@import url('https://fonts.googleapis.com/css2?family=Lexend:wght@300;400;500;600;700&family=Public+Sans:wght@300;400;500;600;700;800&display=swap');

:root {
    /* Design System Variables */
    --primary-container: #003366;
    --secondary-container: #FDB913;
    --on-surface: #1b1b1b;
    --on-surface-variant: #43474f;
    --surface-container: #eeeeee;

    /* BIT Institutional Theme (Dark Mode Default) */
    --bg-dark: #0f172a;
    --bg-secondary: #1ac87a;
    --nav-bg: rgba(15, 17, 42, 0.85);
    --primary-blue: #1e40af;
    --accent-blue: #3b82f6;
    --primary-teal-light: rgba(59, 130, 246, 0.1);
    --text-white: #ffffff;
    --text-primary: #f8fafc;
    --text-gray: #94a3b8;
    --border-color: rgba(255, 255, 255, 0.1);
    --card-bg: rgba(30, 41, 59, 0.7);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

[data-theme="light"] {
    --bg-dark: #f9f9f9;
    --bg-secondary: #ffffff;
    --nav-bg: rgba(255, 255, 255, 0.95);
    --text-white: #0f172a;
    --text-primary: #1e293b;
    --text-gray: #64748b;
    --border-color: rgba(0, 0, 0, 0.08);
    --card-bg: #ffffff;
    --accent-blue: var(--primary-container);
}

.text-teal {
    color: var(--accent-blue) !important;
}

.bg-teal-light {
    background-color: var(--primary-teal-light) !important;
}

body {
    background-color: var(--bg-dark);
    color: var(--text-primary);
    font-family: 'Lexend', sans-serif;
    overflow-x: hidden;
    transition: background-color 0.3s, color 0.3s;
}

.content-wrapper {
    padding-top: 80px;
}

@media (min-width: 992px) {
    .content-wrapper {
        padding-top: 100px;
    }
}

/* Header & Navigation */
.navbar {
    background-color: var(--nav-bg) !important;
    backdrop-filter: blur(20px);
    -webkit-backdrop-filter: blur(20px);
    border-bottom: 1px solid var(--border-color);
    padding: 0.75rem 0;
    transition: var(--transition);
}

.brand-logo {
    height: 35px;
    width: auto;
}

.brand-title {
    font-family: 'Public Sans', sans-serif;
    font-weight: 700;
    font-size: 1.1rem;
    line-height: 1.2;
    color: var(--text-primary);
}

.brand-subtitle {
    font-size: 0.7rem;
    color: var(--text-gray);
    font-weight: 400;
}

@media (min-width: 992px) {
    .navbar {
        padding: 1rem 0;
    }

    .brand-logo {
        height: 45px;
    }

    .brand-title {
        font-size: 1.3rem;
    }
}

.nav-link {
    color: var(--text-gray) !important;
    font-weight: 500;
    font-size: 1rem;
    padding: 0.75rem 0 !important;
    transition: var(--transition);
}

@media (min-width: 992px) {
    .nav-link {
        font-size: 0.95rem;
        padding: 0.5rem 1rem !important;
        margin: 0 5px;
    }
}

.nav-link:hover,
.nav-link.active {
    color: var(--accent-blue) !important;
}

/* Theme Toggle */
.theme-toggle {
    cursor: pointer;
    width: 38px;
    height: 38px;
    display: flex;
    align-items: center;
    justify-content: center;
    border-radius: 10px;
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-gray);
    transition: var(--transition);
}

.theme-toggle:hover {
    color: var(--accent-blue);
    border-color: var(--accent-blue);
    transform: translateY(-2px);
}

/* Buttons */
.btn-login,
.btn-register {
    padding: 8px 18px;
    border-radius: 8px;
    font-weight: 600;
    text-align: center;
    transition: var(--transition);
    font-size: 0.9rem;
}

.btn-login {
    color: var(--accent-blue) !important;
    border: 1px solid var(--border-color);
    background: transparent;
}

.btn-register {
    background: var(--secondary-container);
    color: #1b1b1b !important;
    border: 1px solid transparent;
}

@media (min-width: 992px) {

    .btn-login,
    .btn-register {
        padding: 8px 25px;
    }
}

.btn-login:hover {
    border-color: var(--accent-blue);
    background: var(--primary-teal-light);
}

