*,*::before,*::after{margin:0;padding:0;box-sizing:border-box}
:root{
  --bg:#f8fafc;--surface:#ffffff;--surface2:#f1f5f9;--surface3:#e2e8f0;
  --border:#e2e8f0;--text:#1e293b;--text2:#475569;--text3:#94a3b8;
  --accent:#6366f1;--accent2:#4f46e5;--accent-glow:rgba(99,102,241,.12);
  --math:#d97706;--physics:#0891b2;--chemistry:#16a34a;
  --radius:12px;--radius-lg:20px;
}
html.dark{
  --bg:#0a0e17;--surface:#111827;--surface2:#1e293b;--surface3:#293548;
  --border:#334155;--text:#e2e8f0;--text2:#94a3b8;--text3:#64748b;
  --accent:#818cf8;--accent2:#a5b4fc;--accent-glow:rgba(99,102,241,.25);
  --math:#f59e0b;--physics:#06b6d4;--chemistry:#22c55e;
}
html{font-size:16px;scroll-behavior:smooth}
body{font-family:'Noto Sans SC',system-ui,sans-serif;background:var(--bg);color:var(--text);min-height:100vh;overflow-x:hidden}

/* Top Navigation Bar */
.top-nav{position:fixed;top:0;left:0;right:0;height:52px;background:var(--surface);border-bottom:1px solid var(--border);display:flex;align-items:center;justify-content:space-between;padding:0 16px;z-index:1000}
.top-nav-left{display:flex;align-items:center;gap:12px}
.nav-menu-btn{width:36px;height:36px;border:none;border-radius:8px;background:transparent;font-size:1.2rem;cursor:pointer;color:var(--text);display:flex;align-items:center;justify-content:center}
.nav-menu-btn:hover{background:var(--surface2)}
.top-nav-logo{font-size:1rem;font-weight:700;color:var(--accent)}
.top-nav-right{display:flex;align-items:center;gap:10px}
.login-btn{padding:7px 16px;border:1px solid var(--accent);border-radius:8px;background:transparent;color:var(--accent);font-size:.8rem;font-weight:500;cursor:pointer;font-family:inherit;transition:all .2s}
.login-btn:hover{background:var(--accent);color:#fff}
.user-phone{font-size:.8rem;color:var(--text2)}
.logout-btn{padding:5px 12px;border:1px solid var(--border);border-radius:6px;background:transparent;color:var(--text3);font-size:.75rem;cursor:pointer;font-family:inherit}
.logout-btn:hover{border-color:var(--accent);color:var(--accent)}

/* Left Sidebar */
.app-sidebar{position:fixed;top:52px;left:0;bottom:0;width:260px;background:var(--surface);border-right:1px solid var(--border);padding:16px;overflow-y:auto;z-index:900;transition:transform .3s}
.new-task-btn{width:100%;padding:12px;border:2px dashed var(--border);border-radius:10px;background:transparent;color:var(--accent);font-size:.9rem;font-weight:600;cursor:pointer;font-family:inherit;transition:all .2s;margin-bottom:16px}
.new-task-btn:hover{border-color:var(--accent);background:rgba(99,102,241,.05)}
.history-title{font-size:.75rem;font-weight:600;color:var(--text3);text-transform:uppercase;letter-spacing:.05em;margin-bottom:10px}
.history-list{display:flex;flex-direction:column;gap:4px}
.history-item{padding:10px 12px;border-radius:8px;cursor:pointer;transition:all .2s}
.history-item:hover{background:var(--surface2)}
.history-item-title{font-size:.85rem;color:var(--text);white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.history-item-header{display:flex;align-items:center;gap:6px}
.history-item-header .history-item-title{flex:1;min-width:0}
.history-status{font-size:.65rem;padding:2px 7px;border-radius:4px;white-space:nowrap;font-weight:500}
.history-status.generating{background:rgba(99,102,241,.12);color:var(--accent);animation:pulse 1.5s infinite}
.history-status.done{background:rgba(34,197,94,.1);color:#16a34a}
.history-status.failed{background:rgba(239,68,68,.1);color:#dc2626}
@keyframes pulse{0%,100%{opacity:1}50%{opacity:.5}}
.history-item-time{font-size:.7rem;color:var(--text3);margin-top:3px}
.history-empty{font-size:.8rem;color:var(--text3);text-align:center;padding:30px 0}

