/* ============================================================
    BASE & RESET
============================================================ */
*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }

:root {
    --bg:        #0d0f18;
    --surface:   #13151f;
    --surface2:  #1a1d2e;
    --border:    rgba(255,255,255,0.07);
    --text:      #eef0f6;
    --muted:     #8b8fa8;
    --green:     #a3e635;
    --green-dim: rgba(163,230,53,0.12);
    --green-glow:rgba(163,230,53,0.25);
    --accent:    #60a5fa;
    --red:       #f87171;
    --yellow:    #fbbf24;
    --radius:    14px;
    --radius-lg: 22px;
}

html { scroll-behavior: smooth; }

body {
    background: var(--bg);
    color: var(--text);
    font-family: 'DM Sans', sans-serif;
    font-size: 15px;
    line-height: 1.65;
    overflow-x: hidden;
    min-height: 100vh;
}

a { color: inherit; text-decoration: none; }
ul { list-style: none; }

/* ============================================================
    BACKGROUND ORBS
============================================================ */
.bg-orb {
    position: fixed;
    border-radius: 50%;
    filter: blur(80px);
    pointer-events: none;
    z-index: 0;
    opacity: 0.5;
}
.orb1 { width: 500px; height: 500px; background: radial-gradient(circle, rgba(163,230,53,0.15), transparent 70%); top: -100px; right: -100px; animation: orbFloat 12s ease-in-out infinite; }
.orb2 { width: 400px; height: 400px; background: radial-gradient(circle, rgba(96,165,250,0.1), transparent 70%); bottom: 200px; left: -150px; animation: orbFloat 16s ease-in-out infinite reverse; }
.orb3 { width: 300px; height: 300px; background: radial-gradient(circle, rgba(251,191,36,0.08), transparent 70%); top: 50%; left: 50%; animation: orbFloat 20s ease-in-out infinite; }

@keyframes orbFloat {
    0%, 100% { transform: translate(0,0) scale(1); }
    33%       { transform: translate(30px,-20px) scale(1.05); }
    66%       { transform: translate(-20px,15px) scale(0.97); }
}

/* ============================================================
    NAVBAR
============================================================ */
.navbar {
    position: fixed; top: 0; left: 0; right: 0; z-index: 1000;
    display: flex; align-items: center; justify-content: space-between;
    padding: 0 5%;
    height: 64px;
    background: rgba(13,15,24,0.7);
    backdrop-filter: blur(16px);
    border-bottom: 1px solid var(--border);
    transition: background 0.3s;
}
.navbar.scrolled { background: rgba(13,15,24,0.95); }

.nav-logo { display: flex; align-items: center; gap: 8px; font-family: 'Syne', sans-serif; font-weight: 700; font-size: 1.15rem; }
.logo-icon { font-size: 1.3rem; }
.accent { color: var(--green); }

.nav-links { display: flex; align-items: center; gap: 4px; }
.nav-links li { display: flex; }
.nav-link { padding: 6px 13px; border-radius: 8px; font-size: 0.88rem; font-weight: 500; color: var(--muted); transition: color 0.2s, background 0.2s; }
.nav-link:hover { color: var(--text); background: rgba(255,255,255,0.06); }

.nav-yt-btn {
    display: flex; align-items: center; gap: 6px;
    gap: 6px; padding: 7px 14px;
    border-radius: 8px;
    background: rgba(239,68,68,0.12);
    border: 1px solid rgba(239,68,68,0.25);
    color: #f87171; font-size: 0.85rem; font-weight: 600;
    transition: background 0.2s, border-color 0.2s;
}
.nav-yt-btn:hover { background: rgba(239,68,68,0.22); border-color: rgba(239,68,68,0.5); }

.hamburger { display: none; flex-direction: column; gap: 5px; background: none; border: none; cursor: pointer; padding: 6px; }
.hamburger span { display: block; width: 22px; height: 2px; background: var(--text); border-radius: 2px; transition: transform 0.3s, opacity 0.3s; }

@media (max-width: 768px) {
    .nav-links { display: none; position: fixed; top: 64px; left: 0; right: 0; flex-direction: column; gap: 0; background: rgba(13,15,24,0.98); padding: 16px 0; border-bottom: 1px solid var(--border); }
    .nav-links.open { display: flex; }
    .nav-links li { width: 100%; }
    .nav-link { padding: 12px 24px; border-radius: 0; display: block; }
    .nav-yt-btn { margin: 8px 24px; border-radius: 8px; }
    .hamburger { display: flex; }
}
.paper-hero {
    position: relative; z-index: 1;
    padding: 110px 5% 60px;
}

