@import url("https://fonts.googleapis.com/css2?family=Fraunces:ital,opsz,wght@0,9..144,400;0,9..144,600;0,9..144,700;1,9..144,500&family=Inter:wght@400;500;600;700&family=IBM+Plex+Mono:wght@400;500;600&family=Tiro+Bangla&display=swap");

:root {
  /* Color tokens -- warm exercise-book paper, NCTB-cover green, red-pen maroon */
  --paper: #f4eedd;
  --paper-deep: #ece2c8;
  --paper-line: #ddceac;
  --ink: #24312b;
  --ink-soft: #57614f;
  --green: #0b6e4f;
  --green-deep: #084c37;
  --green-tint: #e4efe6;
  --maroon: #a6332b;
  --maroon-tint: #f6e6e2;
  --gold: #c99a3e;
  --white: #fffdf7;

  --font-display: "Fraunces", "Tiro Bangla", serif;
  --font-body: "Inter", "Tiro Bangla", system-ui, sans-serif;
  --font-mono: "IBM Plex Mono", monospace;

  --radius: 3px;
  --shadow-page: 0 18px 40px -20px rgba(8, 40, 28, 0.35);
}

* {
  box-sizing: border-box;
}

html,
body {
  height: 100%;
}

body {
  margin: 0;
  background-color: var(--paper-deep);
  background-image: radial-gradient(rgba(36, 49, 43, 0.055) 1px, transparent 1px);
  background-size: 14px 14px;
  color: var(--ink);
  font-family: var(--font-body);
  -webkit-font-smoothing: antialiased;
}

button {
  font-family: inherit;
}

/* Reduced motion respected */
@media (prefers-reduced-motion: reduce) {
  * {
    animation-duration: 0.001ms !important;
    transition-duration: 0.001ms !important;
  }
}

/* ---------------------------------------------------------------------- */
/* App shell                                                               */
/* ---------------------------------------------------------------------- */

.app-shell {
  display: grid;
  grid-template-columns: 300px 1fr;
  min-height: 100vh;
}

@media (max-width: 860px) {
  .app-shell {
    grid-template-columns: 1fr;
  }

  .spine::after {
    display: none;
  }

  .mode-tabs {
    flex-direction: row;
    overflow-x: auto;
    padding-bottom: 4px;
  }

  .mode-tab {
    flex: 1 0 auto;
  }

  .mode-tab .mode-tab-text {
    white-space: nowrap;
  }
}

/* ---------------------------------------------------------------------- */
/* Sidebar / "book spine"                                                  */
/* ---------------------------------------------------------------------- */

.spine {
  background: linear-gradient(180deg, var(--green-deep), var(--green) 70%);
  color: var(--white);
  padding: 28px 22px 22px;
  position: sticky;
  top: 0;
  align-self: start;
  height: 100vh;
  overflow-y: auto;
}

@media (max-width: 860px) {
  .spine {
    position: static;
    height: auto;
  }
}

.spine::after {
  /* gold foil edge, like a book cover's stamped border */
  content: "";
  position: absolute;
  inset: 10px;
  border: 1px solid rgba(201, 154, 62, 0.45);
  pointer-events: none;
}

.brand {
  margin-bottom: 18px;
}

.brand-mark {
  margin-bottom: 12px;
  filter: drop-shadow(0 2px 3px rgba(0, 0, 0, 0.25));
}

.brand-eyebrow {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.14em;
  text-transform: uppercase;
  color: var(--gold);
  display: block;
  margin-bottom: 6px;
}

.brand-title {
  font-family: var(--font-display);
  font-size: 24px;
  line-height: 1.15;
  font-weight: 600;
  margin: 0;
}

.brand-title .bn {
  font-family: "Tiro Bangla", serif;
  display: block;
  font-size: 17px;
  font-weight: 400;
  color: rgba(255, 253, 247, 0.75);
  margin-top: 4px;
}

/* Selection progress dots */
.progress-dots {
  display: flex;
  gap: 14px;
  margin-bottom: 24px;
  padding-bottom: 18px;
  border-bottom: 1px solid rgba(255, 253, 247, 0.15);
}