/* App Main */
.app-main{margin-left:260px;margin-top:52px;min-height:calc(100vh - 52px)}

/* Auth Modal */
.auth-overlay{position:fixed;inset:0;z-index:2000;background:rgba(0,0,0,.5);backdrop-filter:blur(4px);display:none;align-items:center;justify-content:center}
.auth-overlay.show{display:flex}
.auth-modal{background:var(--surface);border:1px solid var(--border);border-radius:16px;padding:32px;width:360px;position:relative}
.auth-tabs{display:flex;gap:0;margin-bottom:24px;border-bottom:1px solid var(--border)}
.auth-tab{flex:1;padding:10px;border:none;background:transparent;color:var(--text3);font-size:.9rem;font-weight:500;cursor:pointer;font-family:inherit;border-bottom:2px solid transparent;transition:all .2s}
.auth-tab.active{color:var(--accent);border-bottom-color:var(--accent)}
.auth-form{display:flex;flex-direction:column;gap:14px}
.auth-form input{padding:12px 14px;border:1px solid var(--border);border-radius:10px;font-size:.9rem;font-family:inherit;background:var(--bg);color:var(--text);outline:none}
.auth-form input:focus{border-color:var(--accent)}
.sms-row{display:flex;gap:10px}
.sms-row input{flex:1}
.sms-btn{padding:12px 14px;border:none;border-radius:10px;background:var(--surface2);color:var(--accent);font-size:.8rem;font-weight:500;cursor:pointer;font-family:inherit;white-space:nowrap}
.sms-btn:disabled{opacity:.5;cursor:not-allowed}
.auth-submit{padding:14px;border:none;border-radius:10px;background:linear-gradient(135deg,#6366f1,#4f46e5);color:#fff;font-size:.95rem;font-weight:600;cursor:pointer;font-family:inherit}
.auth-close{position:absolute;top:12px;right:12px;width:28px;height:28px;border:none;border-radius:50%;background:var(--surface2);color:var(--text3);font-size:16px;cursor:pointer;display:flex;align-items:center;justify-content:center}

/* Responsive */
@media(max-width:900px){
  .app-sidebar{transform:translateX(-100%)}
  .app-sidebar.open{transform:translateX(0);box-shadow:4px 0 20px rgba(0,0,0,.1)}
  .app-main{margin-left:0}
}

/* Hero */
.hero{position:relative;padding:60px 40px 40px;text-align:center;overflow:hidden}
.hero-bg{position:absolute;inset:0;background:
  radial-gradient(ellipse 60% 50% at 50% 0%,rgba(99,102,241,.08),transparent),
  radial-gradient(ellipse 40% 60% at 80% 20%,rgba(8,145,178,.06),transparent),
  radial-gradient(ellipse 40% 60% at 20% 30%,rgba(217,119,6,.05),transparent);
  z-index:0}
.hero-content{position:relative;z-index:1;max-width:800px;margin:0 auto}
.hero-badge{display:inline-block;padding:6px 18px;border-radius:20px;font-size:.8rem;color:var(--accent2);border:1px solid rgba(99,102,241,.3);background:rgba(99,102,241,.08);margin-bottom:20px}
.hero h1{font-size:2.2rem;font-weight:900;background:linear-gradient(135deg,var(--text) 0%,var(--accent) 50%,var(--accent2) 100%);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text;margin-bottom:8px;letter-spacing:-.02em}
.hero-sub{font-size:1rem;color:var(--text2);margin-bottom:24px}

