.activity-page {
    background: #f8f9fa;
    min-height: 100vh;
}

.activity-hero {
    position: relative;
    height: 280px;
    background-color: #0a1e42;
    background-position: center center;
    background-size: cover;
    background-repeat: no-repeat;
}

.activity-hero::before {
    content: '';
    position: absolute;
    inset: 0;
    background: linear-gradient(to bottom, rgba(10, 30, 66, 0.4) 0%, rgba(10, 30, 66, 0.85) 100%);
}

.activity-hero-content {
    position: relative;
    z-index: 1;
    max-width: 1200px;
    margin: 0 auto;
    padding: 40px;
    padding-bottom: 60px;
    height: 100%;
    display: flex;
    flex-direction: column;
    justify-content: center;
}

.activity-hero .breadcrumb {
    display: flex;
    align-items: center;
    gap: 8px;
    font-size: 13px;
    margin-bottom: 12px;
}

.activity-hero .breadcrumb a {
    color: rgba(255, 255, 255, 0.7);
    text-decoration: none;
    transition: color 0.2s;
}

.activity-hero .breadcrumb a:hover {
    color: #ffffff;
}

.activity-hero .breadcrumb-separator {
    color: rgba(255, 255, 255, 0.4);
}

.activity-hero .breadcrumb-current {
    color: #ffffff;
}

.activity-hero h1 {
    font-family: 'Rubik', sans-serif;
    font-size: 36px;
    font-weight: 700;
    color: #ffffff;
    margin: 0 0 16px 0;
}

.activity-hero-badges {
    display: flex;
    gap: 10px;
    flex-wrap: wrap;
}

.hero-badge {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border-radius: 20px;
    font-family: 'Inter', sans-serif;
    font-size: 12px;
    font-weight: 600;
    background: rgba(255, 255, 255, 0.15);
    color: #ffffff;
    backdrop-filter: blur(8px);
}

.hero-badge i {
    font-size: 11px;
}

.activity-container {
    max-width: 1200px;
    margin: 0 auto;
    padding: 0 40px 80px;
}

.tabs-wrapper {
    background: #ffffff;
    border-radius: 0 0 16px 16px;
    box-shadow: 0 4px 20px rgba(0, 0, 0, 0.08);
    margin-top: 0;
    position: relative;
    z-index: 10;
    overflow: hidden;
}

.tab-nav {
    display: flex;
    align-items: center;
    border-bottom: 1px solid #e5e7eb;
    background: #fafafa;
    overflow-x: auto;
}

.tab-nav-main {
    display: flex;
    flex: 1;
}

.tab-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 18px 24px;
    background: none;
    border: none;
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    font-weight: 500;
    color: #6b7280;
    cursor: pointer;
    white-space: nowrap;
    transition: all 0.2s;
    position: relative;
}

.tab-btn:hover {
    color: #374151;
    background: #f3f4f6;
}

.tab-btn.active {
    color: #ea580c;
    background: #ffffff;
}

.tab-btn.active::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    height: 3px;
    background: #ea580c;
}

.tab-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
    color: #9ca3af;
}

.tab-btn i {
    font-size: 14px;
}

.tab-content {
    display: none;
    padding: 40px 60px;
}

.tab-content.active {
    display: block;
}

.activity-nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 24px 40px;
    border-top: 1px solid #e5e7eb;
    background: #fafafa;
}

.nav-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border-radius: 10px;
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    font-weight: 600;
    cursor: pointer;
    transition: all 0.2s;
}

.nav-btn-back {
    background: #ffffff;
    border: 2px solid #e5e7eb;
    color: #6b7280;
}

.nav-btn-back:hover:not(:disabled) {
    border-color: #d1d5db;
    color: #374151;
}

.nav-btn-next {
    background: #ea580c;
    border: 2px solid #ea580c;
    color: #ffffff;
}

.nav-btn-next:hover:not(:disabled) {
    background: #fa7c38;
    border-color: #fa7c38;
}

.nav-btn:disabled {
    opacity: 0.4;
    cursor: not-allowed;
}

.nav-btn-back.hidden {
    visibility: hidden;
}

.intro-grid {
    display: grid;
    grid-template-columns: 1fr auto;
    gap: 32px;
    align-items: start;
}

.intro-main {
    display: flex;
    flex-direction: column;
    gap: 24px;
}

.intro-text {
    font-family: 'Inter', sans-serif;
    font-size: 15px;
    line-height: 1.8;
    color: #4b5563;
}

.intro-text strong {
    color: #ea580c;
}

.intro-sidebar {
    display: flex;
    flex-direction: column;
    gap: 16px;
    max-width: 380px;
}

.info-card {
    background: #f9fafb;
    border: 1px solid #e5e7eb;
    border-radius: 12px;
    padding: 12px;
    display: flex;
    gap: 10px;
}

.info-card-icon {
    width: 36px;
    height: 36px;
    border-radius: 8px;
    background: #ffedd5;
    color: #ea580c;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    flex-shrink: 0;
}

