/* ═══════════════════════════════════════════
   KTU Notes — Main CSS (Public Site)
═══════════════════════════════════════════ */
:root {
  --primary: #1a56db;
  --primary-dark: #1341a8;
  --accent: #f59e0b;
  --bg: #f8fafc;
  --surface: #ffffff;
  --border: #e2e8f0;
  --text: #1e293b;
  --text-muted: #64748b;
  --success: #10b981;
  --radius: 12px;
  --shadow: 0 1px 3px rgba(0,0,0,.08), 0 4px 16px rgba(0,0,0,.06);
  --shadow-lg: 0 8px 32px rgba(0,0,0,.12);
  --c1:#6366f1;--c2:#8b5cf6;--c3:#ec4899;--c4:#1a56db;
  --c5:#f59e0b;--c6:#10b981;--c7:#ef4444;--c8:#0ea5e9;
  font-size: 16px;
}
*,*::before,*::after{box-sizing:border-box;margin:0;padding:0}
body{font-family:'Inter',sans-serif;background:var(--bg);color:var(--text);line-height:1.65;-webkit-font-smoothing:antialiased}
a{color:inherit;text-decoration:none}
img{max-width:100%;height:auto}

/* ── Container ── */
.container{max-width:1200px;margin:0 auto;padding:0 20px}
.page-container{padding-top:40px;padding-bottom:80px}

/* ── Header ── */
.site-header{background:var(--surface);border-bottom:1px solid var(--border);position:sticky;top:0;z-index:100;box-shadow:0 1px 8px rgba(0,0,0,.06)}
.header-inner{display:flex;align-items:center;justify-content:space-between;height:64px}
.logo{display:flex;align-items:center;gap:10px;font-size:1.3rem;font-weight:800;letter-spacing:-0.5px}
.logo-icon{font-size:1.5rem}
.logo-text{color:var(--text)}
.logo-accent{color:var(--primary)}
.main-nav{display:flex;gap:8px;align-items:center}
.nav-link{padding:7px 16px;border-radius:8px;font-weight:500;color:var(--text-muted);font-size:.9rem;transition:all .15s}
.nav-link:hover{background:var(--bg);color:var(--primary)}
.hamburger{display:none;flex-direction:column;gap:5px;background:none;border:none;cursor:pointer;padding:4px}
.hamburger span{display:block;width:22px;height:2px;background:var(--text);border-radius:2px;transition:all .2s}
.hamburger.active span:nth-child(1){transform:rotate(45deg) translate(5px,5px)}
.hamburger.active span:nth-child(2){opacity:0}
.hamburger.active span:nth-child(3){transform:rotate(-45deg) translate(5px,-5px)}

/* ── Hero ── */
.hero{background:linear-gradient(135deg,#0f172a 0%,#1e293b 50%,#1a3a6e 100%);color:#fff;padding:80px 0 70px;text-align:center}
.hero-badge{display:inline-block;background:rgba(255,255,255,.12);border:1px solid rgba(255,255,255,.2);border-radius:20px;padding:5px 16px;font-size:.8rem;font-weight:600;letter-spacing:.5px;margin-bottom:20px;text-transform:uppercase}
.hero-title{font-size:clamp(2rem,5vw,3.2rem);font-weight:800;line-height:1.2;margin-bottom:16px;letter-spacing:-1px}
.gradient-text{background:linear-gradient(90deg,#60a5fa,#a78bfa);-webkit-background-clip:text;-webkit-text-fill-color:transparent;background-clip:text}
.hero-subtitle{font-size:1.1rem;color:rgba(255,255,255,.75);max-width:600px;margin:0 auto 36px}
.hero-search{display:flex;gap:0;max-width:560px;margin:0 auto;border-radius:12px;overflow:hidden;box-shadow:var(--shadow-lg)}
.search-input{flex:1;padding:16px 20px;border:none;font-size:1rem;font-family:'Inter',sans-serif;outline:none}
.search-btn{padding:16px 28px;background:var(--primary);color:#fff;border:none;font-weight:700;font-size:.95rem;cursor:pointer;transition:background .15s}
.search-btn:hover{background:var(--primary-dark)}