/* Hero生成框 */
.hero-gen-box{display:flex;gap:10px;max-width:700px;margin:0 auto 20px;position:relative}
.hero-gen-box input{flex:1;padding:36px 24px;border:2px solid var(--border);border-radius:16px;font-size:1.1rem;font-family:inherit;background:var(--surface);color:var(--text);outline:none;transition:border-color .2s;box-shadow:0 4px 20px rgba(0,0,0,.04)}
.hero-gen-box input:focus{border-color:var(--accent);box-shadow:0 4px 24px var(--accent-glow)}
.hero-gen-box input::placeholder{color:var(--text3)}
.hero-gen-box button{padding:36px 32px;border:none;border-radius:16px;background:linear-gradient(135deg,#6366f1,#4f46e5);color:#fff;font-size:1.05rem;font-weight:700;cursor:pointer;font-family:inherit;white-space:nowrap;transition:all .2s;box-shadow:0 4px 16px rgba(99,102,241,.3)}
.hero-gen-box button:hover{transform:translateY(-2px);box-shadow:0 6px 24px rgba(99,102,241,.4)}
.hero-gen-box button:disabled{opacity:.6;cursor:not-allowed;transform:none}
.hero-examples{display:flex;gap:8px;justify-content:center;flex-wrap:wrap;margin-bottom:16px}
.hero-examples span{padding:6px 14px;border-radius:20px;font-size:.8rem;background:var(--surface2);color:var(--accent);cursor:pointer;transition:all .2s;border:1px solid transparent}
.hero-examples span:hover{background:rgba(99,102,241,.1);border-color:var(--accent)}
.hero-progress{display:none;max-width:500px;margin:0 auto;align-items:center;gap:12px}
.hero-progress.show{display:flex}
.hero-progress-bar{flex:1;height:6px;background:var(--surface2);border-radius:3px;overflow:hidden}
.hero-progress-fill{height:100%;width:0;background:linear-gradient(90deg,#6366f1,#a855f7);border-radius:3px;transition:width .5s}
.hero-progress-text{font-size:.8rem;color:var(--text2);white-space:nowrap}
.stats{display:flex;gap:30px;justify-content:center;flex-wrap:wrap}
.stat{text-align:center}
.stat-num{font-size:2rem;font-weight:700;color:var(--text)}
.stat-label{font-size:.8rem;color:var(--text3);margin-top:2px}

/* Section Header */
.section-header{text-align:center;padding:40px 20px 20px;border-top:1px solid var(--border)}
.section-header h2{font-size:1.5rem;font-weight:800;color:var(--text);margin-bottom:6px}
.section-header p{font-size:.9rem;color:var(--text3)}

/* Level Tabs */
.level-tabs{display:flex;justify-content:center;gap:8px;padding:20px;position:sticky;top:0;z-index:100;background:rgba(248,250,252,.85);backdrop-filter:blur(20px);border-bottom:1px solid var(--border)}
html.dark .level-tabs{background:rgba(10,14,23,.85)}
.theme-toggle{width:40px;height:40px;border-radius:50%;border:1px solid var(--border);background:var(--surface);font-size:1.1rem;cursor:pointer;display:flex;align-items:center;justify-content:center;margin-left:12px;transition:all .2s}
.theme-toggle:hover{border-color:var(--accent);transform:scale(1.1)}

/* AI生成输入框 */
.ai-gen-inline{display:flex;gap:6px;margin-left:auto;margin-right:8px}
.ai-gen-inline input{width:280px;padding:9px 14px;border:2px solid var(--border);border-radius:10px;background:var(--surface);color:var(--text);font-size:.85rem;font-family:inherit;outline:none;transition:border-color .2s}
.ai-gen-inline input:focus{border-color:var(--accent)}
.ai-gen-inline input::placeholder{color:var(--text3)}
.ai-gen-inline button{padding:9px 18px;border:none;border-radius:10px;background:linear-gradient(135deg,#6366f1,#4f46e5);color:#fff;font-size:.85rem;font-weight:600;cursor:pointer;font-family:inherit;white-space:nowrap;transition:all .2s}
.ai-gen-inline button:hover{transform:translateY(-1px);box-shadow:0 4px 12px rgba(99,102,241,.3)}
.ai-gen-inline button:disabled{opacity:.6;cursor:not-allowed;transform:none}

