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

body {
    font-family: 'Segoe UI', Tahoma, Geneva, Verdana, sans-serif;
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    color: #333;
}

.container {
    max-width: 1400px;
    margin: 0 auto;
    padding: 20px;
}

/* Header */
.header {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 20px 30px;
    margin-bottom: 30px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 15px;
    font-size: 28px;
    font-weight: bold;
    color: #667eea;
}

.logo i {
    font-size: 36px;
}

.nav-links {
    display: flex;
    gap: 30px;
    align-items: center;
    position: absolute;
    left: 50%;
    transform: translateX(-50%);
}

.nav-link {
    color: #555;
    text-decoration: none;
    font-weight: 500;
    padding: 10px 20px;
    border-radius: 12px;
    transition: all 0.3s ease;
    position: relative;
    overflow: hidden;
}

.lesson-plans-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 20px;
    padding: 15px 20px;
    background: rgba(102, 126, 234, 0.1);
    border-radius: 10px;
    border-left: 4px solid #667eea;
}

.lesson-plans-header h3 {
    color: #667eea;
    margin: 0;
    font-size: 20px;
}

.refresh-btn {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    border: none;
    padding: 10px 20px;
    border-radius: 8px;
    cursor: pointer;
    display: flex;
    align-items: center;
    gap: 8px;
    font-weight: 600;
    transition: all 0.3s ease;
    font-size: 14px;
}

.refresh-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.3);
}

.refresh-btn i {
    transition: transform 0.3s ease;
}

.refresh-btn:active i {
    transform: rotate(180deg);
}

.plan-indicator {
    background: rgba(118, 75, 162, 0.2);
    color: #764ba2;
    padding: 5px 10px;
    border-radius: 15px;
    font-size: 12px;
    font-weight: 600;
    margin-left: 10px;
}

.plan-version {
    color: #764ba2;
    font-size: 14px;
    font-weight: normal;
    font-style: italic;
}

.nav-link:hover {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    transform: translateY(-2px);
}


/* Main Content Card */
.main-card {
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    padding: 40px;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    margin-bottom: 30px;
    animation: fadeInUp 0.6s ease-out;
}

.page-title {
    font-size: 36px;
    font-weight: bold;
    margin-bottom: 10px;
    color: #333;
    text-align: center;
    position: relative;
}

.page-subtitle {
    font-size: 18px;
    color: #666;
    text-align: center;
    margin-bottom: 40px;
}

/* Back Button */
.back-btn {
    display: inline-flex;
    align-items: center;
    gap: 10px;
    padding: 15px 30px;
    background: rgba(255, 255, 255, 0.95);
    color: #667eea;
    text-decoration: none;
    border-radius: 15px;
    font-weight: 600;
    transition: all 0.3s ease;
    box-shadow: 0 8px 32px rgba(0, 0, 0, 0.1);
    margin-bottom: 20px;
}

.back-btn:hover {
    transform: translateY(-3px);
    box-shadow: 0 15px 40px rgba(0, 0, 0, 0.2);
}

/* Program Toggle */
.program-toggle {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 30px;
    gap: 10px;
    flex-wrap: wrap;
}

.toggle-wrapper {
    display: flex;
    align-items: center;
    background: rgba(102, 126, 234, 0.1);
    border-radius: 25px;
    padding: 5px;
    border: 2px solid #667eea;
    gap: 5px;
}

.toggle-option {
    padding: 12px 25px;
    font-weight: 600;
    border-radius: 20px;
    cursor: pointer;
    transition: all 0.3s ease;
    color: #667eea;
    display: flex;
    align-items: center;
    gap: 8px;
    white-space: nowrap;
}

.toggle-option.active {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    box-shadow: 0 4px 15px rgba(102, 126, 234, 0.3);
}

.toggle-option:not(.active):hover {
    background: rgba(102, 126, 234, 0.2);
}

/* Content Sections */
.program-content {
    display: none;
    animation: fadeInUp 0.5s ease-out;
}

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

.program-header {
    text-align: center;
    margin-bottom: 30px;
    padding: 25px;
    background: linear-gradient(135deg, rgba(102, 126, 234, 0.1), rgba(118, 75, 162, 0.1));
    border-radius: 15px;
    border-left: 4px solid #667eea;
}

.program-header h2 {
    color: #667eea;
    font-size: 28px;
    margin-bottom: 10px;
}

.program-header p {
    color: #666;
    font-size: 16px;
    line-height: 1.6;
}

/* Collapsible Sections */
.collapsible-section {
    margin-bottom: 20px;
    border-radius: 15px;
    overflow: hidden;
    box-shadow: 0 4px 15px rgba(0, 0, 0, 0.1);
}

.collapsible-header {
    background: linear-gradient(135deg, #667eea, #764ba2);
    color: white;
    padding: 20px 25px;
    cursor: pointer;
    display: flex;
    justify-content: space-between;
    align-items: center;
    transition: all 0.3s ease;
    font-weight: 600;
    font-size: 18px;
}

.collapsible-header:hover {
    background: linear-gradient(135deg, #5a6fd8, #6b4190);
}