.info-card-content h4 {
    font-family: 'Rubik', sans-serif;
    font-size: 14px;
    font-weight: 600;
    color: #374151;
    margin: 0 0 4px 0;
}

.info-card-content p {
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    color: #6b7280;
    margin: 0;
}

.exercise-section {
    margin-bottom: 40px;
}

.exercise-header {
    display: flex;
    align-items: center;
    gap: 16px;
    margin-bottom: 20px;
}

.exercise-number {
    width: 36px;
    height: 36px;
    border-radius: 50%;
    background: #ea580c;
    color: #ffffff;
    font-family: 'Rubik', sans-serif;
    font-size: 16px;
    font-weight: 700;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.exercise-header h3 {
    font-family: 'Rubik', sans-serif;
    font-size: 20px;
    font-weight: 600;
    color: #1f2937;
    margin: 0;
}

.exercise-instructions {
    font-family: 'Inter', sans-serif;
    font-size: 15px;
    color: #6b7280;
    margin-bottom: 20px;
    line-height: 1.6;
}

@media (max-width: 768px) {
    .activity-hero {
        height: 220px;
    }

    .activity-hero-content {
        padding: 24px;
    }

    .activity-hero h1 {
        font-size: 28px;
    }

    .activity-container {
        padding: 0 16px 60px;
    }

    .tab-nav {
        gap: 0;
        flex-wrap: wrap;
    }

    .tab-nav-main {
        width: 100%;
    }

    .tab-content {
        padding: 24px;
    }

    .activity-nav {
        padding: 16px 24px;
    }

    .nav-btn {
        padding: 10px 18px;
        font-size: 13px;
    }
}

.tip-box {
    background-color: #e2f4f6; 
    border: 1px solid #7ebcc9; 
    border-radius: 0.75rem;  
    padding: 1rem;  
    margin-top: 24px; 
}

.tip-header {
    display: flex;
    align-items: center;
    gap: 8px;
    margin-bottom: 8px;
    font-family: 'Inter', sans-serif;
    font-weight: 700;
    color: #2c718a;
    font-size: 15px;           
}

.tip-content {
    font-family: 'Inter', sans-serif;
    font-size: 0.875rem;
    color: #3b8a9d; 
    line-height: 1.6;          
}

.tip-content ul {
    margin: 8px 0;            
    padding-left: 20px;
    list-style-type: disc;
}

.tip-content li {
    margin-bottom: 4px;        
}

.warning-box {
    background: #fef9c3;
    border: 1px solid #fde047;
    border-radius: 10px;
    padding: 12px 16px;
    margin-bottom: 32px;
    display: flex;
    gap: 12px;
    align-items: center;
}

.warning-box i {
    color: #ca8a04;
    font-size: 16px;
}

.warning-box-content h4,
.warning-box-content p {
    font-family: 'Inter', sans-serif;
    font-size: 14px;
    margin: 0;
    display: inline;
}

.warning-box-content h4 {
    font-weight: 600;
    color: #854d0e;
}

.warning-box-content p {
    color: #a16207;
}

.completion-box {
    position: relative;
    background: #ffffff;
    border-radius: 16px;
    border: 2px solid #16a34a;
    max-width: 100%;
    width: 100%;
    overflow: hidden;
    box-shadow: 0 4px 20px rgba(22, 163, 74, 0.12);
    margin-top: 32px;
}

.completion-bar {
    height: 4px;
    background: linear-gradient(90deg, #16a34a, #22c55e);
    width: 100%;
}

.completion-inner {
    padding: 1.25rem 1.5rem 1.5rem;
}

.completion-header {
    display: flex;
    align-items: center;
    gap: 10px;
    margin-bottom: 0.4rem;
}

.completion-icon {
    width: 36px;
    height: 36px;
    background: linear-gradient(135deg, #16a34a, #22c55e);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.completion-icon svg {
    width: 16px;
    height: 16px;
    stroke: white;
    stroke-width: 2.5;
    fill: none;
}

.completion-title {
    font-family: 'Rubik', sans-serif;
    font-size: 1.15rem;
    font-weight: 700;
    color: #15803d;
    line-height: 1.2;
    margin: 0;
}

.completion-subtitle {
    font-family: 'Inter', sans-serif;
    font-size: 0.82rem;
    color: #6b7280;
    margin-top: 0;
    margin-bottom: 1rem;
    line-height: 1.5;
}

.completion-subtitle strong {
    color: #15803d;
    font-weight: 600;
}

.skills-list {
    display: flex;
    flex-direction: column;
    gap: 0.4rem;
}

.skill-item {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 0.5rem 0.85rem;
    background: #f0fdf4;
    border: 1px solid #bbf7d0;
    border-radius: 10px;
    font-size: 0.8rem;
    color: #166534;
    font-weight: 500;
    font-family: 'Inter', sans-serif;
}

.skill-check {
    width: 16px;
    height: 16px;
    background: #16a34a;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
}

.skill-check svg {
    width: 8px;
    height: 8px;
    stroke: white;
    stroke-width: 2.5;
    fill: none;
}