/* ── Semester Section ── */
.semester-section{padding:60px 0 40px}
.scheme-toggle{display:flex;gap:8px;margin-bottom:36px;justify-content:center}
.scheme-btn{padding:10px 28px;border-radius:8px;border:2px solid var(--border);background:var(--surface);font-weight:600;cursor:pointer;font-family:'Inter',sans-serif;font-size:.95rem;transition:all .15s}
.scheme-btn.active{background:var(--primary);color:#fff;border-color:var(--primary)}
.semester-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:16px}
.hidden{display:none!important}
.sem-card{display:flex;flex-direction:column;align-items:center;justify-content:center;padding:32px 20px;background:var(--surface);border-radius:var(--radius);border:2px solid var(--border);cursor:pointer;transition:all .2s;text-align:center;gap:6px}
.sem-card:hover{border-color:var(--accent);box-shadow:var(--shadow-lg);transform:translateY(-3px)}
.sem-label{font-size:2rem;font-weight:800;color:var(--accent)}
.sem-sub{font-size:.8rem;color:var(--text-muted);font-weight:500}

/* ── Branches Section ── */
.branches-section{background:var(--surface);padding:60px 0}
.section-title{font-size:1.6rem;font-weight:700;margin-bottom:32px;text-align:center;letter-spacing:-0.5px}
.branches-grid{display:flex;gap:16px;justify-content:center;flex-wrap:wrap}
.branch-card{display:flex;flex-direction:column;align-items:center;gap:10px;padding:28px 36px;background:var(--bg);border-radius:var(--radius);border:2px solid var(--border);transition:all .2s;min-width:140px;text-align:center}
.branch-card:hover{border-color:var(--primary);background:var(--primary);color:#fff;transform:translateY(-3px);box-shadow:var(--shadow-lg)}
.branch-icon{font-size:2rem}
.branch-name{font-weight:600;font-size:.9rem}

/* ── Features Section ── */
.features-section{padding:60px 0}
.features-grid{display:grid;grid-template-columns:repeat(4,1fr);gap:20px}
.feature-card{background:var(--surface);padding:28px;border-radius:var(--radius);border:1px solid var(--border);text-align:center}
.feature-icon{font-size:2.2rem;display:block;margin-bottom:14px}
.feature-card h3{font-size:1rem;font-weight:700;margin-bottom:8px}
.feature-card p{font-size:.9rem;color:var(--text-muted);line-height:1.5}

/* ── Breadcrumb ── */
.breadcrumb{display:flex;gap:6px;align-items:center;font-size:.85rem;color:var(--text-muted);margin-bottom:24px;flex-wrap:wrap}
.breadcrumb a{color:var(--primary)}
.breadcrumb a:hover{text-decoration:underline}

/* ── Page Titles ── */
.page-title{font-size:clamp(1.4rem,3vw,2rem);font-weight:800;letter-spacing:-0.5px;margin-bottom:8px}
.page-subtitle{color:var(--text-muted);margin-bottom:32px;font-size:1rem}
.section-heading{font-size:1.1rem;font-weight:700;margin:36px 0 16px;display:flex;align-items:center;gap:8px}

/* ── Branch Select ── */
.branch-select-grid{display:grid;gap:12px;margin-bottom:40px}
.branch-select-card{display:flex;align-items:center;gap:16px;padding:20px 24px;background:var(--surface);border-radius:var(--radius);border:1px solid var(--border);transition:all .15s}
.branch-select-card:hover{border-color:var(--primary);box-shadow:var(--shadow)}
.branch-select-icon{font-size:2rem}
.branch-select-name{font-weight:600;font-size:1rem}
.branch-select-code{font-size:.8rem;color:var(--text-muted);margin-top:2px}
.branch-select-card .arrow{margin-left:auto;color:var(--text-muted);font-size:1.2rem}
.scheme-switch-block{display:flex;align-items:center;gap:16px;color:var(--text-muted);margin-top:32px;font-size:.9rem}

