/* ============================================
   THINKPHARMA - MAIN STYLESHEET
   ============================================ */

/* ---------- CSS Variables ---------- */
:root {
    --primary-color: #0b3d91;
    --primary-dark: #082a66;
    --secondary-color: #00b4d8;
    --accent-color: #90e0ef;
    --text-dark: #1a1a2e;
    --text-light: #666;
    --white: #ffffff;
    --bg-light: #f5f7fa;
    --bg-gradient: linear-gradient(135deg, #0b3d91 0%, #00b4d8 100%);
    --shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
    --shadow-hover: 0 8px 25px rgba(0, 0, 0, 0.15);
    --border-radius: 12px;
    --transition: all 0.3s ease;
}

/* ---------- Reset & Base Styles ---------- */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

html {
    scroll-behavior: smooth;
}

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.6;
}

a {
    text-decoration: none;
    color: inherit;
}

ul {
    list-style: none;
}

/* ============================================
   NAVIGATION BAR
   ============================================ */
.navbar {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 5%;
    background: var(--white);
    box-shadow: var(--shadow);
    position: sticky;
    top: 0;
    z-index: 1000;
}

.nav-brand {
    font-size: 1.8rem;
    font-weight: bold;
    color: var(--primary-color);
}

.nav-brand i {
    margin-right: 8px;
}

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

.nav-links a {
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-dark);
    padding: 8px 15px;
    border-radius: 25px;
    transition: var(--transition);
}

.nav-links a:hover,
.nav-links a.active {
    background: var(--primary-color);
    color: var(--white);
}

/* Hamburger Menu (Mobile) */
.hamburger {
    display: none;
    flex-direction: column;
    cursor: pointer;
    gap: 5px;
}

.hamburger span {
    width: 25px;
    height: 3px;
    background: var(--primary-color);
    border-radius: 5px;
    transition: var(--transition);
}

/* ============================================
   HERO SECTION
   ============================================ */
.hero {
    background: var(--bg-gradient);
    color: var(--white);
    text-align: center;
    padding: 80px 20px;
    min-height: 60vh;
    display: flex;
    align-items: center;
    justify-content: center;
}

.hero-content h1 {
    font-size: 3rem;
    margin-bottom: 15px;
    text-shadow: 2px 2px 4px rgba(0, 0, 0, 0.2);
}

.hero-content p {
    font-size: 1.3rem;
    margin-bottom: 10px;
    opacity: 0.9;
}

.hero-content h3 {
    font-size: 1.1rem;
    font-weight: 400;
    margin-bottom: 30px;
    opacity: 0.85;
}

.btn-primary {
    display: inline-block;
    padding: 15px 40px;
    background: var(--white);
    color: var(--primary-color);
    font-size: 1.1rem;
    font-weight: 600;
    border-radius: 50px;
    transition: var(--transition);
    box-shadow: var(--shadow);
}

.btn-primary:hover {
    background: var(--accent-color);
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

/* ============================================
   SECTIONS (Common Styles)
   ============================================ */
section {
    padding: 60px 5%;
}

section h2 {
    text-align: center;
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 40px;
}

/* ============================================
   GRID LAYOUT
   ============================================ */
.grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
    gap: 25px;
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 20px;
}

/* ============================================
   SEMESTER CARDS
   ============================================ */
.semesters {
    background: var(--white);
}

.card {
    background: var(--bg-light);
    padding: 30px 20px;
    text-align: center;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
}

.card:hover {
    background: var(--primary-color);
    color: var(--white);
    transform: translateY(-8px);
    box-shadow: var(--shadow-hover);
    border-color: var(--secondary-color);
}

.card i {
    font-size: 2.5rem;
    margin-bottom: 15px;
    color: var(--secondary-color);
}

.card:hover i {
    color: var(--white);
}

.card h3 {
    font-size: 1.2rem;
    margin-bottom: 8px;
}

.card p {
    font-size: 0.9rem;
    opacity: 0.8;
}

/* ============================================
   FEATURE CARDS
   ============================================ */
.features {
    background: var(--bg-light);
}

