:root{
  --green-900:#0a1f14;
  --green-800:#0f2e1d;
  --green-700:#143d26;
  --green-600:#1b4d31;
  --green-500:#21613d;
  --green-400:#2d7a4e;
  --green-300:#4a9a6b;
  --green-100:#e8f3ec;
  --green-50:#f4f9f5;
  --white:#ffffff;
  --gray-50:#f8faf8;
  --gray-100:#eef2ee;
  --gray-200:#dde5de;
  --gray-400:#8aa096;
  --gray-600:#5a6b62;
  --gray-800:#2d3a33;
  --radius:14px;
  --shadow:0 8px 30px rgba(10,31,20,0.12);
  --shadow-lg:0 18px 50px rgba(10,31,20,0.18);
}
*{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Inter',sans-serif;background:var(--gray-50);color:var(--gray-800);overflow:hidden;height:100vh}
.app{display:flex;height:100vh}

/* SIDEBAR */
.sidebar{
  width:300px;min-width:300px;background:linear-gradient(180deg,var(--green-900) 0%,var(--green-800) 55%,var(--green-700) 100%);
  color:#fff;display:flex;flex-direction:column;padding:22px 16px;position:relative;overflow:hidden;
  border-right:1px solid rgba(255,255,255,0.07);
}
.sidebar::before{
  content:"";position:absolute;inset:0;
  background: radial-gradient(600px 300px at 20% 0%, rgba(74,154,107,0.18), transparent 60%),
              radial-gradient(400px 300px at 90% 30%, rgba(255,255,255,0.05), transparent 60%);
  pointer-events:none;
}
.sidebar-header{display:flex;align-items:center;justify-content:space-between;margin-bottom:28px;position:relative;z-index:1}
.logo{display:flex;align-items:center;gap:12px}
.logo-icon{width:44px;height:44px;background:rgba(255,255,255,0.12);border:1px solid rgba(255,255,255,0.15);backdrop-filter:blur(8px);border-radius:12px;display:grid;place-items:center;font-size:20px;color:#c8e6d3}
.logo-text h1{font-size:20px;font-weight:700;letter-spacing:-0.02em;line-height:1}
.logo-text span{font-size:11px;letter-spacing:0.12em;opacity:0.6;font-weight:600}
.sidebar-toggle{display:none;background:transparent;border:none;color:#fff;font-size:18px;cursor:pointer}
.sidebar-label{font-size:11px;letter-spacing:0.14em;font-weight:600;opacity:0.5;margin-bottom:10px;position:relative;z-index:1}
.category-list{display:flex;flex-direction:column;gap:6px;position:relative;z-index:1;flex:1;overflow-y:auto;padding-right:4px}
.category-list::-webkit-scrollbar{width:4px}
.category-list::-webkit-scrollbar-thumb{background:rgba(255,255,255,0.15);border-radius:20px}
.cat-item{
  display:flex;align-items:center;gap:10px;padding:11px 12px;border-radius:10px;cursor:pointer;
  border:1px solid transparent;transition:all .18s;font-size:14px;font-weight:500;color:rgba(255,255,255,0.85);
}
.cat-item:hover{background:rgba(255,255,255,0.07);border-color:rgba(255,255,255,0.08);color:#fff}
.cat-item.active{background:#fff;color:var(--green-800);box-shadow:0 4px 16px rgba(0,0,0,0.18);border-color:transparent;font-weight:600}
.cat-item.active .cat-icon{background:var(--green-700);color:#fff}
.cat-icon{width:32px;height:32px;border-radius:8px;background:rgba(255,255,255,0.10);display:grid;place-items:center;font-size:13px;flex-shrink:0}
.cat-item.active .cat-icon{background:var(--green-800)}
.cat-name{flex:1;white-space:nowrap;overflow:hidden;text-overflow:ellipsis}
.cat-count{font-size:11px;background:rgba(0,0,0,0.12);padding:3px 7px;border-radius:20px;min-width:22px;text-align:center}
.cat-item.active .cat-count{background:var(--green-100);color:var(--green-800)}
.cat-delete{opacity:0;transition:opacity .15s;background:transparent;border:none;color:inherit;font-size:12px;cursor:pointer;padding:4px}
.cat-item:hover .cat-delete{opacity:0.6}
.cat-delete:hover{opacity:1 !important;color:#c0392b}