.btn-register:hover {
    background-color: #e5a800;
    transform: translateY(-8px);
    box-shadow: 0 8px 24px rgba(253, 185, 19, 0.4);
}

/* Header Search */
.header-search {
    width: 100%;
}

@media (min-width: 992px) {
    .header-search {
        width: 250px;
    }
}

.header-search .input-group {
    background: var(--bg-secondary);
    border-radius: 10px;
    border: 1px solid var(--border-color);
    overflow: hidden;
    transition: var(--transition);
}

.header-search .input-group:focus-within {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px var(--primary-teal-light);
}

.header-search .form-control {
    background: transparent;
    border: none;
    color: var(--text-primary);
    padding: 0.6rem 0.75rem;
    font-size: 0.9rem;
}

.header-search .form-control::placeholder {
    color: var(--text-gray);
    opacity: 0.6;
}

.header-search .form-control:focus {
    box-shadow: none;
}

/* Hero Section */
.hero-section {
    padding: 100px 0;
    position: relative;
    min-height: calc(100vh - 80px);
    display: flex;
    align-items: center;
}

.hero-title {
    font-size: 4.5rem;
    font-weight: 800;
    line-height: 1.1;
    margin-bottom: 25px;
}

.hero-subtitle {
    font-size: 1.25rem;
    color: var(--text-gray);
    margin-bottom: 40px;
    max-width: 550px;
    line-height: 1.6;
}

/* Book Cards Section */
.books-section {
    padding: 80px 0;
}

.section-title {
    font-size: 2.5rem;
    font-weight: 800;
    margin-bottom: 40px;
    text-align: center;
}

/* Book Card Aesthetics */
.book-card {
    background: var(--card-bg);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    transition: var(--transition);
    position: relative;
    backdrop-filter: blur(10px);
}

.book-card:hover {
    border-color: var(--accent-blue);
    box-shadow: 0 25px 50px -12px rgba(0, 0, 0, 0.5);
    transform: translateY(-5px);
}

.book-title {
    font-family: 'Inter', sans-serif;
    font-weight: 600;
    font-size: 1rem;
    line-height: 1.4;
}

/* Admin Styles */
.admin-wrapper {
    display: flex;
    min-height: 100vh;
}

.sidebar {
    width: 250px;
    background-color: var(--bg-secondary);
    border-right: 1px solid var(--border-color);
    padding: 20px 0;
    position: fixed;
    height: 100vh;
    overflow-y: auto;
    z-index: 1000;
}

.main-content {
    margin-left: 250px;
    flex: 1;
    padding: 40px;
}

.nav-link-admin {
    display: flex;
    align-items: center;
    padding: 12px 25px;
    color: var(--text-gray);
    text-decoration: none;
    transition: var(--transition);
    border-left: 3px solid transparent;
}

.nav-link-admin i {
    width: 20px;
    margin-right: 15px;
}

.nav-link-admin:hover,
.nav-link-admin.active {
    color: var(--accent-blue);
    background: var(--primary-teal-light);
    border-left-color: var(--accent-blue);
}

.admin-header {
    background-color: var(--nav-bg);
    backdrop-filter: blur(10px);
    padding: 15px 30px;
    border-bottom: 1px solid var(--border-color);
    display: flex;
    justify-content: space-between;
    align-items: center;
    position: sticky;
    top: 0;
    z-index: 999;
}

.card-admin {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 15px;
    padding: 25px;
    transition: var(--transition);
}

.table-dark-custom {
    background: transparent !important;
}

.table-dark-custom th {
    background: var(--primary-teal-light);
    color: var(--text-gray);
    font-weight: 500;
    border-bottom: 1px solid var(--border-color);
}

.table-dark-custom td {
    color: var(--text-primary);
    border-bottom: 1px solid var(--border-color);
    vertical-align: middle;
}

/* Footer */
footer {
    background-color: var(--bg-secondary);
    padding: 80px 0 30px;
    border-top: 1px solid var(--border-color);
}

footer a {
    color: var(--text-gray);
}

footer a:hover {
    color: var(--accent-blue);
}

/* Background Icons */
.bg-icon {
    position: absolute;
    opacity: 0.03;
    color: var(--text-primary);
    z-index: 1;
}