.feature-card {
    background: var(--white);
    padding: 40px 25px;
    text-align: center;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    transition: var(--transition);
}

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

.feature-card i {
    font-size: 3rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.feature-card h3 {
    font-size: 1.3rem;
    margin-bottom: 10px;
    color: var(--text-dark);
}

.feature-card p {
    color: var(--text-light);
    font-size: 0.95rem;
}

/* ============================================
   FOOTER
   ============================================ */
footer {
    background: var(--primary-dark);
    color: var(--white);
    text-align: center;
    padding: 40px 20px;
}

.footer-content h3 {
    font-size: 1.8rem;
    margin-bottom: 10px;
}

.footer-content p {
    opacity: 0.85;
    margin-bottom: 15px;
}

.social-links {
    display: flex;
    justify-content: center;
    gap: 20px;
    margin-bottom: 20px;
}

.social-links a {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 45px;
    height: 45px;
    background: rgba(255, 255, 255, 0.1);
    border-radius: 50%;
    font-size: 1.3rem;
    transition: var(--transition);
}

.social-links a:hover {
    background: var(--secondary-color);
    transform: translateY(-3px);
}

.copyright {
    font-size: 0.85rem;
    opacity: 0.7;
    border-top: 1px solid rgba(255, 255, 255, 0.1);
    padding-top: 20px;
    margin-top: 10px;
}

/* ============================================
   RESPONSIVE DESIGN
   ============================================ */

/* Tablet */
@media (max-width: 768px) {
    .nav-links {
        display: none;
        position: absolute;
        top: 70px;
        left: 0;
        right: 0;
        background: var(--white);
        flex-direction: column;
        padding: 20px;
        box-shadow: var(--shadow);
    }

    .nav-links.active {
        display: flex;
    }

    .hamburger {
        display: flex;
    }

    .hero-content h1 {
        font-size: 2.2rem;
    }

    .hero-content p {
        font-size: 1.1rem;
    }

    .grid {
        grid-template-columns: repeat(2, 1fr);
    }
}

/* Mobile */
@media (max-width: 480px) {
    .hero {
        padding: 60px 15px;
        min-height: 50vh;
    }

    .hero-content h1 {
        font-size: 1.8rem;
    }

    .hero-content h3 {
        font-size: 0.95rem;
    }

    .btn-primary {
        padding: 12px 30px;
        font-size: 1rem;
    }

    section h2 {
        font-size: 1.5rem;
    }

    .grid {
        grid-template-columns: 1fr;
        gap: 15px;
    }

    .card {
        padding: 25px 15px;
    }
}
/* ============================================
   PAGE HEADER (Semester/Subject Pages)
   ============================================ */
.page-header {
    background: var(--bg-gradient);
    color: var(--white);
    padding: 40px 5%;
    text-align: center;
}

.header-content {
    max-width: 800px;
    margin: 0 auto;
}

.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.2);
    color: var(--white);
    padding: 10px 20px;
    border-radius: 25px;
    font-size: 0.95rem;
    margin-bottom: 20px;
    transition: var(--transition);
}

.back-btn:hover {
    background: rgba(255, 255, 255, 0.3);
    transform: translateX(-5px);
}

.page-header h1 {
    font-size: 2.5rem;
    margin-bottom: 10px;
}

.page-header h1 i {
    margin-right: 10px;
}

.page-header p {
    font-size: 1.1rem;
    opacity: 0.9;
}

/* ============================================
   SUBJECTS SECTION
   ============================================ */
.subjects-section {
    padding: 60px 5%;
    background: var(--white);
}

.subjects-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 25px;
    max-width: 1200px;
    margin: 0 auto;
}

/* ============================================
   SUBJECT CARD
   ============================================ */
.subject-card {
    background: var(--bg-light);
    border-radius: var(--border-radius);
    padding: 25px;
    display: flex;
    flex-direction: column;
    gap: 15px;
    cursor: pointer;
    transition: var(--transition);
    border: 2px solid transparent;
    box-shadow: var(--shadow);
}

