/* --- Global Variables & Reset (Pro Design) --- */
:root {
    --primary-color: #0066FF;       /* Modern Bright Blue */
    --primary-dark: #004ecc;
    --accent-color: #FF8C00;        /* Orange for CTA */
    --dark-bg: #0f172a;             /* Dark Slate */
    --light-bg: #f8fafc;            /* Very Light Blue-Grey */
    --text-dark: #1e293b;
    --text-light: #64748b;
    --white: #ffffff;
    --font-family: 'Hind Siliguri', sans-serif;
    --shadow-sm: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    --shadow-lg: 0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 10px 10px -5px rgba(0, 0, 0, 0.04);
    --radius: 16px;
}

* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html { scroll-behavior: smooth; }

body {
    font-family: var(--font-family);
    line-height: 1.7;
    background-color: var(--light-bg);
    color: var(--text-dark);
    overflow-x: hidden;
}

.container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

a { text-decoration: none; transition: 0.3s ease; }
ul { list-style: none; }
h1, h2, h3, h4 { font-weight: 700; line-height: 1.3; }

/* --- Header & Navigation (Glassmorphism) --- */
header {
    position: sticky;
    top: 0;
    z-index: 1000;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-bottom: 1px solid rgba(0,0,0,0.05);
    box-shadow: var(--shadow-sm);
}

nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    height: 80px;
}

.nav-links li a.btn-primary {
    color: var(--white) !important;
}

.logo img { height: 45px; width: auto; }

.nav-links { display: flex; align-items: center; gap: 30px; }

.nav-links li a {
    color: var(--text-dark);
    font-weight: 600;
    font-size: 1rem;
    position: relative;
}

.nav-links li a:not(.btn)::after {
    content: '';
    position: absolute;
    width: 0;
    height: 2px;
    bottom: -5px;
    left: 0;
    background-color: var(--primary-color);
    transition: width 0.3s;
}
.nav-links li a:not(.btn):hover::after { width: 100%; }

.hamburger { display: none; font-size: 1.5rem; cursor: pointer; color: var(--text-dark); }

/* --- Buttons --- */
.btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    padding: 12px 28px;
    border-radius: 50px;
    font-weight: 600;
    transition: all 0.3s ease;
    cursor: pointer;
    gap: 10px;
}

.btn-primary {
    background: linear-gradient(135deg, var(--primary-color), var(--primary-dark));
    color: var(--white);
    box-shadow: 0 10px 20px rgba(0, 102, 255, 0.2);
    border: none;
}

.btn-primary:hover {
    transform: translateY(-2px);
    box-shadow: 0 15px 30px rgba(0, 102, 255, 0.3);
}

.btn-large { padding: 16px 40px; font-size: 1.1rem; }

/* --- Hero Section (Modern Dark) --- */
#hero {
    position: relative;
    background: linear-gradient(135deg, rgba(15, 23, 42, 0.9) 0%, rgba(15, 23, 42, 0.8) 100%), 
                url('https://sohojaiinstitute.pixwhy.com/ai.jpeg');
    background-size: cover;
    background-position: center;
    background-attachment: fixed;
    height: 90vh;
    display: flex;
    align-items: center;
    text-align: center;
    color: var(--white);
}

.hero-content {
    max-width: 800px;
    margin: 0 auto;
    animation: fadeInUp 1s ease-out;
}

.hero-content h1 {
    font-size: 3.5rem;
    margin-bottom: 25px;
    background: linear-gradient(to right, #fff, #94a3b8);
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
}

.hero-content p {
    font-size: 1.25rem;
    color: #cbd5e1;
    margin-bottom: 40px;
}

/* --- Global Section Styles --- */
section { padding: 100px 0; }

.section-title {
    text-align: center;
    font-size: 2.5rem;
    margin-bottom: 60px;
    color: var(--text-dark);
    position: relative;
}

.section-title::after {
    content: '';
    display: block;
    width: 80px;
    height: 4px;
    background: var(--primary-color);
    margin: 15px auto 0;
    border-radius: 2px;
}

/* --- Features Section --- */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 30px;
}

.feature-card {
    background: var(--white);
    padding: 40px 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: all 0.3s ease;
    border: 1px solid rgba(0,0,0,0.03);
    text-align: center;
}

.feature-card:hover {
    transform: translateY(-10px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary-color);
}