/* ── Subject Grid ── */
.subjects-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(280px,1fr));gap:16px}
.subject-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;transition:all .2s}
.subject-card:hover{border-color:var(--primary);box-shadow:var(--shadow);transform:translateY(-2px)}
.subject-code{font-size:.8rem;font-weight:700;color:var(--primary);background:#eff6ff;padding:3px 10px;border-radius:20px;display:inline-block;margin-bottom:10px}
.subject-name{font-weight:700;font-size:1rem;margin-bottom:6px}
.subject-meta{font-size:.8rem;color:var(--text-muted);margin-bottom:12px}
.subject-links{display:flex;gap:6px;flex-wrap:wrap}
.tag{background:var(--bg);border:1px solid var(--border);border-radius:20px;padding:2px 10px;font-size:.75rem;color:var(--text-muted)}

/* ── Subject Header ── */
.subject-header{margin-bottom:36px}
.subject-code-badge{display:inline-block;background:var(--primary);color:#fff;padding:4px 14px;border-radius:20px;font-weight:700;font-size:.85rem;margin-bottom:12px}
.subject-desc{color:var(--text-muted);margin-top:8px;font-size:.95rem;max-width:640px}



/* ── Modules Grid ── */
.modules-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(200px,1fr));gap:12px;margin-bottom:36px}
.module-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;transition:all .2s;display:block}
.module-card:hover{border-color:var(--primary);box-shadow:var(--shadow);transform:translateY(-2px)}
.module-card-empty{opacity:.6}
.module-num{display:block;font-size:.8rem;font-weight:700;color:var(--primary);margin-bottom:6px}
.module-title{display:block;font-weight:600;font-size:.9rem}
.tag-pdf{background:#fef3c7;color:#92400e;border:none;margin-top:8px;display:inline-block}

/* ── Content Type Grid ── */
.content-type-grid{display:grid;gap:12px}
.content-type-card{display:flex;align-items:center;gap:16px;padding:18px 24px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);transition:all .15s}
.content-type-card:hover{border-color:var(--primary);box-shadow:var(--shadow)}
.ct-icon{font-size:1.8rem}
.ct-title{font-weight:700;font-size:.95rem}
.ct-desc{font-size:.8rem;color:var(--text-muted)}
.content-type-card .arrow{margin-left:auto;color:var(--text-muted)}

/* ── Module Page Layout ── */
.module-page{padding:0 0 80px}
.module-layout{display:grid;grid-template-columns:260px 1fr;gap:40px;padding-top:40px;align-items:start}
.module-sidebar{position:sticky;top:80px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px;max-height:calc(100vh - 100px);overflow-y:auto}
.sidebar-course-title{font-weight:700;font-size:.85rem;color:var(--text-muted);padding-bottom:12px;border-bottom:1px solid var(--border);margin-bottom:12px;line-height:1.4}
.module-nav{display:flex;flex-direction:column;gap:4px}
.module-nav-link{display:block;padding:8px 12px;border-radius:8px;font-size:.875rem;font-weight:500;color:var(--text-muted);transition:all .15s}
.module-nav-link:hover{background:var(--bg);color:var(--primary)}
.module-nav-link.active{background:#eff6ff;color:var(--primary);font-weight:600}
.nav-divider{border:none;border-top:1px solid var(--border);margin:8px 0}
.module-content{min-width:0}
.module-title{font-size:clamp(1.3rem,3vw,1.8rem);font-weight:800;letter-spacing:-0.5px;margin-bottom:10px;line-height:1.3}
.module-subtitle-inline{font-size:1rem;font-weight:500;color:var(--text-muted)}
.module-meta-bar{display:flex;gap:8px;flex-wrap:wrap;margin-bottom:32px}
.meta-tag{background:var(--bg);border:1px solid var(--border);border-radius:20px;padding:4px 12px;font-size:.78rem;font-weight:600;color:var(--text-muted)}