.subject-card:hover {
    transform: translateY(-5px);
    border-color: var(--primary-color);
    box-shadow: var(--shadow-hover);
}

.subject-icon {
    width: 60px;
    height: 60px;
    background: var(--bg-gradient);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
}

.subject-icon i {
    font-size: 1.8rem;
    color: var(--white);
}

.subject-info {
    flex: 1;
}

.subject-code {
    display: inline-block;
    background: var(--primary-color);
    color: var(--white);
    padding: 4px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 600;
    margin-bottom: 8px;
}

.subject-info h3 {
    font-size: 1.2rem;
    color: var(--text-dark);
    margin-bottom: 5px;
}

.subject-info p {
    font-size: 0.9rem;
    color: var(--text-light);
}

.subject-status {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 15px;
    border-radius: 8px;
    font-size: 0.9rem;
    font-weight: 500;
}

.subject-status.available {
    background: #d4edda;
    color: #155724;
}

.subject-status.coming-soon {
    background: #fff3cd;
    color: #856404;
}

/* ============================================
   QUICK INFO SECTION
   ============================================ */
.quick-info {
    padding: 60px 5%;
    background: var(--bg-light);
}

.info-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 20px;
    max-width: 800px;
    margin: 0 auto;
}

.info-card {
    background: var(--white);
    padding: 30px 20px;
    text-align: center;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
}

.info-card i {
    font-size: 2rem;
    color: var(--primary-color);
    margin-bottom: 10px;
}

.info-card h3 {
    font-size: 2rem;
    color: var(--secondary-color);
    margin-bottom: 5px;
}

.info-card p {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ============================================
   OTHER SEMESTERS NAVIGATION
   ============================================ */
.other-semesters {
    padding: 60px 5%;
    background: var(--white);
    text-align: center;
}

.semester-nav {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    max-width: 800px;
    margin: 0 auto;
}

.sem-btn {
    padding: 12px 25px;
    background: var(--bg-light);
    color: var(--text-dark);
    border-radius: 25px;
    font-weight: 500;
    transition: var(--transition);
    border: 2px solid transparent;
}

.sem-btn:hover {
    background: var(--primary-color);
    color: var(--white);
}

.sem-btn.active {
    background: var(--primary-color);
    color: var(--white);
    border-color: var(--secondary-color);
}

/* ============================================
   RESPONSIVE - SEMESTER PAGE
   ============================================ */
@media (max-width: 768px) {
    .page-header h1 {
        font-size: 1.8rem;
    }
    
    .subjects-grid {
        grid-template-columns: 1fr;
    }
    
    .subject-card {
        padding: 20px;
    }
}

@media (max-width: 480px) {
    .page-header {
        padding: 30px 15px;
    }
    
    .page-header h1 {
        font-size: 1.5rem;
    }
    
    .semester-nav {
        gap: 10px;
    }
    
    .sem-btn {
        padding: 10px 18px;
        font-size: 0.9rem;
    }
}
/* ============================================
   SUBJECT HEADER
   ============================================ */
.subject-header {
    background: var(--bg-gradient);
    color: var(--white);
    padding: 40px 5%;
    text-align: center;
}

.subject-badge {
    display: inline-block;
    background: rgba(255, 255, 255, 0.2);
    padding: 8px 20px;
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 600;
    margin-bottom: 15px;
}

.subject-header h1 {
    font-size: 2.2rem;
    margin-bottom: 10px;
}

.subject-meta {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 25px;
    margin-top: 25px;
}

.meta-item {
    display: flex;
    align-items: center;
    gap: 8px;
    background: rgba(255, 255, 255, 0.15);
    padding: 10px 20px;
    border-radius: 25px;
    font-size: 0.95rem;
}

.meta-item i {
    font-size: 1.1rem;
}

/* ============================================
   TABS SECTION
   ============================================ */
.tabs-section {
    background: var(--white);
    padding: 20px 5%;
    border-bottom: 1px solid #eee;
    position: sticky;
    top: 60px;
    z-index: 100;
}

.tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 10px;
    max-width: 800px;
    margin: 0 auto;
}

.tab-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 25px;
    background: var(--bg-light);
    border: 2px solid transparent;
    border-radius: 25px;
    font-size: 1rem;
    font-weight: 500;
    color: var(--text-dark);
    cursor: pointer;
    transition: var(--transition);
}

.tab-btn:hover {
    background: var(--primary-color);
    color: var(--white);
}

.tab-btn.active {
    background: var(--primary-color);
    color: var(--white);
    border-color: var(--secondary-color);
}

/* ============================================
   TAB CONTENT
   ============================================ */
.tab-content {
    padding: 60px 5%;
    max-width: 1000px;
    margin: 0 auto;
}

.tab-content.hidden {
    display: none;
}

.tab-content h2 {
    text-align: center;
    margin-bottom: 40px;
}

/* ============================================
   UNIT CARDS (Syllabus)
   ============================================ */
.unit-card {
    background: var(--white);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow);
    margin-bottom: 20px;
    overflow: hidden;
    border-left: 4px solid var(--primary-color);
}

.unit-header {
    background: var(--bg-light);
    padding: 20px 25px;
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: 15px;
}

.unit-number {
    background: var(--primary-color);
    color: var(--white);
    padding: 6px 15px;
    border-radius: 20px;
    font-size: 0.85rem;
    font-weight: 600;
}

.unit-header h3 {
    flex: 1;
    font-size: 1.15rem;
    color: var(--text-dark);
}

.hours {
    background: var(--secondary-color);
    color: var(--white);
    padding: 5px 12px;
    border-radius: 15px;
    font-size: 0.8rem;
    font-weight: 500;
}

.unit-content {
    padding: 20px 25px;
}

.unit-content ul {
    list-style: none;
}

.unit-content li {
    padding: 10px 0;
    padding-left: 25px;
    position: relative;
    border-bottom: 1px solid #f0f0f0;
    color: var(--text-light);
}

.unit-content li:last-child {
    border-bottom: none;
}

.unit-content li::before {
    content: '✓';
    position: absolute;
    left: 0;
    color: var(--secondary-color);
    font-weight: bold;
}

/* ============================================
   NOTES GRID
   ============================================ */
.notes-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 20px;
}

.note-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 25px;
    display: flex;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    border: 2px solid transparent;
}

.note-card:hover {
    border-color: var(--primary-color);
    transform: translateY(-3px);
}

.note-card.highlight {
    background: linear-gradient(135deg, #e8f5e9 0%, #c8e6c9 100%);
    border-color: #4caf50;
}

.note-icon {
    width: 55px;
    height: 55px;
    background: #ffebee;
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
}

.note-icon i {
    font-size: 1.8rem;
    color: #e53935;
}

.note-card.highlight .note-icon {
    background: #c8e6c9;
}

.note-card.highlight .note-icon i {
    color: #2e7d32;
}

.note-info {
    flex: 1;
}

.note-info h3 {
    font-size: 1.1rem;
    color: var(--text-dark);
    margin-bottom: 5px;
}

.note-info p {
    font-size: 0.9rem;
    color: var(--text-light);
    margin-bottom: 5px;
}

.file-size {
    font-size: 0.8rem;
    color: #999;
}

.download-btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 20px;
    background: var(--primary-color);
    color: var(--white);
    border-radius: 25px;
    font-size: 0.9rem;
    font-weight: 500;
    transition: var(--transition);
    white-space: nowrap;
}

.download-btn:hover {
    background: var(--primary-dark);
    transform: scale(1.05);
}

.download-btn.coming-soon-btn {
    background: #9e9e9e;
    cursor: not-allowed;
}

.download-btn.coming-soon-btn:hover {
    transform: none;
}

/* ============================================
   PYQ GRID
   ============================================ */
.pyq-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 20px;
}