.add-category-btn{
  margin-top:14px;position:relative;z-index:1;width:100%;padding:11px;border:1.5px dashed rgba(255,255,255,0.22);
  background:rgba(255,255,255,0.05);color:rgba(255,255,255,0.9);border-radius:10px;cursor:pointer;font-weight:600;font-size:13px;
  transition:all .18s;display:flex;align-items:center;justify-content:center;gap:8px;
}
.add-category-btn:hover{background:rgba(255,255,255,0.10);border-color:rgba(255,255,255,0.35);color:#fff}
.sidebar-footer{position:relative;z-index:1;margin-top:16px;padding-top:16px;border-top:1px solid rgba(255,255,255,0.08)}
.storage-status{display:flex;align-items:center;gap:8px;font-size:11px;opacity:0.6;margin-bottom:14px}
.storage-status i{font-size:10px}
.sidebar-quote{background:rgba(255,255,255,0.06);border:1px solid rgba(255,255,255,0.08);border-radius:12px;padding:12px}
.sidebar-quote p{font-family:'Amiri',serif;font-size:14px;line-height:1.4;color:#dbe9df}
.sidebar-quote span{font-size:11px;opacity:0.6}

/* MAIN */
.main{flex:1;display:flex;flex-direction:column;min-width:0;background:var(--gray-50)}
.topbar{
  height:64px;background:var(--white);border-bottom:1px solid var(--gray-200);
  display:flex;align-items:center;justify-content:space-between;padding:0 26px;gap:16px;flex-shrink:0;
}
.topbar-left{display:flex;align-items:center;gap:12px}
.mobile-menu-btn{display:none;width:36px;height:36px;border:1px solid var(--gray-200);background:var(--white);border-radius:8px;cursor:pointer}
.breadcrumb-category{font-weight:700;font-size:15px;color:var(--green-800)}
.breadcrumb-count{font-size:13px;color:var(--gray-400);margin-left:6px}
.topbar-right{display:flex;align-items:center;gap:12px}
.search-wrap{
  display:flex;align-items:center;gap:10px;background:var(--gray-50);border:1px solid var(--gray-200);
  padding:9px 12px;border-radius:10px;min-width:320px;transition:all .15s;
}
.search-wrap:focus-within{background:#fff;border-color:var(--green-400);box-shadow:0 0 0 3px rgba(45,122,78,0.12)}
.search-wrap i{color:var(--gray-400);font-size:13px}
.search-wrap input{flex:1;border:none;background:transparent;outline:none;font-size:13px;font-family:inherit;color:var(--gray-800)}
.search-wrap input::placeholder{color:var(--gray-400)}
.search-wrap kbd{font-size:10px;background:#fff;border:1px solid var(--gray-200);border-bottom-width:2px;padding:3px 6px;border-radius:6px;color:var(--gray-400);font-family:inherit}
.icon-btn{width:36px;height:36px;border:1px solid var(--gray-200);background:#fff;border-radius:8px;display:grid;place-items:center;cursor:pointer;color:var(--gray-600);transition:all .15s}
.icon-btn:hover{border-color:var(--green-400);color:var(--green-700)}