.paper-breadcrumb {
    display: flex; align-items: center; gap: 8px;
    font-size: 0.82rem; color: var(--muted);
    margin-bottom: 28px;
}
.paper-breadcrumb a { color: var(--muted); transition: color 0.2s; }
.paper-breadcrumb a:hover { color: var(--green); }
.paper-breadcrumb span { color: var(--border); }

.paper-hero-inner { display: flex; align-items: flex-start; gap: 40px; flex-wrap: wrap; }

.paper-hero-left { flex: 1; min-width: 280px; }

.hero-badge {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 6px 14px; border-radius: 20px;
    background: var(--green-dim); border: 1px solid rgba(163,230,53,0.2);
    font-size: 0.78rem; font-weight: 600; color: var(--green);
    margin-bottom: 18px; letter-spacing: 0.03em; text-transform: uppercase;
}

.paper-title {
    font-family: 'Syne', sans-serif;
    font-size: clamp(2rem, 5vw, 3.4rem);
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 14px;
}

.hero-highlight {
    background: linear-gradient(135deg, var(--green) 0%, #86efac 100%);
    -webkit-background-clip: text; -webkit-text-fill-color: transparent;
    background-clip: text;
}

.paper-sub { color: var(--muted); font-size: 1rem; margin-bottom: 22px; }

.paper-meta-pills { display: flex; flex-wrap: wrap; gap: 8px; }
.paper-meta-pills span {
    padding: 5px 13px; border-radius: 20px;
    background: var(--surface2); border: 1px solid var(--border);
    font-size: 0.8rem; font-weight: 500; color: var(--muted);
}

.paper-hero-right { flex-shrink: 0; }

.paper-subject-card {
    background: var(--surface2);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px 40px;
    text-align: center;
    min-width: 220px;
}
.psc-icon { font-size: 3rem; margin-bottom: 12px; }
.psc-name { font-family: 'Syne', sans-serif; font-weight: 700; font-size: 0.95rem; color: var(--text); }

/* ============================================================
    AD SLOT
============================================================ */
.ad-slot-wrap {
    position: relative; z-index: 1;
    margin: 0 5% 24px;
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 12px;
    min-height: 100px;
}
.ad-label { font-size: 0.7rem; color: var(--muted); text-align: center; margin-bottom: 6px; letter-spacing: 0.05em; text-transform: uppercase; }

/* ============================================================
    UNLOCK GATE
============================================================ */
.unlock-section {
    position: relative; z-index: 1;
    padding: 0 5% 60px;
}

.unlock-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 40px;
    max-width: 780px;
    margin: 0 auto;
}

/* Steps */
.unlock-steps { display: flex; align-items: center; gap: 0; margin-bottom: 32px; }
.unlock-step {
    display: flex; flex-direction: column; align-items: center; gap: 6px;
    flex: 1; text-align: center;
    font-size: 0.78rem; color: var(--muted); font-weight: 500;
    position: relative;
}
.unlock-step::after {
    content: ''; position: absolute; top: 16px; left: 60%;
    width: 80%; height: 1px; background: var(--border);
}
.unlock-step:last-child::after { display: none; }
.step-num {
    width: 34px; height: 34px; border-radius: 50%;
    display: flex; align-items: center; justify-content: center;
    background: var(--surface2); border: 1px solid var(--border);
    font-size: 0.82rem; font-weight: 700; color: var(--muted);
    transition: all 0.3s;
}
.unlock-step.done .step-num { background: var(--green-dim); border-color: var(--green); color: var(--green); }
.unlock-step.done span { color: var(--green); }
.unlock-step.active .step-num { background: rgba(96,165,250,0.15); border-color: var(--accent); color: var(--accent); animation: pulse-step 1.5s ease infinite; }
@keyframes pulse-step { 0%,100% { box-shadow: 0 0 0 0 rgba(96,165,250,0.3); } 50% { box-shadow: 0 0 0 8px rgba(96,165,250,0); } }