.progress-dot {
  display: flex;
  align-items: center;
  gap: 6px;
  font-family: var(--font-mono);
  font-size: 10px;
  letter-spacing: 0.04em;
  color: rgba(255, 253, 247, 0.45);
  transition: color 0.25s ease;
}

.progress-dot span {
  width: 7px;
  height: 7px;
  border-radius: 50%;
  border: 1.4px solid rgba(255, 253, 247, 0.45);
  background: transparent;
  transition: background 0.25s ease, border-color 0.25s ease, transform 0.25s ease;
}

.progress-dot.is-done {
  color: var(--gold);
}

.progress-dot.is-done span {
  background: var(--gold);
  border-color: var(--gold);
  transform: scale(1.15);
}

.spine-section {
  margin-bottom: 20px;
}

.spine-label {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: rgba(255, 253, 247, 0.6);
  display: block;
  margin-bottom: 8px;
}

.spine-select {
  width: 100%;
  appearance: none;
  background-color: rgba(255, 253, 247, 0.08);
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%23C99A3E' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 12px center;
  border: 1px solid rgba(255, 253, 247, 0.25);
  color: var(--white);
  font-family: var(--font-body);
  font-size: 14.5px;
  padding: 10px 30px 10px 12px;
  border-radius: var(--radius);
  cursor: pointer;
  transition: border-color 0.15s ease, background-color 0.15s ease;
}

.spine-select:hover:not(:disabled) {
  border-color: rgba(201, 154, 62, 0.6);
}

.spine-select:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.spine-select:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

.spine-select option {
  /* The dropdown popup is rendered by the browser with a light background,
     independent of the select's own (dark) styling — so options need their
     own dark-on-light colors or they become invisible white-on-white. */
  color: var(--ink);
  background: var(--white);
}

/* Mode tabs styled as bookmark tabs */
.mode-tabs {
  display: flex;
  flex-direction: column;
  gap: 8px;
  margin-top: 4px;
}

.mode-tab {
  display: flex;
  align-items: center;
  gap: 10px;
  background: rgba(255, 253, 247, 0.06);
  border: 1px solid rgba(255, 253, 247, 0.18);
  border-left: 3px solid transparent;
  color: rgba(255, 253, 247, 0.85);
  text-align: left;
  padding: 11px 12px;
  border-radius: var(--radius);
  font-size: 14px;
  cursor: pointer;
  transition: background 0.15s ease, border-color 0.15s ease, transform 0.15s ease;
}

.mode-tab:hover {
  background: rgba(255, 253, 247, 0.12);
  transform: translateX(2px);
}

.mode-tab:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

.mode-tab .mode-icon {
  flex-shrink: 0;
  opacity: 0.8;
  transition: opacity 0.15s ease, transform 0.2s ease;
}

.mode-tab[aria-pressed="true"] {
  background: var(--gold);
  border-left-color: var(--white);
  color: var(--green-deep);
  font-weight: 600;
  transform: translateX(3px);
  box-shadow: 0 4px 10px -4px rgba(0, 0, 0, 0.4);
}

.mode-tab[aria-pressed="true"] .mode-icon {
  opacity: 1;
  transform: scale(1.08);
}

.mode-tab .bn {
  font-family: "Tiro Bangla", serif;
  font-size: 12.5px;
  opacity: 0.75;
}

.spine-footer {
  margin-top: 28px;
  padding-top: 16px;
  border-top: 1px solid rgba(255, 253, 247, 0.18);
  font-size: 12px;
  color: rgba(255, 253, 247, 0.55);
  line-height: 1.5;
}

/* ---------------------------------------------------------------------- */
/* Main "notebook page"                                                    */
/* ---------------------------------------------------------------------- */

.page-wrap {
  padding: 40px 48px;
  display: flex;
  justify-content: center;
  position: relative;
}

.page-wrap::before {
  /* soft vignette behind the page for depth */
  content: "";
  position: absolute;
  inset: 0;
  background: radial-gradient(ellipse 60% 45% at 50% 30%, rgba(8, 76, 55, 0.08), transparent 70%);
  pointer-events: none;
}