.feature-card i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
    background: rgba(0, 102, 255, 0.1);
    width: 80px;
    height: 80px;
    line-height: 80px;
    border-radius: 50%;
    display: inline-block;
}

/* --- Video Examples Section --- */
#video-examples { background: #eef2ff; }
.video-types-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 30px;
}

.video-type-card {
    background: var(--white);
    padding: 30px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-sm);
    transition: transform 0.3s;
    position: relative;
    overflow: hidden;
}

.video-type-card:hover { transform: translateY(-5px); box-shadow: var(--shadow-lg); }

.video-type-card h3 {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 1.3rem;
    margin-bottom: 20px;
    color: var(--primary-color);
}

.video-type-card ul li {
    margin-bottom: 12px;
    padding-left: 25px;
    position: relative;
    color: var(--text-light);
}

.video-type-card ul li::before {
    content: '\f00c';
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    color: #10b981;
    position: absolute;
    left: 0;
    top: 2px;
}

/* --- Accordion (Modules & FAQ) --- */
.accordion { max-width: 900px; margin: 0 auto; }
.accordion-item {
    margin-bottom: 15px;
    background: var(--white);
    border-radius: 12px;
    box-shadow: var(--shadow-sm);
    overflow: hidden;
}

.accordion-header {
    width: 100%;
    padding: 20px 25px;
    background: var(--white);
    border: none;
    text-align: left;
    font-size: 1.1rem;
    font-weight: 600;
    font-family: var(--font-family);
    color: var(--text-dark);
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: background 0.3s;
}

.accordion-header:hover { background: #f1f5f9; }
.accordion-header::after {
    content: '\f078';
    font-family: 'Font Awesome 6 Free';
    font-weight: 900;
    transition: transform 0.3s;
    color: var(--primary-color);
}
.accordion-item.active .accordion-header::after { transform: rotate(180deg); }
.accordion-item.active .accordion-header { background: #f0f7ff; color: var(--primary-color); }

.accordion-content {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease-out;
    background: var(--white);
}

.accordion-content div { padding: 25px; border-top: 1px solid #f1f5f9; color: var(--text-light); }
.accordion-content p { margin-bottom: 10px; }
.accordion-content ol { padding-left: 20px; }
.accordion-content li { margin-bottom: 8px; }

/* --- Instructor Section --- */
.instructor-wrapper {
    display: flex;
    align-items: center;
    gap: 60px;
    background: var(--white);
    padding: 60px;
    border-radius: var(--radius);
    box-shadow: var(--shadow-lg);
}

.instructor-image img {
    width: 300px;
    height: 300px;
    object-fit: cover;
    border-radius: 20px;
    box-shadow: 20px 20px 0px rgba(0, 102, 255, 0.1);
}

.instructor-bio h3 { font-size: 1.8rem; margin: 10px 0 20px; color: var(--primary-color); }
.instructor-bio p { color: var(--text-light); font-size: 1.1rem; }

/* --- Testimonials --- */
#testimonials { background: var(--dark-bg); color: var(--white); }
#testimonials .section-title { color: var(--white); }
#testimonials .section-title::after { background: var(--accent-color); }

.testimonial-card {
    background: rgba(255, 255, 255, 0.05);
    padding: 40px;
    border-radius: var(--radius);
    backdrop-filter: blur(5px);
    border: 1px solid rgba(255, 255, 255, 0.1);
}

.testimonials-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 30px;
}

.testimonial-card p { font-style: italic; font-size: 1.1rem; margin-bottom: 20px; color: #cbd5e1; }
.testimonial-card h4 { color: var(--accent-color); font-weight: 600; }

/* --- Pricing Section --- */
.pricing-card {
    max-width: 500px;
    margin: 0 auto;
    background: var(--white);
    padding: 60px 40px;
    border-radius: 24px;
    text-align: center;
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.25);
    position: relative;
    border: 2px solid var(--primary-color);
    overflow: hidden;
}

.pricing-badge {
    position: absolute;
    top: 20px;
    right: -35px;
    background: var(--accent-color);
    color: #fff;
    padding: 5px 40px;
    transform: rotate(45deg);
    font-size: 0.9rem;
    font-weight: 700;
}