/* Instruction box */
.ad-instruction-box {
    background: var(--surface2);
    border: 1px solid rgba(163,230,53,0.2);
    border-radius: var(--radius);
    padding: 22px 24px;
    display: flex; align-items: flex-start; gap: 16px;
    margin-bottom: 24px;
    position: relative;
    overflow: hidden;
}
.ad-inst-pulse {
    position: absolute; top: 0; left: 0; right: 0; height: 2px;
    background: linear-gradient(90deg, transparent, var(--green), transparent);
    animation: shimmer 2.5s linear infinite;
}
@keyframes shimmer { 0% { transform: translateX(-100%); } 100% { transform: translateX(100%); } }
.ad-inst-text { flex: 1; }
.ad-inst-label { font-size: 0.72rem; font-weight: 700; color: var(--green); text-transform: uppercase; letter-spacing: 0.06em; display: block; margin-bottom: 6px; }
.ad-instruction-box h3 { font-family: 'Syne', sans-serif; font-size: 1.1rem; font-weight: 700; margin-bottom: 6px; }
.ad-instruction-box p { font-size: 0.88rem; color: var(--muted); }
.ad-instruction-box strong { color: var(--text); }
.ad-inst-arrow { display: flex; flex-direction: column; align-items: center; gap: 4px; flex-shrink: 0; color: var(--green); font-size: 0.72rem; font-weight: 700; }
.bounce-arrow { font-size: 1.6rem; animation: bounceY 1s ease infinite; }
@keyframes bounceY { 0%,100% { transform: translateY(0); } 50% { transform: translateY(6px); } }

/* Gate ad */
.gate-ad-wrap {
    background: var(--surface2);
    border: 2px dashed rgba(163,230,53,0.25);
    border-radius: var(--radius);
    padding: 20px;
    margin-bottom: 24px;
    transition: opacity 0.4s;
}
.gate-ad-label { font-size: 0.72rem; color: var(--green); text-align: center; font-weight: 600; margin-bottom: 10px; letter-spacing: 0.05em; text-transform: uppercase; }
.gate-ad-unit { min-height: 120px; }

/* Timer */
.unlock-timer { display: flex; align-items: center; gap: 18px; background: var(--surface2); border: 1px solid rgba(163,230,53,0.2); border-radius: var(--radius); padding: 18px 22px; }
.timer-ring { position: relative; width: 56px; height: 56px; flex-shrink: 0; }
.timer-ring svg { width: 100%; height: 100%; }
.timer-ring span { position: absolute; inset: 0; display: flex; align-items: center; justify-content: center; font-family: 'Syne', sans-serif; font-weight: 800; font-size: 1.1rem; color: var(--green); }
.unlock-timer p { font-size: 0.9rem; color: var(--muted); }
.unlock-timer strong { color: var(--text); }

.unlock-note { text-align: center; margin-top: 18px; font-size: 0.82rem; color: var(--muted); }
.unlock-already { background: none; border: none; color: var(--green); font-size: 0.82rem; cursor: pointer; font-weight: 600; text-decoration: underline; padding: 0; }

/* ============================================================
    NOTES SECTION (hidden until unlocked)
============================================================ */
.notes-section {
    position: relative; z-index: 1;
    padding: 0 5% 60px;
}

.notes-header {
    display: flex; align-items: flex-start; justify-content: space-between;
    flex-wrap: wrap; gap: 16px;
    margin-bottom: 28px;
}

.section-label {
    font-size: 0.72rem; font-weight: 700; color: var(--green);
    text-transform: uppercase; letter-spacing: 0.1em;
}

.section-title {
    font-family: 'Syne', sans-serif; font-size: 1.8rem; font-weight: 800;
    margin-top: 6px;
}

.notes-count-badge {
    padding: 6px 16px; border-radius: 20px;
    background: var(--green-dim); border: 1px solid rgba(163,230,53,0.2);
    font-size: 0.8rem; font-weight: 700; color: var(--green);
    align-self: center;
}

/* Notes grid — card style */
.notes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 18px;
    margin-bottom: 40px;
}

.note-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 22px;
    display: flex; flex-direction: column; gap: 14px;
    transition: border-color 0.25s, transform 0.2s;
    animation: fadeUp 0.5s ease both;
}
.note-card:hover { border-color: rgba(163,230,53,0.3); transform: translateY(-2px); }

@keyframes fadeUp { from { opacity:0; transform:translateY(20px); } to { opacity:1; transform:translateY(0); } }

.note-card-top { display: flex; align-items: center; justify-content: space-between; }

.note-icon-wrap {
    width: 42px; height: 42px; border-radius: 10px;
    display: flex; align-items: center; justify-content: center;
    font-size: 1.2rem;
}
.note-icon-wrap.green { background: var(--green-dim); }
.note-icon-wrap.blue  { background: rgba(96,165,250,0.12); }
.note-icon-wrap.yellow{ background: rgba(251,191,36,0.12); }

.note-type-tag {
    font-size: 0.7rem; font-weight: 700; padding: 3px 10px;
    border-radius: 20px; text-transform: uppercase; letter-spacing: 0.05em;
}
.note-type-tag.pdf  { background: rgba(163,230,53,0.12); color: var(--green); border: 1px solid rgba(163,230,53,0.2); }
.note-type-tag.zip  { background: rgba(96,165,250,0.12);  color: var(--accent); border: 1px solid rgba(96,165,250,0.2); }

