/* 资料实战局 · 手绘练习本 */
:root {
  --bg: #fff9ec;
  --panel: #fffdf5;
  --panel2: #f2f6dd;
  --line: #d8dfbe;
  --text: #294637;
  --muted: #647365;
  --green: #6f963d;
  --yellow: #e5b34c;
  --red: #d97055;
  --blue: #6cb9d2;
  --radius: 20px;
  --shadow: 0 5px 0 rgba(78, 105, 55, .08);
  --studio-bg: #fff9ec;
  --studio-surface: #fffdf5;
  --studio-subtle: #f3f7e9;
  --studio-ink: #294637;
  --studio-ink-soft: #48664c;
  --studio-muted: #687563;
  --studio-accent: #6b933d;
  --studio-accent-wash: #edf5de;
  --studio-rule: #d6dfc1;
  --studio-display: "PingFang SC", "Noto Sans SC", "Microsoft YaHei", sans-serif;
}
html { background: var(--studio-bg); }
body {
  background: var(--studio-bg);
  color: var(--studio-ink);
  font-family: var(--studio-display);
  letter-spacing: -.015em;
}
.shell { grid-template-columns: 248px minmax(0,1fr); transition: grid-template-columns 240ms cubic-bezier(.22,1,.36,1); }
.side { background: #f7f2df; border-right: 1.5px solid #cfd9b3; }
.side-header { display: flex; align-items: center; justify-content: space-between; gap: 7px; margin: 0 2px 30px 5px; min-height: 44px; }
.side-header .brand { margin: 0; gap: 8px; font-size: 16px; line-height: 1.18; white-space: nowrap; }
.side-header .brand small { font-size: 9px; letter-spacing: .08em; }
.side-header .brand-mark { flex-basis: 40px; width: 40px; height: 40px; }
.sidebar-toggle { display: grid; place-items: center; flex: 0 0 31px; width: 31px; height: 31px; padding: 0; border: 1.5px solid #b7c99b; border-radius: 10px 9px 11px 8px; background: #fffdf5; color: #58794b; cursor: pointer; }
.sidebar-toggle svg { width: 19px; height: 19px; transition: transform 220ms ease; }
.sidebar-toggle:hover { background: #eaf3d8; border-color: #8fb15f; }
.sidebar-toggle:focus-visible { outline: 2px solid #658e3d; outline-offset: 3px; }
html.sidebar-collapsed .shell { grid-template-columns: 76px minmax(0,1fr); }
html.sidebar-collapsed .side { padding-right: 11px; padding-left: 11px; }
html.sidebar-collapsed .side-header { flex-direction: column; gap: 17px; margin: 0 0 24px; }
html.sidebar-collapsed .side-header .brand-name, html.sidebar-collapsed .nav button span, html.sidebar-collapsed .account-copy, html.sidebar-collapsed .account-indicator { display: none; }
html.sidebar-collapsed .side-header .brand-mark { flex-basis: 40px; }
html.sidebar-collapsed .sidebar-toggle svg { transform: rotate(180deg); }
html.sidebar-collapsed .nav button { position: relative; justify-content: center; width: 100%; min-height: 48px; padding: 10px; }
html.sidebar-collapsed .nav button.active::after { position: absolute; right: 3px; width: 5px; height: 5px; margin: 0; }
html.sidebar-collapsed .account-status { justify-content: center; min-height: 58px; padding: 8px 4px; }
html.sidebar-collapsed .account-avatar { flex-basis: 35px; width: 35px; height: 35px; }
.brand { font-family: var(--studio-display); font-weight: 850; letter-spacing: -.04em; }
.brand-mark { background: #83a64b; border-radius: 14px 12px 16px 11px; box-shadow: 3px 4px 0 #c8d9a7; transform: rotate(-4deg); }
.brand small { color: #758567; }
.nav button { color: #566d56; border-radius: 13px 11px 14px 10px; }
.nav button.active { background: #fffdf5; color: #355b3c; border: 1.5px solid #b9d097; box-shadow: 3px 4px 0 #e3eacb; transform: rotate(-.45deg); }
