/* ==========================================================================
   GradingPad — Tactile Ivy Desk & Vintage Slide-Chart Design System
   Crafted with frontend-design + ui-ux-pro-max + modern-web-guidance
   ========================================================================== */

:root {
  color-scheme: light dark;

  --gp-paper: light-dark(#FAF7F2, #171614);
  --gp-card: light-dark(#FFFFFF, #211F1C);
  --gp-well: light-dark(#F2EDE4, #2A2723);
  --gp-well-hover: light-dark(#EAE3D6, #332F2A);
  --gp-border: light-dark(#E2DACB, #38342E);
  --gp-border-strong: light-dark(#C8BEA8, #4E483F);
  --gp-ink: light-dark(#17211C, #F2ECE1);
  --gp-muted: light-dark(#525E57, #AEA597);
  --gp-pine: light-dark(#16382C, #2E7059);
  --gp-pine-ink: #FFFFFF;
  --gp-pine-soft: light-dark(#E7F2ED, rgba(46, 112, 89, 0.18));
  --gp-vermilion: light-dark(#D94E34, #F06A50);
  --gp-vermilion-soft: light-dark(#FDF0ED, rgba(240, 106, 80, 0.15));
  --gp-lip: light-dark(#D3C9B6, #0E0D0C);
  --gp-dot: light-dark(rgba(23, 33, 28, 0.065), rgba(242, 236, 225, 0.055));

  /* Grade Semantic Badges */
  --grade-a-bg: light-dark(#E6F4EC, rgba(34, 197, 94, 0.18));
  --grade-a-fg: light-dark(#115E38, #6EE7B7);
  --grade-b-bg: light-dark(#E8F1FA, rgba(59, 130, 246, 0.18));
  --grade-b-fg: light-dark(#1D4ED8, #93C5FD);
  --grade-c-bg: light-dark(#FEF4E2, rgba(245, 158, 11, 0.18));
  --grade-c-fg: light-dark(#B45309, #FCD34D);
  --grade-d-bg: light-dark(#FDECE7, rgba(249, 115, 22, 0.18));
  --grade-d-fg: light-dark(#C2410C, #FDBA74);
  --grade-f-bg: light-dark(#FCE8E8, rgba(239, 68, 68, 0.18));
  --grade-f-fg: light-dark(#B91C1C, #FCA5A5);

  --font-serif: 'Fraunces', Georgia, 'Iowan Old Style', 'Times New Roman', serif;
  --font-sans: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
}

:root:has(> head > meta[name="color-scheme"][content="dark"]) {
  color-scheme: dark;
}
:root:has(> head > meta[name="color-scheme"][content="light"]) {
  color-scheme: light;
}

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

html {
  scroll-behavior: smooth;
  font-size: 16px;
}

@media (prefers-reduced-motion: reduce) {
  html { scroll-behavior: auto; }
  *, *::before, *::after {
    animation-duration: 0.01ms !important;
    transition-duration: 0.01ms !important;
  }
}

body {
  margin: 0;
  background-color: var(--gp-paper);
  background-image: radial-gradient(var(--gp-dot) 1px, transparent 1px);
  background-size: 20px 20px;
  color: var(--gp-ink);
  font-family: var(--font-sans);
  line-height: 1.65;
  -webkit-font-smoothing: antialiased;
}

a {
  color: var(--gp-pine);
  text-decoration: underline;
  text-underline-offset: 3px;
  text-decoration-thickness: 1.5px;
  transition: color 0.18s ease;
}
a:hover {
  color: var(--gp-vermilion);
}

.container {
  max-width: 1180px;
  margin-inline: auto;
  padding-inline: 16px;
}
@media (min-width: 640px) {
  .container { padding-inline: 24px; }
}
@media (min-width: 1024px) {
  .container { padding-inline: 32px; }
}

/* Floating Tactile Stationery Header */
.site-header-wrap {
  padding-block: 14px 6px;
  position: sticky;
  top: 0;
  z-index: 40;
}

.site-header {
  background: var(--gp-card);
  border: 1px solid var(--gp-border);
  border-radius: 18px;
  padding: 10px 16px;
  box-shadow: 0 10px 28px -14px rgba(23, 33, 28, 0.14), 0 2px 0 0 var(--gp-border);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  flex-wrap: wrap;
}

.brand-link {
  display: inline-flex;
  align-items: center;
  gap: 10px;
  text-decoration: none;
  color: var(--gp-ink);
}
.brand-link:hover { color: var(--gp-ink); }