/* Category Cards */
.category-card {
    display: block;
    transition: var(--transition);
}

.category-card:hover {
    transform: translateY(-10px);
}

.category-card .card {
    border: 1px solid var(--border-color) !important;
    transition: var(--transition);
}

.category-card:hover .card {
    border-color: var(--accent-blue) !important;
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.4);
}

.category-card img {
    transition: transform 0.5s ease;
}

.category-card:hover img {
    transform: scale(1.1);
    opacity: 0.9 !important;
}

/* Responsive Headings */
@media (max-width: 991px) {
    .hero-title {
        font-size: 3.5rem;
    }
}

@media (max-width: 767px) {
    .hero-title {
        font-size: 2.8rem;
    }
}


/* --- MOBILE REFACOR & PREMIUM FEATURES --- */

/* Mobile Bottom Navigation */
.mobile-bottom-nav {
    position: fixed;
    bottom: 0;
    left: 0;
    width: 100%;
    background: var(--nav-bg);
    backdrop-filter: blur(25px);
    -webkit-backdrop-filter: blur(25px);
    border-top: 1px solid var(--border-color);
    padding: 10px 0 15px;
    z-index: 1040;
    box-shadow: 0 -10px 40px rgba(0, 0, 0, 0.3);
}

.mobile-bottom-nav .nav-item {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    text-decoration: none;
    color: var(--text-gray);
    font-size: 0.7rem;
    font-weight: 500;
    letter-spacing: 0.5px;
    transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    opacity: 0.7;
    position: relative;
    padding: 5px 15px;
}

.mobile-bottom-nav .nav-item i {
    font-size: 1.35rem;
    margin-bottom: 5px;
    transition: transform 0.3s ease;
}

.mobile-bottom-nav .nav-item:hover,
.mobile-bottom-nav .nav-item.active {
    color: var(--accent-blue);
    opacity: 1;
}

.mobile-bottom-nav .nav-item.active i {
    transform: translateY(-3px);
    filter: drop-shadow(0 4px 6px rgba(59, 130, 246, 0.5));
}

.mobile-bottom-nav .nav-item.active::after {
    content: '';
    position: absolute;
    bottom: -5px;
    width: 20px;
    height: 3px;
    background: var(--accent-blue);
    border-radius: 10px;
    box-shadow: 0 0 10px var(--accent-blue);
}

/* User Avatar */
.user-avatar-sm {
    width: 35px;
    height: 35px;
    background: linear-gradient(135deg, var(--primary-blue), var(--accent-blue));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 0.9rem;
    box-shadow: 0 2px 10px rgba(59, 130, 246, 0.3);
}

/* User Dropdown Button */
.user-dropdown-btn {
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.user-dropdown-btn:hover,
.user-dropdown-btn[aria-expanded="true"] {
    background: rgba(255, 255, 255, 0.08);
    border-color: var(--accent-blue);
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.2);
    color: var(--text-white);
}

/* Dropdown Menu Refinements */
.dropdown-menu-dark {
    background-color: var(--bg-secondary);
    border: 1px solid var(--border-color);
    box-shadow: 0 20px 50px rgba(0, 0, 0, 0.5) !important;
}

.dropdown-item {
    color: var(--text-gray);
    transition: var(--transition);
}

.dropdown-item:hover {
    background-color: var(--primary-teal-light);
    color: var(--text-white);
    transform: translateX(5px);
}

/* Mobile Search Overlay/Expand */
#mobile-search-bar input {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    color: var(--text-white);
    backdrop-filter: blur(10px);
}

#mobile-search-bar input::placeholder {
    color: var(--text-gray);
}

#mobile-search-bar input:focus {
    border-color: var(--accent-blue);
    box-shadow: 0 0 0 3px var(--primary-teal-light);
}

/* Spacer for mobile */
@media (max-width: 991px) {
    .content-wrapper {
        padding-bottom: 90px;
        /* Space for bottom nav */
    }
}

/* --- STATS COUNTER SECTION --- */
.stats-section {
    position: relative;
    padding: 80px 0;
    background: linear-gradient(rgba(15, 23, 42, 0.9), rgba(15, 23, 42, 0.9)), url('../assets/images/campus-bg.jpg');
    /* user might not have this bg, but fallback is color */
    background-size: cover;
    background-attachment: fixed;
    text-align: center;
    color: white;
}