.nav button.active::after { background: #db7d5c; }
.side-foot { background: #fffdf5; border: 1.5px dashed #b5c991; border-radius: 15px; }
.account-status { display: flex; align-items: center; gap: 11px; min-height: 84px; padding: 13px 12px; }
.account-avatar { display: grid; place-items: center; flex: 0 0 37px; width: 37px; height: 37px; border: 1.5px solid #a8c989; border-radius: 12px 10px 13px 11px; background: #e7f2d4; color: #527d42; transform: rotate(-4deg); }
.account-avatar svg { width: 21px; height: 21px; transform: rotate(4deg); }
.account-copy { display: flex; flex: 1; min-width: 0; flex-direction: column; line-height: 1.25; }
.account-copy small { color: #74826e; font-size: 11px; font-weight: 650; }
.account-copy strong { margin: 4px 0 3px; color: #315b3b; font-size: 15px; font-weight: 800; }
.account-copy > span { color: #71816e; font-size: 11px; white-space: nowrap; }
.account-indicator { align-self: flex-start; flex: 0 0 8px; width: 8px; height: 8px; margin-top: 4px; border-radius: 50%; background: #7ca846; box-shadow: 0 0 0 3px #e8f3d7; }
.account-status.is-preview .account-indicator { background: #c6a666; box-shadow: 0 0 0 3px #f4e9cf; }
@media (max-width: 1000px) and (min-width: 681px) { .account-status { display: flex; } .account-copy > span { white-space: normal; } }
.bar { background: #e6ecd8; }
.bar i { background: #83aa4d; }
.shell > main { max-width: 1600px; padding: 32px clamp(21px,3vw,52px) 70px; }
.top h1 { color: #294637; font-family: var(--studio-display); font-weight: 880; letter-spacing: -.055em; }
.eyebrow { color: #719644; letter-spacing: .08em; }
.avatar { background: #78a348; border-radius: 50% 45% 48% 42%; box-shadow: 3px 3px 0 #d8e6b9; }
.streak::before { background: #db7956; }
.mission {
  min-height: 284px;
  isolation: isolate;
  overflow: hidden;
  border: 2px solid #b7ce94;
  border-radius: 22px 18px 24px 19px;
  background: #fffdf4;
  box-shadow: 5px 6px 0 #e1eaca;
}
.mission-art {
  position: absolute; z-index: -1; right: 0; top: 0;
  width: 57%; height: 100%; object-fit: cover; object-position: 72% 54%;
  -webkit-mask-image: linear-gradient(90deg, transparent, #000 18%);
  mask-image: linear-gradient(90deg, transparent, #000 18%);
}
.mission-row > div:first-child { max-width: 61%; }
.mission h2 { max-width: 440px; color: #2c523a; font-family: var(--studio-display); font-weight: 850; font-size: clamp(24px,2.1vw,32px); }
.mission p { color: #526b56; max-width: 440px; }
.mission-actions { max-width: 500px; }
.start-set { color: #fff; background: #719a42; border-radius: 12px 10px 13px 9px; box-shadow: 2px 3px 0 #ccdda9; }
.start-set.secondary { background: #fffefa; color: #496b3d; box-shadow: inset 0 0 0 1.5px #a6bf81; }
.goal-ring { background: #fffaf0; border: 1.5px dashed #c1d29f; color: #5f8840; transform: rotate(4deg); }
.steps { position: relative; z-index: 2; max-width: 64%; border-top: 1.5px dashed #c5d6a7; }
.step-dot { color: #68816a; }
.step-dot::before { background: #a8c97c; }
.step-dot.current::before { background: #e07d5b; }
@media (max-width: 1200px) {
  .mission-row > div:first-child { max-width: 68%; }
  .mission-art { width: 50%; opacity: .85; }
}
@media (max-width: 720px) {
  .side { background: rgba(255,249,236,.97); border-bottom-color: #d5dfbd; }