.brand-icon {
  width: 36px;
  height: 36px;
  border-radius: 11px;
  background: var(--gp-pine);
  color: #FFFFFF;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
}

.brand-title {
  font-family: var(--font-serif);
  font-weight: 700;
  font-size: 1.2rem;
  letter-spacing: -0.025em;
}

.brand-tag {
  font-size: 0.75rem;
  font-weight: 600;
  padding: 2px 8px;
  border-radius: 999px;
  background: var(--gp-well);
  color: var(--gp-muted);
  border: 1px solid var(--gp-border);
}

.nav-pills {
  display: flex;
  align-items: center;
  gap: 4px;
  background: var(--gp-well);
  padding: 4px;
  border-radius: 12px;
  border: 1px solid var(--gp-border);
  flex-wrap: wrap;
}

.nav-pills a {
  text-decoration: none;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--gp-muted);
  padding: 6px 11px;
  border-radius: 9px;
  transition: background-color 0.16s ease, color 0.16s ease;
  white-space: nowrap;
}
.nav-pills a:hover {
  color: var(--gp-ink);
  background: var(--gp-card);
}
.nav-pills a.active {
  background: var(--gp-pine);
  color: #FFFFFF;
}

/* Tactile Keycap Buttons */
.keycap {
  appearance: none;
  background: var(--gp-card);
  border: 1px solid var(--gp-border-strong);
  box-shadow: 0 2px 0 0 var(--gp-lip);
  color: var(--gp-ink);
  border-radius: 11px;
  font-family: var(--font-sans);
  font-size: 0.8125rem;
  font-weight: 700;
  padding: 8px 12px;
  min-height: 40px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 6px;
  cursor: pointer;
  user-select: none;
  text-decoration: none;
  transition: transform 0.12s ease, box-shadow 0.12s ease, background-color 0.15s ease, border-color 0.15s ease;
}
.keycap:hover {
  background: var(--gp-well);
  border-color: var(--gp-pine);
}
.keycap:focus-visible, input:focus-visible, select:focus-visible, textarea:focus-visible, summary:focus-visible {
  outline: 2.5px solid var(--gp-vermilion);
  outline-offset: 2px;
}
.keycap:active, .keycap.is-active {
  transform: translateY(1px);
  box-shadow: 0 1px 0 0 var(--gp-lip);
}
.keycap.is-active {
  background: var(--gp-pine);
  border-color: var(--gp-pine);
  color: #FFFFFF;
}

.btn-primary {
  appearance: none;
  background: var(--gp-pine);
  color: #FFFFFF;
  border: 1px solid var(--gp-pine);
  box-shadow: 0 2px 0 0 #0D231B;
  border-radius: 12px;
  font-family: var(--font-sans);
  font-weight: 700;
  font-size: 0.875rem;
  padding: 11px 16px;
  min-height: 44px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  cursor: pointer;
  transition: opacity 0.16s ease, transform 0.12s ease;
  text-decoration: none;
}
.btn-primary:hover {
  opacity: 0.94;
  color: #FFFFFF;
}
.btn-primary:active {
  transform: translateY(1px);
}

/* Hero Section */
.hero-header {
  margin-block: 20px 18px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}
@media (min-width: 768px) {
  .hero-header {
    flex-direction: row;
    align-items: flex-end;
    justify-content: space-between;
  }
}

.eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--gp-vermilion);
  margin-bottom: 4px;
}
.eyebrow-dot {
  width: 8px;
  height: 8px;
  border-radius: 999px;
  background: var(--gp-vermilion);
}

h1 {
  font-family: var(--font-serif);
  font-size: clamp(1.9rem, 3.6vw, 2.65rem);
  line-height: 1.15;
  letter-spacing: -0.025em;
  margin: 0;
  color: var(--gp-ink);
}

.hero-sub {
  margin: 6px 0 0;
  color: var(--gp-muted);
  font-size: 0.975rem;
  max-width: 68ch;
}

.trust-pill {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 13px;
  border-radius: 12px;
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--gp-muted);
  flex-shrink: 0;
}

/* 12-Col Asymmetric Desk Workspace */
.desk-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 22px;
  align-items: start;
}
@media (min-width: 980px) {
  .desk-grid {
    grid-template-columns: minmax(0, 5fr) minmax(0, 7fr);
  }
}