/* AI进度条 */
.ai-progress-bar{display:none;align-items:center;gap:12px;padding:10px 20px;background:var(--surface);border-bottom:1px solid var(--border);animation:slideDown .3s ease}
.ai-progress-bar.show{display:flex}
@keyframes slideDown{from{opacity:0;transform:translateY(-10px)}to{opacity:1;transform:translateY(0)}}
.ai-progress-inner{flex:1;height:6px;background:var(--surface2);border-radius:3px;overflow:hidden}
.ai-progress-fill{height:100%;width:0;background:linear-gradient(90deg,#6366f1,#a855f7);border-radius:3px;transition:width .5s ease}
.ai-progress-text{font-size:.8rem;color:var(--text2);white-space:nowrap;min-width:120px}
.ai-progress-close{width:24px;height:24px;border-radius:50%;border:1px solid var(--border);background:transparent;color:var(--text3);font-size:14px;cursor:pointer;display:flex;align-items:center;justify-content:center}
.ai-progress-close:hover{background:var(--surface2);color:var(--text)}

@media(max-width:900px){.ai-gen-inline{display:none}}
.tab{padding:10px 32px;border:1px solid var(--border);border-radius:30px;background:transparent;color:var(--text2);font-size:.95rem;cursor:pointer;transition:all .25s;font-family:inherit}
.tab:hover{border-color:var(--accent);color:var(--text)}
.tab.active{background:var(--accent);border-color:var(--accent);color:#fff;box-shadow:0 4px 20px var(--accent-glow)}

/* Content Layout */
.content{display:flex;max-width:1400px;margin:0 auto;padding:30px 20px;gap:24px;min-height:70vh}
.sidebar{width:280px;flex-shrink:0;position:sticky;top:90px;height:fit-content;max-height:calc(100vh - 120px);overflow-y:auto}
.sidebar::-webkit-scrollbar{width:4px}
.sidebar::-webkit-scrollbar-thumb{background:var(--surface3);border-radius:4px}
.main-area{flex:1;min-width:0}

/* Sidebar Styles */
.subject-group{margin-bottom:16px}
.subject-title{padding:10px 16px;font-size:.85rem;font-weight:700;color:var(--text3);text-transform:uppercase;letter-spacing:.05em;display:flex;align-items:center;gap:8px}
.subject-dot{width:8px;height:8px;border-radius:50%}
.subject-dot.math{background:var(--math)}
.subject-dot.physics{background:var(--physics)}
.subject-dot.chemistry{background:var(--chemistry)}
.subject-dot.biology{background:#22c55e}
.subject-dot.geography{background:#14b8a6}
.subject-dot.history{background:#d97706}
.subject-dot.chinese{background:#ef4444}
.subject-dot.english{background:#3b82f6}
.subject-dot.science{background:#22c55e}
.subject-dot.politics{background:#8b5cf6}
.subject-dot.chinese{background:var(--chinese)}
.subject-dot.english{background:var(--english)}
.subject-dot.science{background:var(--science)}
.subject-dot.biology{background:var(--biology)}
.subject-dot.history{background:var(--history)}
.subject-dot.geography{background:var(--geography)}
.subject-dot.politics{background:var(--politics)}