  .mission { min-height: 0; padding-bottom: 20px; }
  .mission-row > div:first-child { max-width: none; }
  .mission-art { position: relative; z-index: 0; display: block; width: calc(100% + 40px); height: 168px; margin: -20px -20px 17px; object-position: 66% 60%; -webkit-mask-image: none; mask-image: none; opacity: 1; }
  .mission-row { position: relative; }
  .steps { max-width: 100%; }
}

/* A soft picture-book palette, with functional surfaces still easy to scan. */
.quick {
  color: #2d5d50;
  border: 2px solid #a6d4d0;
  border-radius: 20px 24px 18px 21px;
  background: #dff2ee;
  box-shadow: 5px 6px 0 #c8e6df;
}
.quick h3, .quick .metric, .quick .metric b { color: #2b5b50; }
.quick .delta { color: #527b49; }
.quick .metric { background: #fffef4; border: 1.5px solid #b4d8ca; border-radius: 13px 11px 15px 10px; }
.quick .metric span, .quick .weak { color: #547268; }
.quick .weak { border-color: #aed6cc; }
.quick .weak strong { color: #3e764a; }
.card, .basic-module, .stem-card, .lesson-unit, .module-book-question, .course-homework-question, .course-homework-side {
  border: 1.5px solid #c8d7ae;
  border-radius: 19px 17px 21px 18px;
  background: #fffdf5;
  box-shadow: 4px 5px 0 rgba(139, 169, 91, .12);
}
.card-title h3, .task h2 { color: #2e5238; }
.tag { color: #527640; background: #edf4db; border: 1px dashed #adc688; border-radius: 30px; }
.question { border-left: 0; border: 1.5px solid #e5cf8e; border-radius: 15px 12px 17px 13px; background: #fff4c8; color: #3d593d; }
.source { color: #385444; }
.source button { color: #407f72; text-decoration-color: #7bb8aa; }
.source button.selected { color: #2f6441; background: #e9f5cc; box-shadow: inset 0 0 0 1.5px #8ab45c; }
.source button.wrong { color: #a85040; background: #fbe6d9; box-shadow: inset 0 0 0 1.5px #dd9b7e; }
.hint { border-top: 1px dashed #cbdab3; color: #6b7a64; }
.task { background: #fffdf5; }
.counter { color: #6f963d; }
.timer { color: #507444; border: 1.5px dashed #bbcf9e; background: #f5f9eb; border-radius: 10px; }
.pick, .exam-option, .choice-chip, .course-answer, .course-answers button, .module-book-options button, .course-homework-option {
  border: 1.5px solid #cbd9b8;
  border-radius: 12px 10px 13px 10px;
  background: #fffef8;
  color: #355544;
}
.pick.selected, .exam-option.selected, .choice-chip.selected, .formula-choice.selected, .eliminate-option.selected, .speed-strategy.selected,
.course-answer.selected, .course-answers button.selected, .module-book-options button.selected, .course-homework-option.selected {
  border-color: #7ea84d; background: #edf5d8; color: #315d3d; box-shadow: inset 4px 0 #82a94f;
}
.primary, .start-set, .basic-enter, .stem-submit, .exam-next, .submit-set, .module-book-submit, .course-homework-primary {
  background: #709940;
  color: #fff;
  border-radius: 11px 9px 12px 9px;
  box-shadow: 2px 3px 0 #cee0aa;
}
.ghost, .exam-prev, .stem-nav button, .module-book-nav button, .course-homework-secondary { background: #eaf2d7; color: #3b6140; border-radius: 10px; }
.feedback.ok, .stem-result, .exam-result { color: #3c6e44; background: #edf7df; border-color: #b4d090; }
.feedback.bad { color: #a24d3e; background: #ffebe4; border-color: #ebbaa7; }
.diagnostic { border-top: 3px solid #91b659; }
.diagnosis { background: #f7f9eb; border-color: #d4e0b6; }