.pyq-card {
    background: var(--white);
    border-radius: var(--border-radius);
    padding: 25px;
    display: flex;
    align-items: center;
    gap: 20px;
    box-shadow: var(--shadow);
    transition: var(--transition);
}

.pyq-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-hover);
}

.pyq-year {
    width: 60px;
    height: 60px;
    background: var(--bg-gradient);
    color: var(--white);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
    font-weight: bold;
}

.pyq-info {
    flex: 1;
}

.pyq-info h3 {
    font-size: 1.1rem;
    margin-bottom: 5px;
}

.pyq-info p {
    font-size: 0.9rem;
    color: var(--text-light);
}

/* ============================================
   VIDEO NOTICE
   ============================================ */
.video-notice {
    text-align: center;
    padding: 60px 30px;
    background: var(--bg-light);
    border-radius: var(--border-radius);
}

.video-notice i {
    font-size: 4rem;
    color: var(--primary-color);
    margin-bottom: 20px;
}

.video-notice h3 {
    font-size: 1.5rem;
    margin-bottom: 10px;
}

.video-notice p {
    color: var(--text-light);
}

/* ============================================
   RELATED SUBJECTS
   ============================================ */
.related-subjects {
    padding: 60px 5%;
    background: var(--bg-light);
}

.related-grid {
    display: flex;
    flex-wrap: wrap;
    justify-content: center;
    gap: 15px;
    max-width: 900px;
    margin: 0 auto;
}

.related-card {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px 25px;
    background: var(--white);
    border-radius: 30px;
    box-shadow: var(--shadow);
    transition: var(--transition);
    font-weight: 500;
}

.related-card:hover {
    background: var(--primary-color);
    color: var(--white);
    transform: translateY(-3px);
}

.related-card i {
    font-size: 1.2rem;
}

/* ============================================
   RESPONSIVE - SUBJECT PAGE
   ============================================ */
@media (max-width: 768px) {
    .subject-header h1 {
        font-size: 1.6rem;
    }
    
    .subject-meta {
        gap: 10px;
    }
    
    .meta-item {
        padding: 8px 15px;
        font-size: 0.85rem;
    }
    
    .tabs {
        gap: 8px;
    }
    
    .tab-btn {
        padding: 10px 18px;
        font-size: 0.9rem;
    }
    
    .note-card {
        flex-direction: column;
        text-align: center;
    }
    
    .notes-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .tabs-section {
        top: 55px;
    }
    
    .tab-btn {
        padding: 8px 12px;
        font-size: 0.8rem;
    }
    
    .tab-btn i {
        display: none;
    }
    
    .unit-header {
        flex-direction: column;
        align-items: flex-start;
        gap: 10px;
    }
}
/* ============================================
   SUBJECT SELECTION (For Remedial Page)
   ============================================ */
.subject-selection {
    padding: 30px 5%;
    background: var(--white);
    text-align: center;
}

.subject-selection h2 {
    margin-bottom: 20px;
}

.selection-tabs {
    display: flex;
    justify-content: center;
    flex-wrap: wrap;
    gap: 15px;
}

.selection-btn {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 15px 30px;
    background: var(--bg-light);
    border: 2px solid transparent;
    border-radius: 30px;
    font-size: 1.1rem;
    font-weight: 600;
    color: var(--text-dark);
    cursor: pointer;
    transition: var(--transition);
}

.selection-btn:hover {
    background: var(--primary-color);
    color: var(--white);
}

.selection-btn.active {
    background: var(--primary-color);
    color: var(--white);
    border-color: var(--secondary-color);
}

.selection-btn i {
    font-size: 1.3rem;
}

/* Subject Content Visibility */
.subject-content.hidden {
    display: none;
}

/* ============================================
   RESPONSIVE - SUBJECT SELECTION
   ============================================ */
@media (max-width: 480px) {
    .selection-btn {
        padding: 12px 20px;
        font-size: 0.95rem;
    }
    
    .selection-btn i {
        font-size: 1.1rem;
    }
}