.counter-box {
    padding: 40px 20px;
    border-right: 1px solid rgba(255, 255, 255, 0.1);
}

.counter-box:last-child {
    border-right: none;
}

.counter-number {
    font-size: 3.5rem;
    font-weight: 800;
    color: var(--accent-blue);
    margin-bottom: 10px;
    display: block;
}

.counter-text {
    font-size: 1.1rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 1px;
    color: var(--text-gray);
}

@media (max-width: 768px) {
    .counter-box {
        border-right: none;
        border-bottom: 1px solid rgba(255, 255, 255, 0.1);
    }
}

/* --- COURSE / ACADEMICS SECTION --- */
.course-card {
    background: var(--bg-secondary);
    border: 1px solid var(--border-color);
    border-radius: 12px;
    overflow: hidden;
    transition: var(--transition);
    height: 100%;
}

.course-card:hover {
    transform: translateY(-5px);
    border-color: var(--accent-blue);
    box-shadow: 0 20px 40px rgba(0, 0, 0, 0.2);
}

.course-img-wrapper {
    height: 200px;
    overflow: hidden;
    position: relative;
}

.course-img {
    width: 100%;
    height: 100%;
    object-fit: cover;
    transition: transform 0.5s ease;
}

.course-card:hover .course-img {
    transform: scale(1.1);
}

.course-content {
    padding: 25px;
}

.course-title {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 10px;
    color: var(--text-primary);
}

.course-desc {
    font-size: 0.9rem;
    color: var(--text-gray);
    margin-bottom: 20px;
}

/* --- TESTIMONIALS / ACHIEVERS --- */
.testimonial-section {
    padding: 100px 0;
    background: var(--bg-dark);
}

.testimonial-card {
    background: var(--card-bg);
    padding: 40px;
    border-radius: 20px;
    text-align: center;
    position: relative;
    border: 1px solid var(--border-color);
    transition: var(--transition);
}

.testimonial-card:hover {
    border-color: var(--accent-blue);
    transform: translateY(-5px);
}

.quote-icon {
    font-size: 2rem;
    color: var(--accent-blue);
    margin-bottom: 20px;
    opacity: 0.5;
}

.student-img {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    margin-bottom: 20px;
    border: 3px solid var(--accent-blue);
    padding: 3px;
    object-fit: cover;
}

.student-name {
    font-weight: 700;
    color: var(--text-primary);
    margin-bottom: 5px;
}

.student-course {
    color: var(--accent-blue);
    font-size: 0.85rem;
    font-weight: 600;
    margin-bottom: 20px;
    display: block;
}

.student-quote {
    color: var(--text-gray);
    font-style: italic;
    font-size: 0.95rem;
    line-height: 1.6;
}

/* --- MULTI-STEP REGISTRATION --- */
.registration-step {
    display: none;
}
.registration-step.active {
    display: block;
    animation: fadeIn 0.5s ease;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(10px); }
    to { opacity: 1; transform: translateY(0); }
}

.progress-stepper {
    display: flex;
    justify-content: space-between;
    margin-bottom: 3rem;
    position: relative;
    max-width: 500px;
    margin-left: auto;
    margin-right: auto;
}

.progress-stepper::before {
    content: '';
    position: absolute;
    top: 50%;
    left: 0;
    right: 0;
    height: 2px;
    background: var(--border-color);
    z-index: 1;
    transform: translateY(-50%);
}

.step-item {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 2;
    font-weight: 700;
    color: var(--text-gray);
    transition: var(--transition);
}

.step-item.active {
    background: var(--accent-blue);
    border-color: var(--accent-blue);
    color: white;
    box-shadow: 0 0 15px rgba(59, 130, 246, 0.5);
}

.step-item.completed {
    background: #10b981;
    border-color: #10b981;
    color: white;
}

.upload-box {
    border: 2px dashed var(--border-color);
    border-radius: 15px;
    padding: 2rem;
    text-align: center;
    cursor: pointer;
    transition: var(--transition);
}

.upload-box:hover {
    border-color: var(--accent-blue);
    background: var(--primary-teal-light);
}