.gp-card {
  background: var(--gp-card);
  border: 1px solid var(--gp-border);
  border-radius: 20px;
  padding: 20px;
  box-shadow: 0 12px 32px -14px rgba(23, 33, 28, 0.09), 0 2px 0 0 var(--gp-border);
}
@media (min-width: 640px) {
  .gp-card { padding: 24px; }
}

.gp-well {
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 16px;
}

/* Red-Pen Score Readout */
.score-banner {
  padding: 18px 20px;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  margin-bottom: 18px;
}

.score-label {
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--gp-muted);
}

.score-big {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: clamp(2.15rem, 4.5vw, 3rem);
  font-weight: 800;
  line-height: 1.05;
  letter-spacing: -0.03em;
  margin-top: 2px;
}

.score-meta {
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.8125rem;
  font-weight: 600;
  color: var(--gp-muted);
  margin-top: 6px;
}

.red-pen-stamp {
  width: 84px;
  height: 84px;
  border-radius: 999px;
  border: 2.5px solid var(--gp-vermilion);
  background: var(--gp-vermilion-soft);
  color: var(--gp-vermilion);
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  transform: rotate(-4deg);
  box-shadow: inset 0 0 0 2px var(--gp-card);
  flex-shrink: 0;
  user-select: none;
}

.stamp-letter {
  font-family: var(--font-serif);
  font-size: 1.9rem;
  font-weight: 900;
  line-height: 1;
}

.stamp-gpa {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  font-weight: 700;
  margin-top: 3px;
}

/* Controls & Form Fields */
.field-block {
  margin-bottom: 16px;
}

.field-head {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 8px;
  margin-bottom: 8px;
}

.field-label {
  font-size: 0.78rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--gp-muted);
}

.stepper-row {
  display: grid;
  grid-template-columns: 44px 1fr 44px;
  gap: 8px;
  align-items: center;
}

.num-input, .text-input, .select-input {
  width: 100%;
  min-height: 44px;
  border-radius: 12px;
  border: 1px solid var(--gp-border-strong);
  background: var(--gp-well);
  color: var(--gp-ink);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 1.25rem;
  font-weight: 700;
  text-align: center;
  padding: 6px 12px;
}

.text-input, .select-input {
  font-family: var(--font-sans);
  font-size: 0.9rem;
  font-weight: 600;
  text-align: left;
}

.preset-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 6px;
  margin-top: 9px;
}
@media (min-width: 480px) {
  .preset-grid { grid-template-columns: repeat(8, 1fr); }
}
.preset-grid .keycap {
  font-family: var(--font-mono);
  padding: 6px 4px;
  min-height: 36px;
  font-size: 0.78rem;
}

.range-slider {
  width: 100%;
  margin-top: 10px;
  accent-color: var(--gp-pine);
  cursor: pointer;
}

.split-2 {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  padding-top: 14px;
  border-top: 1px solid var(--gp-border);
}
@media (min-width: 520px) {
  .split-2 { grid-template-columns: 1fr 1fr; }
}

/* Interactive Slide-Chart Grid */
.chart-toolbar {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  justify-content: space-between;
  gap: 10px;
  padding-bottom: 14px;
  margin-bottom: 14px;
  border-bottom: 1px solid var(--gp-border);
}

.chart-columns {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  max-height: 490px;
  overflow-y: auto;
  padding-right: 4px;
}
@media (min-width: 580px) {
  .chart-columns { grid-template-columns: 1fr 1fr; }
}

.chart-col-box {
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 14px;
  overflow: hidden;
}

.chart-row {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 8px 12px;
  border-bottom: 1px solid var(--gp-border);
  font-family: var(--font-mono);
  font-variant-numeric: tabular-nums;
  font-size: 0.8125rem;
  cursor: pointer;
  transition: background-color 0.14s ease;
}
.chart-row:last-child { border-bottom: none; }
.chart-row:hover { background: var(--gp-well-hover); }
.chart-row.is-current {
  background: var(--gp-vermilion-soft);
  border-left: 3.5px solid var(--gp-vermilion);
  font-weight: 700;
}

.grade-pill {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  min-width: 36px;
  padding: 2px 7px;
  border-radius: 7px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 800;
}
.grade-a { background: var(--grade-a-bg); color: var(--grade-a-fg); }
.grade-b { background: var(--grade-b-bg); color: var(--grade-b-fg); }
.grade-c { background: var(--grade-c-bg); color: var(--grade-c-fg); }
.grade-d { background: var(--grade-d-bg); color: var(--grade-d-fg); }
.grade-f { background: var(--grade-f-bg); color: var(--grade-f-fg); }