@media (max-width: 640px) {
  .page-wrap {
    padding: 20px 16px;
  }
}

.notebook-page {
  width: 100%;
  max-width: 760px;
  background: repeating-linear-gradient(
    var(--paper),
    var(--paper) 33px,
    var(--paper-line) 34px
  );
  background-color: var(--paper);
  border-radius: var(--radius);
  box-shadow: var(--shadow-page), 0 1px 0 rgba(255, 255, 255, 0.6) inset;
  position: relative;
  padding: 36px 40px 40px 64px;
  min-height: 520px;
  overflow: hidden;
}

.page-fold {
  position: absolute;
  top: 0;
  right: 0;
  width: 34px;
  height: 34px;
  background: linear-gradient(135deg, var(--white) 48%, var(--paper-line) 50%);
  clip-path: polygon(100% 0, 0 0, 100% 100%);
  box-shadow: -3px 3px 6px -2px rgba(36, 49, 43, 0.35);
  z-index: 2;
}

.notebook-page::before {
  /* the red margin rule */
  content: "";
  position: absolute;
  top: 0;
  bottom: 0;
  left: 44px;
  width: 1.5px;
  background: rgba(166, 51, 43, 0.45);
}

/* spiral binding dots along the left edge */
.notebook-page::after {
  content: "";
  position: absolute;
  top: 30px;
  bottom: 30px;
  left: -8px;
  width: 16px;
  background-image: radial-gradient(circle, var(--paper-deep) 3.5px, transparent 3.6px);
  background-size: 16px 28px;
  background-repeat: repeat-y;
}

.page-header {
  margin-bottom: 22px;
  animation: fadeUp 0.4s ease both;
}

.page-eyebrow {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.1em;
  text-transform: uppercase;
  color: var(--green);
  margin-bottom: 6px;
  display: block;
}

.page-title {
  font-family: var(--font-display);
  font-size: 26px;
  font-weight: 600;
  margin: 0 0 10px;
  color: var(--ink);
}

.breadcrumb {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 6px;
}

.breadcrumb-chip {
  font-size: 12.5px;
  color: var(--green-deep);
  background: var(--green-tint);
  border: 1px solid rgba(11, 110, 79, 0.2);
  padding: 3px 10px;
  border-radius: 20px;
}

.breadcrumb-sep {
  color: var(--paper-line);
  font-size: 12px;
}

#mode-body {
  animation: fadeUp 0.35s ease both;
}

/* Empty state / hero */
.empty-state {
  text-align: center;
  padding: 24px 8px 8px;
  color: var(--ink-soft);
  animation: fadeUp 0.5s ease both;
}

.empty-illustration {
  margin: 0 auto 18px;
  width: 120px;
  height: 90px;
}

.empty-state .eyebrow-tag {
  font-family: var(--font-mono);
  font-size: 10.5px;
  letter-spacing: 0.12em;
  text-transform: uppercase;
  color: var(--green);
  display: block;
  margin-bottom: 10px;
}

.empty-state h2 {
  font-family: var(--font-display);
  font-weight: 600;
  color: var(--ink);
  font-size: 25px;
  margin-bottom: 10px;
  line-height: 1.25;
}

.empty-state .empty-sub {
  font-size: 14.5px;
  max-width: 440px;
  margin: 0 auto 30px;
  line-height: 1.6;
}

.empty-state .empty-sub .bn {
  font-family: "Tiro Bangla", serif;
  display: block;
  margin-bottom: 6px;
  font-size: 14px;
}

.feature-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  text-align: left;
}

@media (max-width: 560px) {
  .feature-grid {
    grid-template-columns: 1fr;
  }
}

.feature-card {
  background: var(--white);
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  padding: 16px 15px;
  transition: transform 0.15s ease, box-shadow 0.15s ease, border-color 0.15s ease;
}

.feature-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 10px 20px -12px rgba(36, 49, 43, 0.35);
  border-color: var(--green);
}

.feature-card .feature-icon {
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--green-tint);
  color: var(--green-deep);
  display: flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 10px;
}

.feature-card h3 {
  font-family: var(--font-display);
  font-size: 14.5px;
  font-weight: 600;
  margin: 0 0 4px;
  color: var(--ink);
}

.feature-card p {
  font-size: 12.5px;
  color: var(--ink-soft);
  line-height: 1.5;
  margin: 0;
}