.pulse { background: #83a94f; }

/* Training, lesson and homework pages are chapters of the same notebook. */
.exam-overlay, .stem-overlay, .basic-overlay, .course-overlay, .module-book-overlay, .course-homework, .basic-page, .course-content, .module-book-layout, .stem-body { background: #fff9ec; }
.exam-head, .module-book-head, .course-homework-head {
  background: #fffdf3;
  border-bottom: 1.5px solid #c8d7ac;
  box-shadow: 0 3px 0 rgba(125, 157, 89, .07);
}
.exam-head h2, .module-book-head h2 { color: #2b563b; font-weight: 820; }
.close-exam, .course-homework-back { background: #fffefa; color: #497246; border: 1.5px solid #adc88d; border-radius: 12px 10px 13px 9px; }
.course-menu, .module-book-menu { background: #f5f2df; border-color: #d0dab3; }
.course-progress { background: #fffdf5; border: 1.5px solid #cad8ad; border-radius: 16px; }
.course-progress .bar { background: #e5edcf; }
.course-progress .bar i { background: #84aa50; }
.course-list button, .module-book-list button { color: #536d4d; border-radius: 12px 10px 14px 10px; }
.course-list button.active, .module-book-list button.active {
  color: #3f6c40; background: #fffdf5; border: 1.5px solid #b7cc92; box-shadow: inset 4px 0 #83a94f, 3px 3px 0 #e1e8cf;
}
.course-lesson h1, .basic-intro h2, .module-book-top h2, .course-homework-intro h1 { color: #2b563b; font-weight: 860; letter-spacing: -.055em; }
.course-kicker, .lesson-unit-index, .question-kicker, .stem-number { color: #709640; }
.lesson-unit-index { background: #e9f2d1; border: 1.5px solid #b6cd8a; color: #466d39; transform: rotate(-5deg); }
.course-lead, .basic-intro p, .module-book-top p, .course-homework-intro p { color: #667661; }
.lesson-outline-item { background: #fffdf5; border: 1.5px solid #cad8ad; border-radius: 15px 11px 17px 12px; box-shadow: 3px 4px 0 #e4ebd1; }
.lesson-outline-item.active { border-color: #8daf5e; background: #edf5d8; box-shadow: inset 0 0 0 1px #8daf5e; }
.lesson-outline-item b, .lesson-unit h3, .lesson-unit-head h3 { color: #31583c; }
.lesson-unit { background: #fffdf6; }
.lesson-unit:nth-of-type(3n+2) { border-color: #afd4d1; box-shadow: 4px 5px 0 #d8eeeb; }
.lesson-unit:nth-of-type(3n+3) { border-color: #ead9aa; box-shadow: 4px 5px 0 #f3ebd2; }
.course-concept, .lesson-scenario, .lesson-story, .lesson-bridge, .module-example, .quantity-card { background: #f4f8e8; }
.course-formula, .formula-row, .module-purpose, .correction-formula, .error-budget { background: #eaf3d7; color: #355e40; }
.course-tip, .method-limit { background: #fff3d5; }
.course-quiz { background: #edf5e6; }
.lesson-concept-visual { border: 1.5px solid #cad8ad; background: #fff9ed; border-radius: 15px; }
.lesson-concept-visual img { background: #fff9ed; }
.lesson-concept-visual figcaption { border-color: #d9e2c2; color: #617358; }
.basic-inner { max-width: 1350px; }
.basic-intro { min-height: 235px; align-items: center; gap: 25px; }
.basic-intro > div:first-child { max-width: 650px; }
.basic-art-wrap { position: relative; flex: 0 1 430px; align-self: stretch; min-width: 270px; }
.basic-art { width: 100%; height: 205px; object-fit: cover; object-position: 45% 60%; border: 1.5px solid #b9cf92; border-radius: 18px 14px 21px 15px; box-shadow: 4px 5px 0 #e2eacb; }