/* Searchable Hidden Drawer (modern-web-guidance: search-hidden-content) */
.drawer-inner {
  margin-top: 14px;
  padding: 16px;
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 14px;
}

.roster-chips {
  display: flex;
  flex-wrap: wrap;
  gap: 6px;
  margin-top: 10px;
}
.roster-chip {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  font-weight: 700;
  padding: 4px 9px;
  border-radius: 8px;
  background: var(--gp-card);
  border: 1px solid var(--gp-border);
}

/* Editorial Content Sections */
.content-section {
  margin-top: 44px;
}

.section-card {
  background: var(--gp-card);
  border: 1px solid var(--gp-border);
  border-radius: 20px;
  padding: 26px 22px;
  box-shadow: 0 8px 24px -14px rgba(23, 33, 28, 0.07);
}
@media (min-width: 768px) {
  .section-card { padding: 34px 36px; }
}

h2 {
  font-family: var(--font-serif);
  font-size: clamp(1.4rem, 2.5vw, 1.85rem);
  line-height: 1.25;
  letter-spacing: -0.02em;
  margin: 0 0 14px;
  color: var(--gp-ink);
}

h3 {
  font-family: var(--font-serif);
  font-size: 1.15rem;
  line-height: 1.35;
  margin: 0 0 8px;
  color: var(--gp-ink);
}

p {
  margin: 0 0 14px;
  color: var(--gp-ink);
  max-width: 75ch;
}
p.muted { color: var(--gp-muted); }

.bento-3 {
  display: grid;
  grid-template-columns: 1fr;
  gap: 16px;
  margin-top: 18px;
}
@media (min-width: 768px) {
  .bento-3 { grid-template-columns: repeat(3, 1fr); }
}

.bento-item {
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 16px;
  padding: 20px;
}

.step-num {
  width: 32px;
  height: 32px;
  border-radius: 9px;
  background: var(--gp-pine);
  color: #FFFFFF;
  font-family: var(--font-mono);
  font-weight: 800;
  font-size: 0.85rem;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 12px;
}

.formula-box {
  font-family: var(--font-mono);
  font-size: 0.9rem;
  background: var(--gp-well);
  border-left: 4px solid var(--gp-pine);
  padding: 14px 18px;
  border-radius: 10px;
  margin-block: 16px;
  overflow-x: auto;
}

/* Responsive Data Table (modern-web-guidance: responsive-table) */
.table-wrapper {
  overflow: auto;
  max-inline-size: 100%;
  max-block-size: min(520px, 80vh);
  container-type: inline-size;
  border: 1px solid var(--gp-border);
  border-radius: 14px;
  background: var(--gp-card);
  margin-top: 16px;
}

.data-table {
  width: 100%;
  border-collapse: separate;
  border-spacing: 0;
  font-size: 0.9rem;
}

.data-table caption {
  text-align: left;
  padding: 12px 16px;
  font-weight: 700;
  font-size: 0.85rem;
  color: var(--gp-muted);
  background: var(--gp-well);
  border-bottom: 1px solid var(--gp-border);
}

.data-table thead {
  position: sticky;
  inset-block-start: 0;
  z-index: 2;
  background: var(--gp-well);
}

.data-table th, .data-table td {
  padding: 11px 15px;
  text-align: left;
  border-bottom: 1px solid var(--gp-border);
}

.data-table thead th {
  font-size: 0.78rem;
  text-transform: uppercase;
  letter-spacing: 0.05em;
  color: var(--gp-muted);
  font-weight: 800;
}

.data-table tbody th {
  position: sticky;
  inset-inline-start: 0;
  z-index: 1;
  background: var(--gp-card);
  font-family: var(--font-mono);
  font-weight: 700;
}

@container (width < 560px) {
  .data-table, .data-table thead, .data-table tbody, .data-table tr, .data-table th, .data-table td {
    display: block;
  }
  .data-table thead {
    display: none;
  }
  .data-table tr {
    margin: 10px;
    border: 1px solid var(--gp-border);
    border-radius: 12px;
    overflow: hidden;
  }
  .data-table tbody th {
    position: sticky;
    inset-block-start: 0;
    background: var(--gp-well);
  }
  .data-table td:nth-child(2)::before { content: var(--label-2, "Detail") ": "; font-weight: 700; color: var(--gp-muted); }
  .data-table td:nth-child(3)::before { content: var(--label-3, "Scale") ": "; font-weight: 700; color: var(--gp-muted); }
  .data-table td:nth-child(4)::before { content: var(--label-4, "GPA") ": "; font-weight: 700; color: var(--gp-muted); }
}