@keyframes fadeUp {
  from {
    opacity: 0;
    transform: translateY(8px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

/* Form elements inside the page */
.field {
  margin-bottom: 18px;
}

.field label {
  display: block;
  font-size: 12.5px;
  font-weight: 600;
  color: var(--ink-soft);
  margin-bottom: 6px;
  text-transform: uppercase;
  letter-spacing: 0.05em;
}

textarea,
select.field-select {
  width: 100%;
  font-family: var(--font-body);
  font-size: 15px;
  padding: 12px 14px;
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  background: var(--white);
  color: var(--ink);
  resize: vertical;
  transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

textarea:hover,
select.field-select:hover {
  border-color: #c9bd9a;
}

select.field-select {
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' fill='none' stroke='%230B6E4F' stroke-width='1.6' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 34px;
  cursor: pointer;
}

textarea:focus-visible,
select.field-select:focus-visible,
input:focus-visible {
  outline: 2px solid var(--green);
  outline-offset: 1px;
}

.btn {
  font-family: var(--font-body);
  font-weight: 600;
  font-size: 14.5px;
  padding: 11px 22px;
  border-radius: var(--radius);
  border: none;
  cursor: pointer;
  transition: transform 0.1s ease, box-shadow 0.15s ease;
}

.btn-primary {
  background: var(--green);
  color: var(--white);
  box-shadow: 0 2px 0 var(--green-deep);
}

.btn-primary:hover:not(:disabled) {
  background: var(--green-deep);
  transform: translateY(1px);
  box-shadow: 0 1px 0 var(--green-deep);
}

.btn-primary:active:not(:disabled) {
  transform: translateY(2px);
  box-shadow: none;
}

.btn-primary:disabled {
  background: var(--ink-soft);
  cursor: not-allowed;
  opacity: 0.6;
}

.btn-primary:focus-visible {
  outline: 2px solid var(--gold);
  outline-offset: 2px;
}

.btn-row {
  display: flex;
  gap: 10px;
  margin-top: 6px;
}

/* QA answer block */
.answer-block {
  background: var(--white);
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  padding: 18px 20px;
  margin-top: 18px;
}

.answer-block p {
  margin: 0 0 12px;
  line-height: 1.6;
  font-size: 15px;
}

.sources {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-top: 10px;
}

.source-chip {
  font-family: var(--font-mono);
  font-size: 11.5px;
  background: var(--green-tint);
  color: var(--green-deep);
  padding: 4px 9px;
  border-radius: 20px;
  border: 1px solid rgba(11, 110, 79, 0.25);
}

/* MCQ options */
.mcq-question {
  font-size: 16px;
  line-height: 1.55;
  margin-bottom: 16px;
}

.mcq-options {
  display: flex;
  flex-direction: column;
  gap: 9px;
  margin-bottom: 18px;
}

.mcq-option {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 11px 14px;
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  background: var(--white);
  cursor: pointer;
  font-size: 14.5px;
  transition: border-color 0.15s ease, background 0.15s ease, transform 0.1s ease;
  position: relative;
}

.mcq-option:hover {
  border-color: var(--green);
  transform: translateX(2px);
}

.mcq-option input {
  position: absolute;
  opacity: 0;
  width: 1px;
  height: 1px;
}

.mcq-option .option-badge {
  flex-shrink: 0;
  width: 26px;
  height: 26px;
  border-radius: 50%;
  border: 1.6px solid var(--paper-line);
  color: var(--ink-soft);
  font-family: var(--font-mono);
  font-size: 12px;
  font-weight: 600;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.15s ease;
}

.mcq-option input:checked + .option-badge {
  border-color: var(--green);
  background: var(--green);
  color: var(--white);
}

.mcq-option:has(input:focus-visible) {
  outline: 2px solid var(--green);
  outline-offset: 2px;
}

.mcq-option.is-correct {
  border-color: var(--green);
  background: var(--green-tint);
  animation: stampIn 0.35s ease both;
}

.mcq-option.is-correct .option-badge {
  border-color: var(--green);
  background: var(--green);
  color: var(--white);
}

.mcq-option.is-incorrect {
  border-color: var(--maroon);
  background: var(--maroon-tint);
  animation: shake 0.4s ease both;
}