.basic-count { position: absolute; right: 12px; bottom: 0; background: #fffdf3; color: #4f743d; border: 1.5px solid #afca8e; border-radius: 30px; box-shadow: 2px 2px 0 #d6e4b8; }
.basic-index { background: #7ea44a; color: #fff; border-radius: 11px 9px 12px 8px; transform: rotate(-4deg); }
.basic-module h3 { color: #315a3c; }
.basic-module footer { border-color: #d5e0c0; }
.basic-enter { font-weight: 750; }
.course-homework-shell { background: #fff9ec; }
.course-homework-side { background: #f6f8e9; }
.course-homework-grid button { background: #fffdf5; border: 1px solid #cbd9b4; border-radius: 8px 7px 10px 7px; }
.course-homework-grid button.answered, .module-book-sheet button.answered { background: #e5f0cc; color: #466e3f; border-color: #a9c985; }
.course-homework-progress { background: #e6eccf; }
.course-homework-progress i { background: #83a94f; }
.course-homework-material, .course-homework-explanation { background: #f5f8e9; border-color: #cbdab3; }

/* Test-taking surfaces preserve contrast and chart legibility. */
.paper-pane { background: #f0f4df; border-right-color: #d3dfb6; }
.paper-frame, .answer-pane { background: #fffdf5; border-color: #cbdab3; }
.material-copy { color: #355140; }
.material-copy th, .stem-material th, .module-book-native-table tr:first-child td, .module-book-native-table th { background: #e7f2d4; }
.material-copy th, .material-copy td, .stem-material th, .stem-material td,
.module-book-native-table td, .module-book-native-table th { border-color: #c5d4a9; }
.answer-sheet, .stem-sheet { border-color: #d5e0bf; }
.answer-dot, .stem-dot, .module-book-sheet button { background: #fffdf5; border-color: #cbd8b3; color: #55714f; border-radius: 8px; }
.answer-dot.current, .stem-dot.current, .module-book-sheet button.current { outline-color: #6c993e; color: #47703e; }
.time-box, .time-box.total { background: #f2f8e5; border-color: #c6d9ab; }
.time-box strong, .time-box.total strong { color: #57823f; }
.timer-toggle { background: #7da34c; }
.stem-original-options li, .identify-row { background: #fffdf5; border: 1.5px solid #cbd9b4; }
.capture-num { background: #e3f1df; color: #3d7145; }
.capture-num.selected { background: #7fa34b; color: #fff; }
.module-book-main { background: #fff9ec; }
.module-book-panel-head { border-color: #d4dfbb; }
.module-book-native-content { color: #34503e; }
.module-book-native-chart, .module-book-native-table-wrap, .module-book-svg-chart { background: #fffef7; border-color: #cbd8b4; }
.module-book-native-table tr:nth-child(even) { background: #fbfcf2; }
.module-book-chart-legend { color: #607359; }
.module-book-score { color: #5b823c; }

@media (hover: hover) and (pointer: fine) {
  .nav button:hover, .course-list button:hover, .module-book-list button:hover { background: #fffdf5; color: #3f6a3e; }
  .start-set:hover, .primary:hover, .basic-enter:hover, .stem-submit:hover, .module-book-submit:hover { background: #5e8739; }
  .pick:hover, .exam-option:hover, .module-book-options button:hover { background: #f5f9e9; border-color: #96b76b; }
  .lesson-outline-item:hover { background: #f5f9e9; border-color: #a8c783; }
}
@media (max-width: 1150px) {
  .basic-intro { align-items: flex-start; }
  .basic-art-wrap { flex-basis: 360px; }
}
@media (max-width: 1000px) and (min-width: 681px) {
  .shell { grid-template-columns: 176px minmax(0,1fr); }