/* ── Key Concepts & Bullets ── */
.key-concepts-box,.bullet-box{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:24px;margin-bottom:28px}
.key-concepts-box{border-left:4px solid var(--primary)}
.bullet-box{border-left:4px solid var(--accent)}
.box-title{font-size:1rem;font-weight:700;margin-bottom:14px}
.concept-list,.bullet-list{padding-left:20px;display:flex;flex-direction:column;gap:6px}
.concept-list li,.bullet-list li{font-size:.92rem;color:var(--text)}

/* ── Notes Content ── */
.notes-content{line-height:1.8;font-size:.97rem}
.notes-content h2{font-size:1.3rem;font-weight:700;margin:36px 0 12px;color:var(--text);border-bottom:2px solid var(--border);padding-bottom:8px}
.notes-content h3{font-size:1.1rem;font-weight:700;margin:24px 0 10px;color:var(--primary)}
.notes-content p{margin-bottom:16px;color:var(--text)}
.notes-content ul,.notes-content ol{margin:0 0 16px 24px}
.notes-content li{margin-bottom:6px}
.notes-content strong{color:var(--text)}
.notes-content table{width:100%;border-collapse:collapse;margin-bottom:20px;font-size:.9rem}
.notes-content th,.notes-content td{border:1px solid var(--border);padding:8px 12px;text-align:left}
.notes-content th{background:var(--bg);font-weight:600}

/* ── PDF Download ── */
.pdf-download-card{display:flex;align-items:center;gap:20px;background:#fff7ed;border:1px solid #fed7aa;border-radius:var(--radius);padding:20px 24px;margin:32px 0}
.pdf-icon{font-size:2.5rem}
.pdf-title{font-weight:700;font-size:.95rem;margin-bottom:4px}
.pdf-desc{font-size:.82rem;color:var(--text-muted)}
.btn-download{margin-left:auto;background:var(--accent);color:#fff;padding:10px 20px;border-radius:8px;font-weight:700;font-size:.875rem;white-space:nowrap;transition:all .15s}
.btn-download:hover{background:#d97706;transform:translateY(-1px)}

/* ── Module Page Nav ── */
.module-page-nav{display:flex;justify-content:space-between;margin-top:48px;padding-top:24px;border-top:1px solid var(--border)}
.nav-prev,.nav-next{display:inline-flex;align-items:center;gap:8px;padding:10px 20px;background:var(--surface);border:1px solid var(--border);border-radius:8px;font-weight:600;font-size:.9rem;transition:all .15s}
.nav-prev:hover,.nav-next:hover{border-color:var(--primary);color:var(--primary)}

/* ── IQ / PYQ / Revision ── */
.iq-list{display:flex;flex-direction:column;gap:16px}
.iq-item{display:flex;gap:16px;align-items:flex-start;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:18px}
.iq-num{background:var(--primary);color:#fff;border-radius:50%;width:30px;height:30px;display:flex;align-items:center;justify-content:center;font-size:.78rem;font-weight:700;flex-shrink:0}
.iq-question{display:block;font-weight:600;font-size:.95rem;margin-bottom:4px}
.iq-module-tag,.iq-marks-tag{font-size:.75rem;background:var(--bg);border:1px solid var(--border);border-radius:12px;padding:2px 10px;margin-right:6px;color:var(--text-muted)}
.iq-answer{margin-top:10px;font-size:.9rem;color:var(--text-muted);border-top:1px solid var(--border);padding-top:10px}
.pyq-year-block{margin-bottom:40px}
.pyq-year-title{font-size:1.2rem;font-weight:700;margin-bottom:12px}
.pyq-list{padding-left:20px;display:flex;flex-direction:column;gap:8px;margin-top:12px}
.pyq-list li{font-size:.93rem}
.revision-grid{display:grid;grid-template-columns:repeat(auto-fill,minmax(260px,1fr));gap:16px}
.revision-card{background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);padding:20px}
.revision-topic{font-size:1rem;font-weight:700;margin-bottom:10px;color:var(--primary)}
.revision-points{padding-left:20px;display:flex;flex-direction:column;gap:6px}
.revision-points li{font-size:.9rem}