.grade-btn{display:block;width:100%;padding:10px 16px 10px 34px;border:none;background:transparent;color:var(--text2);font-size:.9rem;text-align:left;cursor:pointer;transition:all .2s;border-radius:8px;font-family:inherit}
.grade-btn:hover{background:var(--surface2);color:var(--text)}
.grade-btn.active{background:var(--surface2);color:var(--accent2);font-weight:500}
/* Main Content Cards */
.volume-section{margin-bottom:40px}
.volume-title{font-size:1.3rem;font-weight:700;color:var(--text);margin-bottom:20px;padding-bottom:10px;border-bottom:1px solid var(--border);display:flex;align-items:center;gap:10px}
.volume-badge{padding:4px 12px;border-radius:6px;font-size:.75rem;font-weight:500}
.volume-badge.math{background:rgba(245,158,11,.15);color:var(--math)}
.volume-badge.physics{background:rgba(6,182,212,.15);color:var(--physics)}
.volume-badge.chemistry{background:rgba(34,197,94,.15);color:var(--chemistry)}
.volume-badge.chinese{background:rgba(239,68,68,.15);color:var(--chinese)}
.volume-badge.english{background:rgba(59,130,246,.15);color:var(--english)}
.volume-badge.science{background:rgba(34,197,94,.15);color:var(--science)}
.volume-badge.biology{background:rgba(34,197,94,.15);color:var(--biology)}
.volume-badge.history{background:rgba(217,119,6,.15);color:var(--history)}
.volume-badge.geography{background:rgba(20,184,166,.15);color:var(--geography)}
.volume-badge.politics{background:rgba(139,92,246,.15);color:var(--politics)}

.chapter-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;margin-bottom:14px;transition:all .25s;cursor:default}
.chapter-card:hover{border-color:var(--accent);transform:translateY(-1px);box-shadow:0 8px 30px rgba(0,0,0,.08)}
.chapter-card.has-courseware{cursor:pointer;border-left:3px solid var(--accent)}
.chapter-card.has-courseware:hover{border-color:var(--accent);background:rgba(99,102,241,.03);box-shadow:0 8px 30px var(--accent-glow)}
.chapter-header{display:flex;justify-content:space-between;align-items:flex-start;margin-bottom:12px}
.chapter-name{font-size:1.05rem;font-weight:600;color:var(--text)}
.chapter-topic{font-size:.85rem;color:var(--text3);margin-top:4px}
.has3d-badge{padding:3px 10px;border-radius:6px;font-size:.7rem;font-weight:600;background:linear-gradient(135deg,var(--accent),#a855f7);color:#fff;white-space:nowrap;cursor:pointer}
.has3d-badge.soon{background:var(--surface3);color:var(--text3);cursor:default}
.has2d-badge{padding:3px 10px;border-radius:6px;font-size:.7rem;font-weight:600;background:linear-gradient(135deg,#06b6d4,#0891b2);color:#fff;white-space:nowrap;cursor:pointer}
.points-list{display:flex;flex-wrap:wrap;gap:8px}
.point-tag{padding:5px 12px;border-radius:6px;font-size:.8rem;background:var(--surface2);color:var(--text2);border:1px solid transparent;transition:all .2s}
.point-tag:hover{border-color:var(--accent);color:var(--text)}
.point-tag.clickable{cursor:pointer;border-color:rgba(99,102,241,.3);background:rgba(99,102,241,.08);color:var(--accent2);transition:all .2s}
.point-tag.clickable:hover{background:var(--accent);border-color:var(--accent);color:#fff;transform:translateY(-2px);box-shadow:0 4px 12px var(--accent-glow)}
/* 3D Courseware Link */
.courseware-link{display:inline-flex;align-items:center;gap:6px;margin-top:14px;padding:8px 18px;border-radius:8px;background:linear-gradient(135deg,rgba(99,102,241,.15),rgba(168,85,247,.15));border:1px solid rgba(99,102,241,.3);color:var(--accent2);font-size:.85rem;text-decoration:none;transition:all .25s}
.courseware-link:hover{background:linear-gradient(135deg,rgba(99,102,241,.25),rgba(168,85,247,.25));transform:translateY(-1px)}
.courseware-link svg{width:16px;height:16px}

/* Empty State */
.empty-state{text-align:center;padding:60px 20px;color:var(--text3)}
.empty-state h3{font-size:1.2rem;color:var(--text2);margin-bottom:8px}