.mcq-option.is-incorrect .option-badge {
  border-color: var(--maroon);
  background: var(--maroon);
  color: var(--white);
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-4px); }
  75% { transform: translateX(4px); }
}

/* CQ parts */
.cq-stimulus {
  background: var(--white);
  border: 1px solid var(--paper-line);
  border-radius: var(--radius);
  padding: 16px 18px;
  font-size: 14.5px;
  line-height: 1.6;
  margin-bottom: 20px;
  color: var(--ink-soft);
}

.cq-part {
  margin-bottom: 18px;
  animation: fadeUp 0.4s ease both;
}

.cq-part-head {
  display: flex;
  align-items: flex-start;
  gap: 12px;
  margin-bottom: 8px;
}

.cq-part-badge {
  flex-shrink: 0;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  border: 1.6px solid var(--paper-line);
  color: var(--ink-soft);
  font-family: "Tiro Bangla", serif;
  font-size: 14px;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1px;
}

.cq-part-label {
  font-family: var(--font-display);
  font-weight: 600;
  font-size: 15px;
  color: var(--ink);
  padding-top: 4px;
}

.char-count {
  font-family: var(--font-mono);
  font-size: 11px;
  color: var(--ink-soft);
  opacity: 0.6;
  text-align: right;
  margin-top: 4px;
}

/* ---- Signature element: red-pen grading feedback ---- */
.grade-report {
  margin-top: 26px;
  padding-top: 18px;
  border-top: 1.5px dashed var(--paper-line);
  animation: fadeUp 0.4s ease both;
}

.grade-report-title {
  font-family: var(--font-mono);
  font-size: 11px;
  letter-spacing: 0.08em;
  text-transform: uppercase;
  color: var(--ink-soft);
  margin-bottom: 14px;
}

.grade-part {
  display: grid;
  grid-template-columns: 44px 1fr;
  gap: 14px;
  align-items: start;
  margin-bottom: 14px;
}

.grade-score {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  border: 2px solid var(--maroon);
  color: var(--maroon);
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 15px;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: rotate(-6deg);
  animation: stampIn 0.4s cubic-bezier(0.34, 1.56, 0.64, 1) both;
}

.grade-part:nth-child(2) .grade-score { animation-delay: 0.05s; }
.grade-part:nth-child(3) .grade-score { animation-delay: 0.15s; }
.grade-part:nth-child(4) .grade-score { animation-delay: 0.25s; }
.grade-part:nth-child(5) .grade-score { animation-delay: 0.35s; }

@keyframes stampIn {
  0% {
    opacity: 0;
    transform: scale(1.8) rotate(-6deg);
  }
  60% {
    opacity: 1;
    transform: scale(0.92) rotate(-6deg);
  }
  100% {
    opacity: 1;
    transform: scale(1) rotate(-6deg);
  }
}

.grade-feedback {
  font-size: 13.5px;
  color: var(--ink-soft);
  padding-top: 4px;
  font-style: italic;
}

.grade-feedback::before {
  content: "\2014 ";
  color: var(--maroon);
}

.grade-total {
  margin-top: 8px;
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 18px;
  color: var(--maroon);
}

.grade-total .grade-total-badge {
  border: 2.5px solid var(--maroon);
  border-radius: 50%;
  width: 56px;
  height: 56px;
  display: flex;
  align-items: center;
  justify-content: center;
  transform: rotate(-4deg);
  animation: stampIn 0.5s cubic-bezier(0.34, 1.56, 0.64, 1) 0.4s both;
  box-shadow: 0 0 0 3px rgba(166, 51, 43, 0.08);
}

/* Status / loading / error */
.status-line {
  font-size: 13px;
  color: var(--ink-soft);
  margin-top: 10px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.status-line.is-error {
  color: var(--maroon);
}

.spinner {
  width: 13px;
  height: 13px;
  border: 2px solid var(--paper-line);
  border-top-color: var(--green);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
}

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

.mock-banner {
  font-family: var(--font-mono);
  font-size: 11px;
  background: var(--gold);
  color: var(--green-deep);
  text-align: center;
  padding: 6px 10px;
  letter-spacing: 0.04em;
}

.hidden {
  display: none !important;
}