/* ── Search Page ── */
.search-form{margin-bottom:28px}
.search-input-lg{width:100%;padding:16px 20px;border:2px solid var(--border);border-radius:12px;font-size:1rem;font-family:'Inter',sans-serif;outline:none;transition:border .15s}
.search-input-lg:focus{border-color:var(--primary)}
.search-results{display:flex;flex-direction:column;gap:10px}
.search-result-card{display:flex;align-items:center;gap:16px;padding:16px 20px;background:var(--surface);border:1px solid var(--border);border-radius:var(--radius);transition:all .15s}
.search-result-card:hover{border-color:var(--primary);box-shadow:var(--shadow)}
.result-code{background:var(--primary);color:#fff;padding:4px 12px;border-radius:20px;font-size:.8rem;font-weight:700;white-space:nowrap}
.result-name{font-weight:600;font-size:.95rem}
.result-meta{font-size:.8rem;color:var(--text-muted);margin-top:2px}
.search-result-card .arrow{margin-left:auto;color:var(--text-muted)}

/* ── Empty State ── */
.empty-state{text-align:center;padding:80px 20px;color:var(--text-muted)}
.empty-icon{font-size:3rem;display:block;margin-bottom:16px}
.empty-hint{font-size:.85rem;margin-top:8px}
.empty-state h2{font-size:1.3rem;font-weight:700;color:var(--text);margin-bottom:8px}

/* ── Footer ── */
.site-footer{background:#0f172a;color:#94a3b8;padding:60px 0 0}
.footer-inner{display:grid;grid-template-columns:1fr 1fr;gap:40px}
.footer-brand p{margin-top:10px;font-size:.875rem;line-height:1.6;max-width:280px}
.footer-brand .logo-text{color:#fff}
.footer-links{display:grid;grid-template-columns:repeat(3,1fr);gap:20px}
.footer-col h4{color:#e2e8f0;font-weight:700;font-size:.85rem;margin-bottom:12px;text-transform:uppercase;letter-spacing:.5px}
.footer-col a{display:block;font-size:.83rem;padding:3px 0;color:#64748b;transition:color .15s}
.footer-col a:hover{color:#60a5fa}
.footer-bottom{border-top:1px solid #1e293b;margin-top:40px;padding:20px 0;text-align:center;font-size:.8rem}

/* ── Buttons ── */
.btn-primary{display:inline-block;background:var(--primary);color:#fff;padding:12px 24px;border-radius:8px;font-weight:700;font-size:.9rem;border:none;cursor:pointer;transition:all .15s;font-family:'Inter',sans-serif}
.btn-primary:hover{background:var(--primary-dark);transform:translateY(-1px)}
.btn-outline{display:inline-block;background:transparent;color:var(--primary);padding:10px 20px;border-radius:8px;font-weight:600;font-size:.9rem;border:2px solid var(--primary);transition:all .15s}
.btn-outline:hover{background:var(--primary);color:#fff}

/* ── PDF & HTML Notes Layouts ── */
.meta-tag-type { background: var(--primary); color: #fff; border-color: var(--primary); }
.meta-tag-type.meta-tag-pdf { background: #dc2626; border-color: #dc2626; }
.meta-tag-type.meta-tag-html { background: #059669; border-color: #059669; }

