:root{--ink:#262823;--muted:#6c7067;--paper:#fbfaf6;--sand:#f1ede4;--line:#ded8ca;--accent:#735c35;--accent2:#335a54;--white:#fff;}
*{box-sizing:border-box} body{margin:0;background:var(--paper);color:var(--ink);font-family:"Microsoft YaHei","PingFang SC","Noto Sans SC",sans-serif;line-height:1.65}
a{color:inherit;text-decoration:none}.wrap{max-width:1180px;margin:auto;padding:0 28px}.topbar{height:68px;display:flex;align-items:center;justify-content:space-between;border-bottom:1px solid var(--line)}
.brand{font-weight:800;letter-spacing:.06em}.nav{display:flex;gap:24px;font-size:14px;color:var(--muted)}
.hero{padding:72px 0 52px;display:grid;grid-template-columns:1.1fr .9fr;gap:54px;align-items:center}.eyebrow{font-size:13px;letter-spacing:.18em;color:var(--accent2);font-weight:700}.hero h1{font-family:"Songti SC","SimSun",serif;font-size:52px;line-height:1.18;margin:14px 0 20px;letter-spacing:.035em}.lead{font-size:18px;color:#50544d;max-width:680px}.hero-actions{display:flex;gap:12px;margin-top:28px}.btn{display:inline-flex;align-items:center;padding:11px 18px;border:1px solid var(--ink);border-radius:999px;font-size:14px}.btn.primary{background:var(--ink);color:white}.author-card{background:#f4f1ea;border:1px solid var(--line);border-radius:22px;padding:14px;box-shadow:0 12px 36px rgba(50,45,35,.08)}.author-card img{width:100%;display:block;border-radius:14px;aspect-ratio:3/1;object-fit:cover}.author-note{font-size:12px;color:var(--muted);padding:10px 5px 0}
.section{padding:62px 0;border-top:1px solid var(--line)}.section-title{display:flex;justify-content:space-between;gap:30px;align-items:end;margin-bottom:26px}.section-title h2{font-size:28px;margin:0;font-family:"Songti SC","SimSun",serif}.section-title p{margin:0;color:var(--muted);font-size:14px}.grade-grid{display:grid;grid-template-columns:repeat(3,1fr);gap:16px}.grade-card{border:1px solid var(--line);border-radius:18px;padding:22px;background:#fff;transition:.18s}.grade-card:hover{transform:translateY(-2px);box-shadow:0 10px 26px rgba(40,35,28,.08)}.grade-num{font-size:12px;color:var(--accent2);font-weight:700;letter-spacing:.12em}.grade-card h3{font-size:24px;margin:8px 0 10px}.semester-links{display:flex;gap:8px}.semester-links a{font-size:13px;border:1px solid var(--line);border-radius:999px;padding:6px 12px;background:var(--paper)}
.principles{display:grid;grid-template-columns:repeat(4,1fr);gap:14px}.principle{padding:20px;border-top:3px solid var(--accent);background:white;border-radius:4px 4px 16px 16px}.principle h3{margin:0 0 8px;font-size:17px}.principle p{margin:0;color:var(--muted);font-size:14px}.resources{display:grid;grid-template-columns:repeat(3,1fr);gap:14px}.resource{border:1px solid var(--line);border-radius:14px;padding:18px;background:white}.footer{border-top:1px solid var(--line);padding:28px 0 46px;color:var(--muted);font-size:13px}
.volume-head{padding:52px 0 28px}.crumb{font-size:13px;color:var(--muted)}.volume-head h1{font-family:"Songti SC","SimSun",serif;font-size:38px;margin:10px 0}.status{font-size:14px;color:var(--muted)}.unit{margin:24px 0 32px}.unit h2{font-size:18px;margin:0 0 12px;padding-bottom:10px;border-bottom:1px solid var(--line)}.lesson-list{display:grid;grid-template-columns:1fr 1fr;gap:10px}.lesson{display:block;background:#fff;border:1px solid var(--line);border-radius:12px;padding:14px 16px}.lesson:hover{border-color:#ad9b79}.lesson .meta{font-size:11px;color:var(--accent2);margin-bottom:4px}.lesson .title{font-size:15px;font-weight:700}.empty{padding:42px;border:1px dashed #cfc7b8;border-radius:16px;color:var(--muted);text-align:center;background:#f8f6f0}.about-grid{display:grid;grid-template-columns:1fr .86fr;gap:40px;align-items:start}.about-grid h2{font-family:"Songti SC","SimSun",serif;font-size:30px}.small{font-size:13px;color:var(--muted)}
@media(max-width:850px){.hero,.about-grid{grid-template-columns:1fr}.hero{padding-top:44px}.hero h1{font-size:38px}.grade-grid{grid-template-columns:1fr 1fr}.principles{grid-template-columns:1fr 1fr}.lesson-list{grid-template-columns:1fr}.resources{grid-template-columns:1fr}.nav{display:none}}@media(max-width:520px){.wrap{padding:0 18px}.grade-grid,.principles{grid-template-columns:1fr}.hero h1{font-size:33px}}

/* Personal brand: 跨学科的陶老师 */
.brand-lockup{display:flex;align-items:center;gap:10px;min-width:0}
.brand-ip{font-size:13px;font-weight:800;letter-spacing:.08em;color:var(--accent2);white-space:nowrap}
.brand-divider{width:1px;height:18px;background:var(--line)}
.brand-project{font-size:13px;font-weight:700;letter-spacing:.035em;color:var(--ink);white-space:nowrap}
.ip-kicker{display:inline-flex;align-items:center;gap:8px;margin-bottom:12px;padding:7px 12px;border:1px solid #cfc6b4;border-radius:999px;background:#fff;color:var(--accent2);font-size:13px;font-weight:800;letter-spacing:.06em}
.ip-kicker:before{content:"";width:7px;height:7px;border-radius:50%;background:var(--accent)}
.ip-panel{display:grid;grid-template-columns:.75fr 1.25fr;gap:28px;align-items:center;background:#fff;border:1px solid var(--line);border-radius:18px;padding:24px 26px}
.ip-name{font-family:"Songti SC","SimSun",serif;font-size:30px;font-weight:800;margin:0 0 6px}.ip-role{font-size:15px;color:var(--accent2);font-weight:700;margin:0}.ip-desc{margin:0;color:var(--muted);font-size:14px}.footer-brand{font-weight:800;color:var(--accent2)}
@media(max-width:850px){.brand-project,.brand-divider{display:none}.ip-panel{grid-template-columns:1fr}}