/* Footer */
.footer{text-align:center;padding:40px 20px;border-top:1px solid var(--border);margin-top:40px}
.footer p{font-size:.85rem;color:var(--text3);margin-bottom:6px}
.footer a{color:var(--accent2);text-decoration:none}

/* User Area Badges */
.user-badge{padding:3px 10px;border-radius:12px;font-size:.72rem;font-weight:600;background:linear-gradient(135deg,rgba(99,102,241,.15),rgba(168,85,247,.15));color:var(--accent);border:1px solid rgba(99,102,241,.3)}
.plan-btn{padding:5px 12px;border:1px solid var(--accent);border-radius:6px;background:transparent;color:var(--accent);font-size:.75rem;cursor:pointer;font-family:inherit;font-weight:500;transition:all .2s}
.plan-btn:hover{background:var(--accent);color:#fff}

/* Auth Form Additions */
.auth-switch{text-align:center;margin-top:14px}
.auth-link{font-size:.82rem;color:var(--accent);cursor:pointer}
.auth-link:hover{text-decoration:underline}

/* Plan Modal */
.plan-overlay{position:fixed;inset:0;z-index:2000;background:rgba(0,0,0,.5);backdrop-filter:blur(4px);display:none;align-items:center;justify-content:center}
.plan-overlay.show{display:flex}
.plan-modal{background:var(--surface);border:1px solid var(--border);border-radius:20px;padding:36px;width:680px;max-width:95vw;position:relative;max-height:90vh;overflow-y:auto}
.plan-title{font-size:1.3rem;font-weight:700;color:var(--text);text-align:center;margin-bottom:24px}
.plan-grid{display:grid;grid-template-columns:repeat(2,1fr);gap:16px}
@media(max-width:600px){.plan-grid{grid-template-columns:1fr}}
.plan-card{position:relative;border:2px solid var(--border);border-radius:14px;padding:24px 20px;text-align:center;cursor:pointer;transition:all .25s}
.plan-card:hover{border-color:var(--accent);transform:translateY(-3px);box-shadow:0 8px 30px var(--accent-glow)}
.plan-card.recommended{border-color:#d4a017;box-shadow:0 0 0 1px #d4a017,0 4px 20px rgba(212,160,23,.15)}
.plan-recommend-tag{position:absolute;top:-10px;right:16px;padding:3px 12px;border-radius:10px;font-size:.7rem;font-weight:700;background:linear-gradient(135deg,#f59e0b,#d97706);color:#fff}
.plan-name{font-size:1.05rem;font-weight:700;color:var(--text);margin-bottom:8px}
.plan-price{font-size:1.6rem;font-weight:900;color:var(--accent);margin-bottom:6px}
.plan-desc{font-size:.82rem;color:var(--text2);margin-bottom:16px}
.plan-buy-btn{width:100%;padding:10px;border:none;border-radius:10px;background:linear-gradient(135deg,#6366f1,#4f46e5);color:#fff;font-size:.88rem;font-weight:600;cursor:pointer;font-family:inherit;transition:all .2s}
.plan-buy-btn:hover{box-shadow:0 4px 16px rgba(99,102,241,.4)}
.plan-card.recommended .plan-buy-btn{background:linear-gradient(135deg,#f59e0b,#d97706)}

/* View Tip Modal */
.view-tip-modal{width:400px;text-align:center}
.view-tip-text{font-size:.95rem;color:var(--text2);margin-bottom:20px;line-height:1.6}

/* Responsive */
@media(max-width:900px){
  .content{flex-direction:column}
  .sidebar{width:100%;position:static;max-height:none;display:flex;flex-wrap:wrap;gap:4px}
  .subject-group{margin-bottom:0}
  .grade-btn{padding:8px 14px}
  .hero h1{font-size:2rem}
}
@media(max-width:600px){
  .hero{padding:50px 20px 40px}
  .hero h1{font-size:1.6rem}
  .stats{gap:16px}
}