  html.sidebar-collapsed .shell { grid-template-columns: 76px minmax(0,1fr); }
  .side-header .brand-name { display: none; }
  .side-header { margin-right: 0; }
}
@media (max-width: 800px) {
  .basic-intro { display: block; }
  .basic-art-wrap { width: min(100%, 520px); margin-top: 20px; min-width: 0; }
  .basic-art { height: 175px; }
  .basic-count { bottom: -10px; }
}
@media (max-width: 680px) { .shell, html.sidebar-collapsed .shell { display: block; } }
@media (prefers-reduced-motion: reduce) { .shell, .sidebar-toggle svg { transition: none; } }
@media (max-width: 720px) {
  .quick, .card { box-shadow: 3px 4px 0 rgba(139,169,91,.12); }
  .mission h2 { font-size: 23px; }
  .mission-art { z-index: 0; }
  .steps { margin-top: 23px; }
  .basic-intro { min-height: 0; }
}
@media (prefers-reduced-motion: reduce) {
  .nav button.active, .basic-index, .goal-ring { transform: none; }
}

/* 第一课：从真实例题进入概念，图像与提问一起构成完整的导入。 */
.lesson-story-intro{display:grid;grid-template-columns:minmax(0,1fr) 220px;overflow:hidden;margin:3px 0 23px;border:1.5px solid #a9c796;border-radius:18px 16px 20px 16px;background:#f8f7e9;box-shadow:3px 4px 0 #e4ecd6}
.lesson-story-copy{min-width:0;padding:22px 24px 20px}
.lesson-story-kicker{display:inline-flex;align-items:center;gap:7px;color:#588356;font-size:12px;font-weight:850;letter-spacing:.11em}
.lesson-story-kicker::before{content:"";width:19px;height:2px;border-radius:4px;background:#d98f71;transform:rotate(-5deg)}
.lesson-story-copy h4{margin:8px 0 10px;color:#315e43;font-size:21px;line-height:1.4;letter-spacing:-.02em}
.lesson-story-copy>p{margin:0;color:#49634b;font-size:15px;line-height:1.8}
.lesson-story-question{display:grid;gap:4px;margin-top:16px;padding:11px 13px;border-left:3px solid #e7ad69;border-radius:3px 10px 10px 3px;background:#fff6de;color:#513e2e;line-height:1.65}
.lesson-story-question b{color:#a5623a;font-size:12px;letter-spacing:.08em}
.lesson-story-question span{font-size:14px;font-weight:650}
.lesson-story-clue{margin-top:12px;border-top:1px dashed #b6c6a8;padding-top:9px;color:#426347;font-size:13px;line-height:1.7}
.lesson-story-clue summary{width:max-content;max-width:100%;cursor:pointer;font-weight:800;list-style:none;transition:color .18s ease}
.lesson-story-clue summary::-webkit-details-marker{display:none}
.lesson-story-clue summary::after{content:" ＋";font-size:16px;vertical-align:-1px}
.lesson-story-clue[open] summary::after{content:" −"}
.lesson-story-clue summary:hover{color:#a5623a}
.lesson-story-clue summary:focus-visible{outline:2px solid #618c60;outline-offset:3px;border-radius:3px}
.lesson-story-clue p{margin:8px 0 0;color:#49634b}
.lesson-story-visual{position:relative;min-height:270px;margin:0;background:#dceccf}
.lesson-story-visual img{display:block;width:100%;height:100%;position:absolute;inset:0;object-fit:cover}
.lesson-story-visual figcaption{position:absolute;right:9px;bottom:9px;left:9px;padding:6px 9px;border-radius:8px;background:rgba(255,252,236,.91);color:#315e43;font-size:11px;line-height:1.4;text-align:center;box-shadow:0 1px 4px rgba(30,65,42,.09)}
@media(max-width:700px){.lesson-story-intro{grid-template-columns:1fr}.lesson-story-copy{padding:18px 18px 17px}.lesson-story-copy h4{font-size:19px}.lesson-story-visual{height:215px;min-height:0}.lesson-story-visual img{object-position:center 47%}}