.price-container { margin: 30px 0; }
.original-price { font-size: 1.5rem; text-decoration: line-through; color: #94a3b8; }
.current-price { font-size: 4rem; font-weight: 700; color: var(--text-dark); line-height: 1; }
.discount-badge { 
    background: #dcfce7; color: #166534; 
    padding: 5px 15px; border-radius: 20px; 
    font-weight: 600; font-size: 0.9rem; vertical-align: middle;
}

.pricing-card ul { text-align: left; margin: 30px 0; padding-left: 10px; }
.pricing-card li { margin-bottom: 15px; font-size: 1.1rem; color: var(--text-light); }
.pricing-card li i { color: #10b981; margin-right: 10px; }

/* Button Pulse Animation */
.pricing-card .btn { width: 100%; animation: pulse 2s infinite; }
@keyframes pulse {
    0% { box-shadow: 0 0 0 0 rgba(0, 102, 255, 0.7); }
    70% { box-shadow: 0 0 0 10px rgba(0, 102, 255, 0); }
    100% { box-shadow: 0 0 0 0 rgba(0, 102, 255, 0); }
}

/* --- Footer --- */
footer { background: #0f172a; color: #94a3b8; padding: 80px 0 30px; margin-top: 0; }
.footer-main { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 50px; margin-bottom: 50px; }

.footer-column h4 { color: var(--white); font-size: 1.2rem; margin-bottom: 25px; }
.footer-column ul li { margin-bottom: 12px; }
.footer-column a { color: #94a3b8; transition: 0.3s; }
.footer-column a:hover { color: var(--primary-color); padding-left: 5px; }

.footer-social-icons a { font-size: 1.5rem; margin-right: 15px; color: #94a3b8; }
.footer-social-icons a:hover { color: var(--white); }
.footer-bottom { border-top: 1px solid #1e293b; padding-top: 30px; text-align: center; font-size: 0.9rem; }

/* --- Popup Modal --- */
.popup-overlay {
    position: fixed; top: 0; left: 0; width: 100%; height: 100%;
    background: rgba(0,0,0,0.8); backdrop-filter: blur(5px);
    display: none; justify-content: center; align-items: center; z-index: 2000;
}
.popup-content {
    background: var(--white); padding: 50px; border-radius: 20px;
    text-align: center; max-width: 450px; width: 90%; position: relative;
    box-shadow: 0 25px 50px -12px rgba(0,0,0,0.25);
    animation: fadeInUp 0.4s ease-out;
}
.popup-close {
    position: absolute; top: 15px; right: 20px;
    font-size: 30px; cursor: pointer; color: #94a3b8;
}

@keyframes fadeInUp {
    from { opacity: 0; transform: translateY(30px); }
    to { opacity: 1; transform: translateY(0); }
}

/* ========================================= */
/* INNER PAGES (Login, Course, etc)     */
/* ========================================= */

/* --- Login Page (start-course.html) --- */
.login-page-wrapper {
    display: flex;
    justify-content: center;
    align-items: center;
    min-height: calc(100vh - 130px);
    background: linear-gradient(45deg, #f0f2f5, #e6e9ee);
    padding: 40px 20px;
}
.login-card {
    max-width: 450px;
    width: 100%;
    background: #fff;
    padding: 40px;
    border-radius: 12px;
    box-shadow: 0 15px 40px rgba(0,0,0,0.1);
    text-align: center;
}
.login-card .logo-icon { font-size: 3rem; color: var(--primary-color); margin-bottom: 20px; }
.login-card h2 { margin-bottom: 15px; color: var(--dark-bg); }
.login-card p { color: #666; margin-bottom: 30px; }
.login-card input {
    width: 100%; padding: 14px; margin-bottom: 20px;
    border: 1px solid #ddd; border-radius: 8px; font-size: 1rem; text-align: center;
}
.login-card .error-message { color: #dc3545; margin-bottom: 15px; font-weight: 500; display: none; }

/* --- About & Courses Page General --- */
.page-header { background-color: var(--light-bg); padding: 60px 0; text-align: center; }
.page-header h1 { font-size: 2.8rem; color: var(--dark-bg); }

/* About Page */
.about-section { padding: 80px 0; }
.about-content { display: flex; gap: 50px; align-items: center; }
.about-content .text-content { flex: 1; }
.about-content .image-content { flex: 1; text-align: center; }
.about-content img { max-width: 100%; border-radius: 20px; box-shadow: var(--shadow-lg); }
.mission-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(250px, 1fr)); gap: 30px; margin-top: 50px; }