.pdf-viewer-section { margin-bottom: 40px; }
.pdf-download-bar { display: flex; align-items: center; justify-content: space-between; gap: 20px; background: #fff1f2; border: 1px solid #fecdd3; border-radius: var(--radius) var(--radius) 0 0; padding: 20px 24px; }
.pdf-file-info { display: flex; align-items: center; gap: 16px; }
.pdf-big-icon { font-size: 2.5rem; }
.pdf-file-name { font-weight: 700; font-size: .95rem; color: #881337; margin-bottom: 2px; }
.pdf-file-meta { font-size: .82rem; color: #be123c; }
.pdf-embed-wrapper { width: 100%; height: 75vh; min-height: 600px; border: 1px solid var(--border); border-top: none; border-radius: 0 0 var(--radius) var(--radius); overflow: hidden; background: #f1f5f9; }
.pdf-embed { width: 100%; height: 100%; border: none; }
.pdf-fallback { display: none; text-align: center; padding: 20px; background: var(--surface); border: 1px solid var(--border); border-top: none; font-size: .9rem; border-radius: 0 0 var(--radius) var(--radius); }

.html-download-bar { display: flex; align-items: center; justify-content: space-between; flex-wrap: wrap; gap: 16px; padding: 16px 20px; background: #ecfdf5; border: 1px solid #a7f3d0; border-radius: var(--radius); margin-bottom: 24px; }
.html-download-info { font-weight: 600; font-size: .9rem; color: #065f46; display: flex; align-items: center; gap: 8px; }
.btn-download-html { background: #059669; color: #fff; padding: 10px 20px; border-radius: 8px; font-weight: 700; font-size: .875rem; white-space: nowrap; transition: all .15s; border: none; cursor: pointer; text-decoration: none; display: inline-block; }
.btn-download-html:hover { background: #047857; transform: translateY(-1px); color: #fff; }

/* ── Scanned Digital Notes ── */
.digital-notes-container { display: flex; flex-direction: column; align-items: center; gap: 16px; background: #f1f5f9; padding: 24px; border: 1px solid var(--border); border-radius: var(--radius); }
.scanned-page-img { max-width: 100%; height: auto; box-shadow: var(--shadow); border-radius: 4px; border: 1px solid #cbd5e1; }

/* ── Error Page ── */
.error-page{text-align:center;padding:100px 20px}
.error-code{font-size:7rem;font-weight:800;color:var(--border);line-height:1;margin-bottom:16px}
.error-page h1{font-size:1.8rem;font-weight:700;margin-bottom:12px}
.error-page p{color:var(--text-muted);margin-bottom:28px}

/* ── Responsive ── */
@media(max-width:900px){
  .module-layout{grid-template-columns:1fr}
  .module-sidebar{position:static;max-height:none}
  .features-grid{grid-template-columns:repeat(2,1fr)}
  .footer-inner{grid-template-columns:1fr}
  .footer-links{grid-template-columns:repeat(3,1fr)}
}
@media(max-width:640px){
  .semester-grid{grid-template-columns:repeat(2,1fr)}
  .features-grid{grid-template-columns:1fr}
  .hero{padding:60px 0 50px}
  .hero-search{flex-direction:column;border-radius:12px}
  .search-input{border-radius:10px}
  .search-btn{border-radius:10px;padding:14px}
  .main-nav{display:none;position:fixed;top:64px;left:0;right:0;background:var(--surface);border-bottom:1px solid var(--border);flex-direction:column;padding:16px;gap:4px;z-index:99}
  .main-nav.open{display:flex}
  .hamburger{display:flex}
  .footer-links{grid-template-columns:repeat(2,1fr)}
  .subjects-grid{grid-template-columns:1fr}
  .pdf-download-card{flex-wrap:wrap}
  .btn-download{margin-left:0;width:100%;text-align:center}
  .pdf-download-bar { flex-direction: column; align-items: flex-start; }
  .pdf-embed-wrapper { display: none; }
  .pdf-fallback { display: block; }
}