.collapsible-header i {
    transition: transform 0.3s ease;
}

.collapsible-header.active i {
    transform: rotate(180deg);
}

.collapsible-content {
    background: white;
    padding: 0;
    max-height: 0;
    overflow: hidden;
    transition: all 0.3s ease;
}

.collapsible-content.active {
    padding: 25px;
    max-height: none;
    overflow: visible;
}

.skills-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.skill-item {
    background: rgba(102, 126, 234, 0.1);
    border-radius: 10px;
    border-left: 4px solid #667eea;
    transition: all 0.3s ease;
    cursor: pointer;
    perspective: 1000px;
    height: 200px;
    position: relative;
}

.skill-item:hover {
    transform: translateY(-2px);
    box-shadow: 0 5px 15px rgba(102, 126, 234, 0.2);
}

.skill-card {
    position: relative;
    width: 100%;
    height: 100%;
    transform-style: preserve-3d;
    transition: transform 0.6s ease;
}

.skill-item.flipped .skill-card {
    transform: rotateY(180deg);
}

.skill-front, .skill-back {
    position: absolute;
    width: 100%;
    height: 100%;
    backface-visibility: hidden;
    border-radius: 10px;
    padding: 15px;
    display: flex;
    flex-direction: column;
}

.skill-front {
    background: rgba(102, 126, 234, 0.1);
    justify-content: center;
}

.skill-back {
    background: rgba(118, 75, 162, 0.1);
    transform: rotateY(180deg);
    justify-content: center;
    align-items: center;
}

.skill-front h4 {
    color: #667eea;
    margin-bottom: 8px;
    font-size: 16px;
}

.skill-front p {
    color: #666;
    font-size: 14px;
    line-height: 1.5;
    flex-grow: 1;
}

.flip-hint {
    color: #667eea;
    font-size: 12px;
    text-align: center;
    margin-top: 10px;
    font-style: italic;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
}

.skill-video {
    width: 100%;
    height: 120px;
    border-radius: 8px;
    object-fit: cover;
    margin-bottom: 10px;
}

.video-placeholder {
    width: 100%;
    height: 120px;
    background: linear-gradient(135deg, #667eea, #764ba2);
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 24px;
    margin-bottom: 10px;
}

.video-title {
    color: #764ba2;
    font-size: 14px;
    font-weight: 600;
    text-align: center;
}

.back-to-description {
    color: #764ba2;
    font-size: 12px;
    text-align: center;
    margin-top: 5px;
    font-style: italic;
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 5px;
}

.lesson-plan {
    background: rgba(118, 75, 162, 0.1);
    padding: 20px;
    border-radius: 10px;
    margin-bottom: 15px;
    border-left: 4px solid #764ba2;
}

.lesson-plan h4 {
    color: #764ba2;
    margin-bottom: 10px;
    font-size: 18px;
}

.lesson-plan ul {
    margin-left: 20px;
    color: #666;
}

.lesson-plan li {
    margin-bottom: 5px;
    line-height: 1.5;
}

/* Footer */
.footer {
    text-align: center;
    padding: 30px 20px;
    background: rgba(255, 255, 255, 0.95);
    backdrop-filter: blur(10px);
    border-radius: 20px;
    color: #666;
}

.footer a {
    color: #667eea;
    text-decoration: none;
    margin: 0 10px;
}

.footer a:hover {
    text-decoration: underline;
}

/* Responsive Design */
@media (max-width: 1024px) {
    .nav-links {
        display: none;
    }
}

@media (max-width: 768px) {
    .skill-item {
        height: auto;
        min-height: 200px;
    }

    .collapsible-content.active {
        padding: 15px;
    }

    .lesson-plan {
        padding: 15px;
        margin-bottom: 10px;
    }

    .lesson-plans-header {
        flex-direction: column;
        gap: 15px;
        text-align: center;
    }

    .refresh-btn {
        width: 100%;
        justify-content: center;
    }

    .header {
        padding: 15px 20px;
    }

    .logo {
        font-size: 20px;
    }

    .container {
        padding: 15px;
    }

    .main-card {
        padding: 25px;
    }

    .page-title {
        font-size: 28px;
    }

    .toggle-wrapper {
        flex-direction: column;
        width: 100%;
    }

    .toggle-option {
        width: 100%;
        justify-content: center;
    }

    .skills-grid {
        grid-template-columns: 1fr;
    }
}

@media (max-width: 480px) {
    .container {
        padding: 10px;
    }

    .main-card {
        padding: 15px;
    }

    .page-title {
        font-size: 24px;
    }

    .page-subtitle {
        font-size: 16px;
    }

    .program-header {
        padding: 15px;
    }

    .program-header h2 {
        font-size: 22px;
    }

    .collapsible-header {
        padding: 15px 20px;
        font-size: 16px;
    }

    .collapsible-content.active {
        padding: 10px;
    }

    .skill-front h4 {
        font-size: 14px;
    }

    .skill-front p {
        font-size: 12px;
    }

    .lesson-plan {
        padding: 12px;
    }

    .lesson-plan h4 {
        font-size: 16px;
    }

    .lesson-plans-header h3 {
        font-size: 18px;
    }

    .back-btn {
        padding: 12px 20px;
        font-size: 14px;
    }
}

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