/* TOOLBAR */
.toolbar{
  background:#fff;border-bottom:1px solid var(--gray-200);padding:10px 22px;
  display:flex;align-items:center;gap:14px;flex-wrap:wrap;position:sticky;top:0;z-index:5;
}
.toolbar-group{display:flex;align-items:center;gap:6px}
.toolbar-divider{width:1px;height:24px;background:var(--gray-200)}
.tool-select{padding:7px 10px;border:1px solid var(--gray-200);border-radius:8px;background:var(--gray-50);font-size:13px;font-family:inherit;outline:none;cursor:pointer}
.tool-select.small{width:70px}
.tool-btn{width:34px;height:34px;border:1px solid transparent;background:transparent;border-radius:8px;display:grid;place-items:center;cursor:pointer;color:var(--gray-600);font-size:13px;transition:all .12s}
.tool-btn:hover{background:var(--gray-100);color:var(--green-800)}
.tool-btn.active{background:var(--green-800);color:#fff;border-color:var(--green-800)}
.color-picker{display:flex;align-items:center;gap:6px;padding:6px 8px;border:1px solid var(--gray-200);border-radius:8px;background:var(--gray-50);cursor:pointer;font-size:13px;color:var(--gray-600)}
.color-picker input{width:18px;height:18px;border:none;padding:0;background:transparent;cursor:pointer;border-radius:4px}
.toolbar-right{margin-left:auto;display:flex;align-items:center}
.autosave{font-size:11px;color:var(--green-400);display:flex;align-items:center;gap:6px;font-weight:600;letter-spacing:0.02em}
.autosave.saving{color:#d48800}

/* SHEET */
.sheet-container{flex:1;overflow-y:auto;padding:28px 28px 40px;background: radial-gradient(900px 500px at 50% 0%, #e6f0e8 0%, var(--gray-50) 60%);}
.sheet-container::-webkit-scrollbar{width:8px}
.sheet-container::-webkit-scrollbar-thumb{background:#c8d8cc;border-radius:20px}
.sheet{
  max-width:860px;margin:0 auto;background:#fff;border-radius:18px;box-shadow:var(--shadow-lg);
  border:1px solid var(--gray-200);padding:36px 42px;min-height:720px;
}
.sheet-header{margin-bottom:28px;padding-bottom:22px;border-bottom:1px solid var(--gray-100)}
.sheet-title{font-size:28px;font-weight:800;letter-spacing:-0.03em;color:var(--green-900);outline:none;border-radius:8px;padding:4px 6px;margin:-4px -6px;line-height:1.2}
.sheet-title:focus{background:var(--green-50);box-shadow:0 0 0 3px rgba(45,122,78,0.1)}
.sheet-subtitle{font-size:13px;color:var(--gray-400);margin-top:6px}
.chapters{display:flex;flex-direction:column;gap:0}
.chapter{
  padding:22px 0 26px;position:relative;
  border-bottom:1.5px solid rgba(15,46,29,0.08);
}
.chapter:last-child{border-bottom:none}
.chapter::after{
  content:"";position:absolute;bottom:-1px;left:0;right:0;height:1px;
  background:linear-gradient(90deg, transparent, rgba(15,46,29,0.06) 15%, rgba(15,46,29,0.06) 85%, transparent);
}
.chapter-header-row{display:flex;align-items:flex-start;gap:12px;margin-bottom:12px}
.chapter-number{width:28px;height:28px;border-radius:8px;background:var(--green-50);border:1px solid #d6e7db;color:var(--green-700);display:grid;place-items:center;font-size:12px;font-weight:700;flex-shrink:0;margin-top:2px}
.chapter-title{
  flex:1;font-size:18px;font-weight:700;color:var(--green-900);outline:none;border-radius:6px;padding:4px 8px;margin:-4px -8px;line-height:1.3;
  border:1px solid transparent;min-height:28px;
}
.chapter-title:focus{border-color:var(--green-300);background:var(--green-50)}
.chapter-title:empty:before{content:attr(data-placeholder);color:var(--gray-400);font-weight:500}
.chapter-actions{display:flex;gap:4px;opacity:0;transition:opacity .15s}
.chapter:hover .chapter-actions{opacity:1}
.chapter-actions button{width:28px;height:28px;border:1px solid var(--gray-200);background:#fff;border-radius:7px;display:grid;place-items:center;cursor:pointer;font-size:11px;color:var(--gray-600)}
.chapter-actions button:hover{border-color:#e0a0a0;color:#b03a2e}
.chapter-actions button.up:hover,.chapter-actions button.down:hover{border-color:var(--green-300);color:var(--green-700)}
.chapter-content{
  outline:none;min-height:48px;padding:8px 10px;margin:0 -10px;border-radius:8px;
  font-size:15px;line-height:1.7;color:#2a3a33;border:1px solid transparent;
}
.chapter-content:focus{border-color:#d6e7db;background:#fbfdfb}
.chapter-content:empty:before{content:attr(data-placeholder);color:#9ab0a5}
.chapter-content ul,.chapter-content ol{padding-left:22px;margin:8px 0}
.chapter-content blockquote{
  border-left:3.5px solid #2d7a4e;
  margin:14px 0;
  color:#3a4d42;
  font-style:italic;
  background:#f0f7f2;
  padding:12px 16px;
  border-radius:0 10px 10px 0;
  line-height:1.6;
}
.chapter-content blockquote + p{min-height:1.2em}
.chapter-content p{margin:6px 0}
.chapter-divider{
  height:1px;background:linear-gradient(90deg, transparent, rgba(255,255,255,0.6) 20%, rgba(15,46,29,0.08) 50%, rgba(255,255,255,0.6) 80%, transparent);
  margin:0 -42px;
}
.add-chapter-btn{
  margin-top:22px;width:100%;padding:14px;border:1.5px dashed #c8d8cc;background:#f4f9f5;color:var(--green-700);
  border-radius:12px;cursor:pointer;font-weight:600;font-size:14px;display:flex;align-items:center;justify-content:center;gap:8px;transition:all .15s;
}
.add-chapter-btn:hover{background:#e8f3ec;border-color:var(--green-400);color:var(--green-800)}
.sheet-spacer{height:40px}

