 10px 14px;
  border: 1px solid rgba(238,247,255,.22);
  border-radius: 6px;
  background: rgba(255,255,255,.08);
  color:#ffffff;
  font-weight:800;
  box-shadow: inset 0 0 0 1px rgba(255,255,255,.04);
}

@media (max-width: 720px){
  body{
    padding: 16px 10px 34px;
  }

  .tabs{
    flex-direction:column;
    padding:0;
  }

  .tab{
    width:100%;
    text-align:left;
    border-bottom-width:1px;
    border-bottom-color: var(--line);
  }

  .tab[aria-selected="true"]{
    border-left: 4px solid var(--blue-500);
    border-bottom-color: var(--line);
  }

  .sheet-head{
    grid-template-columns: auto minmax(0, 1fr);
    align-items:start;
  }

  .sheet[data-sheet="1.1"] .records{
    grid-template-columns: 1fr;
  }

  .sheet[data-sheet="1.2"] .sheet-head{
    grid-template-columns: auto minmax(0, 1fr);
  }

  .table-picker-btn{
    grid-column: 1 / -1;
    width:100%;
  }

  .modal-options{
    grid-template-columns:1fr;
  }

  .site-footer{
    grid-template-columns: 1fr;
    align-items:flex-start;
  }
}