/* Exclusive Accessible FAQ Accordions (<details name="gp-faq">) */
.faq-list {
  display: grid;
  gap: 10px;
  margin-top: 16px;
}

.faq-card {
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 14px;
  overflow: hidden;
}

.faq-card summary {
  padding: 15px 18px;
  font-weight: 700;
  font-size: 0.98rem;
  cursor: pointer;
  list-style: none;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
}
.faq-card summary::-webkit-details-marker { display: none; }
.faq-card summary::after {
  content: "+";
  font-family: var(--font-mono);
  font-size: 1.2rem;
  font-weight: 700;
  color: var(--gp-pine);
  flex-shrink: 0;
}
.faq-card[open] summary::after {
  content: "−";
  color: var(--gp-vermilion);
}
.faq-body {
  padding: 0 18px 16px;
  color: var(--gp-muted);
  font-size: 0.94rem;
}

/* Tool Suite Cross-Links */
.suite-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
  margin-top: 16px;
}
@media (min-width: 640px) {
  .suite-grid { grid-template-columns: repeat(2, 1fr); }
}
@media (min-width: 980px) {
  .suite-grid { grid-template-columns: repeat(4, 1fr); }
}

.suite-card {
  display: block;
  text-decoration: none;
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 15px;
  padding: 16px;
  color: var(--gp-ink);
  transition: border-color 0.16s ease, background-color 0.16s ease;
}
.suite-card:hover {
  border-color: var(--gp-pine);
  background: var(--gp-card);
  color: var(--gp-ink);
}
.suite-card strong {
  display: block;
  font-family: var(--font-serif);
  font-size: 1.05rem;
  margin-bottom: 4px;
}
.suite-card span {
  font-size: 0.82rem;
  color: var(--gp-muted);
}

/* Group Maker Cards */
.groups-output {
  display: grid;
  grid-template-columns: 1fr;
  gap: 12px;
}
@media (min-width: 600px) {
  .groups-output { grid-template-columns: repeat(2, 1fr); }
}
.group-box {
  background: var(--gp-well);
  border: 1px solid var(--gp-border);
  border-radius: 14px;
  padding: 14px 16px;
}
.group-box h3 {
  font-size: 0.95rem;
  margin-bottom: 8px;
  color: var(--gp-pine);
}
.group-box ul {
  margin: 0;
  padding-left: 18px;
  font-size: 0.88rem;
}

/* Site Footer */
.site-footer {
  margin-top: 56px;
  padding-block: 32px 44px;
  border-top: 1px solid var(--gp-border);
  font-size: 0.85rem;
  color: var(--gp-muted);
}
.footer-inner {
  display: flex;
  flex-wrap: wrap;
  justify-content: space-between;
  gap: 20px;
}
.footer-links {
  display: flex;
  flex-wrap: wrap;
  gap: 14px;
}


/* Tactile Ivy Desk Non-Intrusive AdSense Container (Zero CLS, Hidden on Print) */
.gp-ad-slot {
  margin-block: 24px 8px;
  padding: 14px 18px;
  border-radius: 16px;
  background: var(--gp-well);
  border: 1px dashed var(--gp-border-strong);
  text-align: center;
  contain: layout style;
}
.gp-ad-slot[hidden] {
  display: none !important;
}
.gp-ad-label {
  display: block;
  font-size: 0.68rem;
  font-weight: 700;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--gp-muted);
  margin-bottom: 8px;
}
.gp-ad-inner {
  min-height: 90px;
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
}

/* Clean Classroom Desk Print View */
@media print {
  .site-header-wrap, .content-section, .site-footer, .no-print {
    display: none !important;
  }
  body {
    background: #FFFFFF !important;
    color: #000000 !important;
  }
  .desk-grid {
    display: block !important;
  }
  .chart-columns {
    max-height: none !important;
    overflow: visible !important;
    grid-template-columns: 1fr 1fr !important;
  }
  .gp-card {
    box-shadow: none !important;
    border: 1px solid #CCCCCC !important;
  }
}