/* Courses Page */
.courses-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(320px, 1fr)); gap: 30px; padding: 80px 0; }
.course-card {
    background: var(--white); border-radius: var(--radius);
    box-shadow: var(--shadow-sm); overflow: hidden;
    display: flex; flex-direction: column; transition: 0.3s;
}
.course-card:hover { transform: translateY(-8px); box-shadow: var(--shadow-lg); }
.course-card img { width: 100%; height: 200px; object-fit: cover; }
.course-card-content { padding: 25px; flex-grow: 1; display: flex; flex-direction: column; }
.course-card-content h3 { margin-bottom: 10px; font-size: 1.4rem; }
.course-card-content p { flex-grow: 1; margin-bottom: 20px; color: var(--text-light); }
.course-card-content .btn { align-self: flex-start; }

/* --- Course Player Page (ai-next-level.html) --- */
.course-page-header {
    background: var(--white); padding: 30px; border-radius: 12px;
    margin-bottom: 30px; box-shadow: var(--shadow-sm);
}
.course-page-header h1 { font-size: 2rem; margin-bottom: 15px; }
.progress-bar-container { background: #e9ecef; border-radius: 20px; height: 12px; width: 100%; }
.progress-bar {
    background: linear-gradient(90deg, #10b981, #059669);
    height: 100%; width: 0%; border-radius: 20px; transition: width 0.5s ease-in-out;
}
.progress-text { text-align: right; font-weight: 600; margin-top: 8px; color: var(--text-dark); }

.course-layout { display: grid; grid-template-columns: 1fr 350px; gap: 30px; }
.course-main-content {
    background: var(--white); border-radius: 12px;
    box-shadow: var(--shadow-sm); overflow: hidden;
}
.youtube-embed-container { position: relative; padding-bottom: 56.25%; height: 0; overflow: hidden; }
.youtube-embed-container iframe { position: absolute; top: 0; left: 0; width: 100%; height: 100%; }
.video-content-area { padding: 25px; }

.course-sidebar {
    background: var(--white); border-radius: 12px; padding: 25px;
    height: fit-content; position: sticky; top: 100px; box-shadow: var(--shadow-sm);
}
#sidebar-lesson-list-container { max-height: calc(100vh - 220px); overflow-y: auto; padding-right: 10px; }
.sidebar-module h4 {
    font-size: 1.1rem; padding-bottom: 10px; margin-bottom: 10px;
    border-bottom: 2px solid #eee; color: var(--primary-color);
}
.sidebar-lesson { margin-bottom: 5px; }
.sidebar-lesson a {
    display: flex; align-items: center; padding: 12px; border-radius: 6px;
    color: var(--text-dark); font-weight: 500; transition: 0.3s;
}
.sidebar-lesson a:hover { background-color: #f1f3f5; }
.sidebar-lesson a.active { background-color: var(--primary-color); color: var(--white); }
.sidebar-lesson-icon { margin-right: 12px; width: 20px; text-align: center; }
.sidebar-lesson.completed a { color: #94a3b8; text-decoration: line-through; }
.sidebar-lesson.completed .fa-circle-play { display: none; }
.sidebar-lesson .fa-check-circle { display: none; color: #10b981; }
.sidebar-lesson.completed .fa-check-circle { display: inline-block; }

/* --- Responsive --- */
@media (max-width: 992px) {
    .course-layout { grid-template-columns: 1fr; }
    .course-sidebar { position: static; margin-top: 30px; }
}

@media (max-width: 768px) {
    .hero-content h1 { font-size: 2.2rem; }
    .instructor-wrapper { flex-direction: column; text-align: center; padding: 30px; }
    .instructor-image img { width: 200px; height: 200px; box-shadow: none; margin-bottom: 20px; }
    
    .nav-links {
        position: fixed; top: 80px; left: -100%; width: 100%; height: calc(100vh - 80px);
        background: var(--white); flex-direction: column; padding-top: 50px; transition: 0.3s;
        box-shadow: 0 10px 10px rgba(0,0,0,0.1);
    }
    .nav-links.active { left: 0; }
    .hamburger { display: block; }
    .nav-cta { width: 80%; text-align: center; }
    .nav-cta a { width: 100%; display: block; }
    
    .about-content { flex-direction: column; }
    .testimonials-grid { grid-template-columns: 1fr; }
}
/* --- Locked Lesson List Design --- */
.accordion-content {
    padding: 0 !important; /* আগের প্যাডিং রিসেট */
}

