:root{--sr-navy:#0b1f3a;--sr-blue:#0b7cff;--sr-cyan:#20bdf5;--sr-bg:#f5f9ff;--sr-panel:#fff;--sr-line:#dce7f2;--sr-text:#142942;--sr-muted:#70839a}*{box-sizing:border-box}html{background:var(--sr-bg)}body.secure-tutorial-reader-page{margin:0;background:var(--sr-bg);color:var(--sr-text);font-family:Inter,Segoe UI,Arial,sans-serif}.secure-reader{min-height:100vh;display:grid;grid-template-columns:300px minmax(0,1fr)}.secure-reader-sidebar{position:sticky;top:0;height:100vh;overflow:auto;padding:20px 16px;border-right:1px solid var(--sr-line);background:linear-gradient(180deg,#0b1f3a,#0d2948);color:#fff}.secure-reader-brand{display:flex;align-items:center;gap:10px;color:#fff;text-decoration:none}.secure-reader-brand img{width:40px;height:40px}.secure-reader-brand b{display:block;font-size:18px}.secure-reader-brand b span{color:#4fb9ff}.secure-reader-brand small{display:block;margin-top:2px;color:#9db4cb;font-size:10px}.secure-reader-course-meta{margin-top:26px;padding:16px;border:1px solid rgba(255,255,255,.08);border-radius:14px;background:rgba(255,255,255,.05)}.secure-reader-course-meta>span{font-size:8px;font-weight:900;letter-spacing:.14em;color:#67d7ff}.secure-reader-course-meta h2{margin:8px 0 6px;font-size:18px}.secure-reader-course-meta p{margin:0;color:#b9c9d9;font-size:11px;line-height:1.55}.secure-reader-nav{display:grid;gap:5px;margin-top:16px}.secure-reader-nav a{display:flex;gap:10px;align-items:flex-start;padding:10px 11px;border-radius:10px;color:#c8d5e3;text-decoration:none;font-size:11px;line-height:1.35}.secure-reader-nav a:hover,.secure-reader-nav a.active{background:rgba(11,124,255,.18);color:#fff}.secure-reader-nav b{min-width:24px;color:#66d0ff}.secure-reader-back{display:inline-block;margin:18px 8px 0;color:#9db4cb;text-decoration:none;font-size:10px;font-weight:800}.secure-reader-main{min-width:0}.secure-reader-toolbar{position:sticky;top:0;z-index:20;min-height:58px;display:flex;align-items:center;gap:10px;padding:10px 18px;border-bottom:1px solid var(--sr-line);background:rgba(255,255,255,.96);backdrop-filter:blur(16px)}.secure-reader-menu-button{display:none}.secure-reader-toolbar>a{margin-left:auto;color:#42627f;text-decoration:none;font-size:10px;font-weight:850}.secure-reader-security{display:flex;align-items:center;gap:8px;color:#60768f;font-size:10px;font-weight:800}.secure-reader-security i{width:8px;height:8px;border-radius:50%;background:#34c98c;box-shadow:0 0 0 4px rgba(52,201,140,.12)}.secure-reader-save-actions{display:flex;align-items:center;gap:7px;margin-left:auto}.secure-reader-save-button{min-height:34px;display:inline-flex;align-items:center;justify-content:center;padding:0 11px;border:1px solid #d5e2ef;border-radius:9px;background:#fff;color:#31516f;font-size:10px;font-weight:850;cursor:pointer;transition:.16s ease}.secure-reader-save-button:hover:not(:disabled){transform:translateY(-1px);border-color:#b8d2ea;background:#f7fbff;color:#0b5dc7}.secure-reader-save-button:disabled{opacity:.5;cursor:not-allowed}.secure-reader-language{display:flex;align-items:center;gap:8px;color:#4c647c;font-size:11px;font-weight:750}.secure-reader-language select{min-height:34px;border:1px solid #d5e2ef;border-radius:9px;background:#fff;color:#31516f;padding:0 9px;font:inherit}.secure-reader-article{width:min(980px,calc(100% - 44px));margin:0 auto;padding:38px 0 70px}.secure-reader-article .lesson-title{font-size:clamp(36px,5vw,58px);letter-spacing:-1.8px}.secure-reader-article .lesson-body{font-size:16px;line-height:1.75}.secure-reader-article .lesson-body pre{overflow:auto}.secure-reader-loading,.secure-reader-error{min-height:55vh;display:grid;place-items:center;text-align:center;color:var(--sr-muted)}.secure-reader-loading span{width:32px;height:32px;border:3px solid #dce9f5;border-top-color:var(--sr-blue);border-radius:50%;animation:srspin .8s linear infinite}.secure-reader-loading strong{margin-top:-120px}.secure-reader-error>div{max-width:520px;padding:28px;border:1px solid var(--sr-line);border-radius:16px;background:#fff}.secure-reader-error h2{margin-top:0;color:var(--sr-text)}.secure-reader-error a{display:inline-flex;margin-top:10px;padding:10px 14px;border-radius:10px;background:var(--sr-blue);color:#fff;text-decoration:none;font-size:11px;font-weight:850}@keyframes srspin{to{transform:rotate(360deg)}}@media(max-width:1080px){.secure-reader-security span{display:none}.secure-reader-save-button{padding:0 9px}.secure-reader-toolbar>a{display:none}}@media(max-width:900px){.secure-reader{grid-template-columns:1fr}.secure-reader-sidebar{position:fixed;left:0;top:0;z-index:30;width:min(320px,88vw);transform:translateX(-105%);transition:.2s ease;box-shadow:20px 0 50px rgba(11,31,58,.22)}.secure-reader-sidebar.open{transform:translateX(0)}.secure-reader-menu-button{display:inline-flex;min-height:34px;align-items:center;padding:0 10px;border:1px solid #d5e2ef;border-radius:9px;background:#fff;color:#31516f;font-weight:800}.secure-reader-save-actions{margin-left:0}.secure-reader-article{width:min(100% - 28px,980px);padding-top:28px}}@media(max-width:680px){.secure-reader-toolbar{flex-wrap:wrap}.secure-reader-language{order:3;width:100%;justify-content:flex-end}.secure-reader-save-actions{margin-left:auto}.secure-reader-save-button{font-size:9px}}