/* MODAL */
.modal-overlay{position:fixed;inset:0;background:rgba(10,31,20,0.45);backdrop-filter:blur(6px);display:none;align-items:center;justify-content:center;z-index:50;padding:16px}
.modal-overlay.open{display:flex}
.modal{background:#fff;border-radius:16px;padding:22px;width:100%;max-width:420px;box-shadow:0 20px 60px rgba(0,0,0,0.25)}
.modal h3{font-size:16px;font-weight:700;color:var(--green-900);margin-bottom:14px}
.modal input{width:100%;padding:12px 14px;border:1.5px solid var(--gray-200);border-radius:10px;outline:none;font-size:14px;font-family:inherit}
.modal input:focus{border-color:var(--green-400);box-shadow:0 0 0 3px rgba(45,122,78,0.12)}
.modal-actions{display:flex;gap:10px;justify-content:flex-end;margin-top:16px}
.btn{padding:9px 16px;border-radius:9px;border:1px solid var(--gray-200);font-weight:600;font-size:13px;cursor:pointer;font-family:inherit}
.btn.ghost{background:#fff;color:var(--gray-600)}
.btn.primary{background:var(--green-800);color:#fff;border-color:var(--green-800)}
.btn.primary:hover{background:var(--green-900)}

/* highlight */
mark{background:#fff3a6;padding:1px 3px;border-radius:4px}

/* responsive */
@media(max-width:900px){
  .sidebar{position:fixed;left:0;top:0;bottom:0;z-index:30;transform:translateX(-100%);transition:transform .25s;width:300px;min-width:300px}
  .sidebar.open{transform:translateX(0)}
  .sidebar-toggle,.mobile-menu-btn{display:grid}
  .search-wrap{min-width:180px}
  .search-wrap kbd{display:none}
  .sheet{padding:22px 18px}
  .topbar{padding:0 14px}
  .sheet-container{padding:16px}
  .toolbar{padding:10px 12px;gap:8px}
}