.locked-lesson-list {
    list-style: none;
    padding: 0;
    margin: 0;
}

.locked-lesson-list li {
    display: flex;
    justify-content: space-between; /* লেখা বামে, তালা ডানে */
    align-items: center;
    padding: 15px 20px;
    border-bottom: 1px solid #f0f0f0;
    color: #666; /* একটু হালকা কালার (Disabled ভাব আনার জন্য) */
    font-size: 0.95rem;
    transition: all 0.3s ease;
    background-color: #fff;
    cursor: not-allowed; /* মাউস নিলে দেখাবে ক্লিক করা যাবে না */
}

.locked-lesson-list li:hover {
    background-color: #f9fafb; /* হোভার করলে হালকা পরিবর্তন */
    color: #444;
}

.locked-lesson-list li:last-child {
    border-bottom: none;
}

/* বাম পাশের প্লে আইকন */
.lesson-text i {
    margin-right: 10px;
    color: #94a3b8; /* আইকনের কালার হালকা */
    font-size: 1rem;
}

/* ডান পাশের লক আইকন */
.status-icon {
    background: #f1f5f9;
    width: 30px;
    height: 30px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 50%;
    color: #ef4444; /* লালচে রঙ (Lock বোঝাতে) অথবা #999 দিতে পারেন */
    font-size: 0.8rem;
}

/* মোবাইল ভিউতে টেক্সট যাতে ভেঙে না যায় */
@media (max-width: 480px) {
    .locked-lesson-list li {
        font-size: 0.85rem;
        padding: 12px 15px;
    }
}

/* --- AI Tools Carousel Fixed (Updated Logic) --- */
.tools-section {
    background-color: var(--white);
    padding: 60px 0;
    overflow: hidden;
}

.slider {
    height: 100px;
    margin: auto;
    overflow: hidden;
    position: relative;
    width: 100%;
}

/* দুই পাশের সাদা ফেড এফেক্ট */
.slider::before,
.slider::after {
    background: linear-gradient(to right, rgba(255,255,255,1) 0%, rgba(255,255,255,0) 100%);
    content: "";
    height: 100px;
    position: absolute;
    width: 100px;
    z-index: 2;
}
.slider::after { right: 0; top: 0; transform: rotateZ(180deg); }
.slider::before { left: 0; top: 0; }

/* ⚠️ সবচেয়ে গুরুত্বপূর্ণ অংশ: Track Width Fixed */
.slide-track {
    display: flex;
    /* আমরা ধরে নিচ্ছি ২০টি লোগো থাকবে (১০টি আসল + ১০টি ডুপ্লিকেট) */
    width: calc(200px * 20); 
    animation: scroll 40s linear infinite;
}

.slide {
    height: 100px;
    width: 200px; /* প্রতিটি লোগোর জন্য বরাদ্দ জায়গা */
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 0 25px; /* দুই লোগোর মাঝখানের গ্যাপ */
}

.slide img {
    max-width: 100%; 
    max-height: 60px; /* সব লোগোর উচ্চতা সমান থাকবে */
    width: auto;
    object-fit: contain; /* লোগো চ্যাপ্টা হবে না */
    filter: grayscale(100%);
    opacity: 0.6;
    transition: all 0.3s ease;
    cursor: pointer;
}

.slide img:hover {
    filter: grayscale(0%);
    opacity: 1;
    transform: scale(1.1);
}

@keyframes scroll {
    0% { transform: translateX(0); }
    /* এখানে -200px * (আসল লোগো সংখ্যা ১০) = -2000px */
    100% { transform: translateX(calc(-200px * 10)); } 
}

/* --- Google Doc Responsive Embed (Fixed Height) --- */
.google-doc-wrapper {
    position: relative;
    width: 100%;
    height: 800px; /* পিসিতে ৮০০ পিক্সেল লম্বা */
    border: 1px solid #ddd;
    border-radius: 8px;
    overflow: hidden;
    margin-top: 15px;
    background: #fff;
}

.google-doc-wrapper iframe {
    position: absolute;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    border: none;
}

/* মোবাইলের জন্য হাইট অ্যাডজাস্টমেন্ট */
@media (max-width: 768px) {
    .google-doc-wrapper {
        height: 500px; /* মোবাইলে ৫০০ পিক্সেল লম্বা */
    }
}