.note-card h3 { font-family: 'Syne', sans-serif; font-size: 1rem; font-weight: 700; }
.note-card p  { font-size: 0.84rem; color: var(--muted); flex: 1; }

.note-dl-btn {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 9px 18px; border-radius: 9px;
    background: var(--green-dim); border: 1px solid rgba(163,230,53,0.25);
    color: var(--green); font-size: 0.84rem; font-weight: 700;
    transition: background 0.2s, border-color 0.2s;
    align-self: flex-start;
}
.note-dl-btn:hover { background: rgba(163,230,53,0.2); border-color: rgba(163,230,53,0.5); }

/* ============================================================
    VIDEO SECTION
============================================================ */
.video-section {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 32px;
    margin-bottom: 40px;
}
.video-section h3 {
    font-family: 'Syne', sans-serif; font-size: 1.2rem; font-weight: 700;
    margin-bottom: 6px;
}
.video-section p { font-size: 0.88rem; color: var(--muted); margin-bottom: 18px; }
.video-embed-wrap {
    position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden;
    border-radius: var(--radius); border: 1px solid var(--border);
}
.video-embed-wrap iframe { position: absolute; inset: 0; width: 100%; height: 100%; }

/* ============================================================
    CTA CARDS
============================================================ */
.pyq-banner {
    background: linear-gradient(135deg, rgba(163,230,53,0.06), rgba(96,165,250,0.06));
    border: 1px solid rgba(163,230,53,0.2);
    border-radius: var(--radius-lg);
    padding: 28px;
    margin-bottom: 18px;
}
.pyq-content { display: flex; align-items: center; gap: 20px; flex-wrap: wrap; }
.pyq-icon { font-size: 2.2rem; flex-shrink: 0; }
.pyq-text { flex: 1; min-width: 200px; }
.pyq-text h3 { font-family: 'Syne', sans-serif; font-size: 1.1rem; font-weight: 700; margin-bottom: 4px; }
.pyq-text p { font-size: 0.85rem; color: var(--muted); }

.notes-cta-card {
    background: var(--surface);
    border: 1px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 24px 28px;
    display: flex; align-items: center; gap: 18px; flex-wrap: wrap;
    margin-bottom: 40px;
}
.notes-cta-icon { font-size: 2rem; flex-shrink: 0; }
.notes-cta-text { flex: 1; min-width: 200px; }
.notes-cta-text h3 { font-family: 'Syne', sans-serif; font-size: 1rem; font-weight: 700; margin-bottom: 3px; }
.notes-cta-text p { font-size: 0.84rem; color: var(--muted); }

.btn {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 10px 22px; border-radius: 10px;
    font-size: 0.88rem; font-weight: 700; transition: all 0.2s;
    white-space: nowrap;
}
.btn-primary { background: var(--green); color: #0d0f18; }
.btn-primary:hover { background: #b5f542; }
.btn-outline { background: transparent; border: 1px solid var(--border); color: var(--text); }
.btn-outline:hover { border-color: rgba(163,230,53,0.4); color: var(--green); }

/* ============================================================
    FOOTER
============================================================ */
.footer {
    position: relative; z-index: 1;
    background: var(--surface);
    border-top: 1px solid var(--border);
    padding: 48px 5% 24px;
}
.footer-top { display: flex; gap: 48px; flex-wrap: wrap; margin-bottom: 32px; }
.footer-brand { flex: 2; min-width: 220px; }
.footer-brand .logo-text { font-family: 'Syne', sans-serif; font-size: 1.2rem; font-weight: 800; }
.footer-brand p { font-size: 0.84rem; color: var(--muted); margin: 10px 0 16px; }
.footer-yt {
    display: inline-flex; align-items: center; gap: 7px;
    padding: 8px 16px; border-radius: 8px;
    background: rgba(239,68,68,0.12); border: 1px solid rgba(239,68,68,0.25);
    color: #f87171; font-size: 0.84rem; font-weight: 600;
    transition: background 0.2s;
}
.footer-yt:hover { background: rgba(239,68,68,0.22); }
.footer-links-col { min-width: 140px; }
.footer-links-col h5 { font-family: 'Syne', sans-serif; font-size: 0.82rem; font-weight: 700; text-transform: uppercase; letter-spacing: 0.08em; color: var(--muted); margin-bottom: 14px; }
.footer-links-col a { display: block; font-size: 0.86rem; color: var(--muted); padding: 4px 0; transition: color 0.2s; }
.footer-links-col a:hover { color: var(--green); }
.footer-bottom { border-top: 1px solid var(--border); padding-top: 18px; font-size: 0.78rem; color: var(--muted); text-align: center; }
.footer-bottom a { color: var(--green); }