/* stilurile pentru paginile de cursuri */

/* variabilele CSS pentru culori si setari */
:root {
    --primary-color: #6366f1;
    --secondary-color: #8b5cf6;
    --success-color: #22c55e;
    --warning-color: #f59e0b;
    --error-color: #ef4444;
    --text-primary: #1f2937;
    --text-secondary: #6b7280;
    --bg-primary: #ffffff;
    --bg-secondary: #f9fafb;
    --bg-tertiary: #f3f4f6;
    --border-color: #e5e7eb;
    --shadow-sm: 0 1px 2px 0 rgb(0 0 0 / 0.05);
    --shadow-md: 0 4px 6px -1px rgb(0 0 0 / 0.1);
    --shadow-lg: 0 10px 15px -3px rgb(0 0 0 / 0.1);
    --border-radius: 8px;
    --border-radius-lg: 12px;
    --transition: all 0.3s ease;
}

/* reset-ul pentru toate elementele */
* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

/* stilurile pentru body cu gradient de fundal */
body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
    line-height: 1.6;
    color: var(--text-primary);
    background: linear-gradient(135deg, #667eea 0%, #764ba2 100%);
    min-height: 100vh;
    padding: 2rem 1rem;
}

/* containerul principal pentru curs */
.course-container {
    max-width: 1000px;
    margin: 0 auto;
    background: var(--bg-primary);
    border-radius: var(--border-radius-lg);
    box-shadow: var(--shadow-lg);
    overflow: hidden;
    animation: slideIn 0.6s ease-out;
}

/* animatia pentru aparitia containerului */
@keyframes slideIn {
    from {
        opacity: 0;
        transform: translateY(20px);
    }
    to {
        opacity: 1;
        transform: translateY(0);
    }
}

/* header-ul cursului cu gradient si pattern */
.course-header {
    background: linear-gradient(135deg, var(--primary-color), var(--secondary-color));
    color: white;
    padding: 3rem 2rem;
    text-align: center;
    position: relative;
    overflow: hidden;
}

/* pattern-ul de fundal pentru header */
.course-header::before {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: url('data:image/svg+xml,<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 100 100"><circle cx="20" cy="20" r="2" fill="rgba(255,255,255,0.1)"/><circle cx="80" cy="80" r="2" fill="rgba(255,255,255,0.1)"/><circle cx="40" cy="60" r="1" fill="rgba(255,255,255,0.1)"/></svg>');
    opacity: 0.3;
}

/* titlul cursului */
.course-header h1 {
    font-size: 2.5rem;
    font-weight: 700;
    margin-bottom: 0.5rem;
    position: relative;
    z-index: 1;
}

/* descrierea cursului */
.course-header p {
    font-size: 1.2rem;
    opacity: 0.9;
    position: relative;
    z-index: 1;
}

/* indicatorul de progres */
.progress-indicator {
    display: flex;
    align-items: center;
    justify-content: center;
    margin-top: 1.5rem;
    position: relative;
    z-index: 1;
}

.progress-bar {
    width: 200px;
    height: 8px;
    background: rgba(255, 255, 255, 0.2);
    border-radius: 4px;
    margin: 0 1rem;
    overflow: hidden;
}

.progress-fill {
    height: 100%;
    background: rgba(255, 255, 255, 0.8);
    border-radius: 4px;
    transition: width 0.3s ease;
    width: 0%;
}

.lesson-content {
    padding: 2.5rem;
    background: var(--bg-primary);
}

.lesson-section {
    margin-bottom: 2.5rem;
}

.lesson-section h2 {
    color: var(--primary-color);
    font-size: 1.8rem;
    font-weight: 600;
    margin-bottom: 1rem;
    display: flex;
    align-items: center;
    gap: 0.5rem;
}

.lesson-section h3 {
    color: var(--text-primary);
    font-size: 1.4rem;
    font-weight: 600;
    margin: 1.5rem 0 1rem 0;
}

.lesson-section p {
    color: var(--text-secondary);
    margin-bottom: 1rem;
    font-size: 1.1rem;
}

.lesson-section ul {
    color: var(--text-secondary);
    margin: 1rem 0;
    padding-left: 1.5rem;
}

.lesson-section li {
    margin-bottom: 0.5rem;
}

.code-example {
    background: #1e293b;
    color: #e2e8f0;
    padding: 1.5rem;
    border-radius: var(--border-radius);
    margin: 1.5rem 0;
    font-family: 'Fira Code', 'Courier New', monospace;
    font-size: 0.9rem;
    line-height: 1.5;
    overflow-x: auto;
    border-left: 4px solid var(--primary-color);
    position: relative;
}

.code-example::before {
    content: 'CODE';
    position: absolute;
    top: 0.5rem;
    right: 1rem;
    font-size: 0.7rem;
    color: var(--primary-color);
    font-weight: 600;
    letter-spacing: 1px;
}

.demo-box {
    background: var(--bg-secondary);
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.interactive-demo {
    background: linear-gradient(135deg, var(--bg-secondary), var(--bg-tertiary));
    border: 2px solid var(--primary-color);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin: 1.5rem 0;
}

.interactive-demo h4 {
    color: var(--primary-color);
    margin-bottom: 1rem;
    font-weight: 600;
}

.demo-button {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    margin: 0.25rem;
    transition: var(--transition);
    font-size: 0.9rem;
}

.demo-button:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
}

.demo-input {
    border: 2px solid var(--border-color);
    border-radius: var(--border-radius);
    padding: 0.75rem;
    margin: 0.25rem;
    font-size: 1rem;
    transition: var(--transition);
}

.demo-input:focus {
    outline: none;
    border-color: var(--primary-color);
    box-shadow: 0 0 0 3px rgba(99, 102, 241, 0.1);
}

.output {
    background: #1e293b;
    color: #22c55e;
    padding: 1rem;
    border-radius: var(--border-radius);
    font-family: 'Fira Code', monospace;
    margin-top: 1rem;
    white-space: pre-line;
    border-left: 4px solid var(--success-color);
}

.quiz-container {
    background: linear-gradient(135deg, var(--text-primary), #374151);
    color: white;
    padding: 2.5rem;
    margin-top: 2rem;
}

.quiz-header {
    text-align: center;
    margin-bottom: 2rem;
}

.quiz-header h2 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.quiz-question {
    background: rgba(255, 255, 255, 0.05);
    border-radius: var(--border-radius);
    padding: 1.5rem;
    margin-bottom: 1.5rem;
    border-left: 4px solid var(--primary-color);
}

.quiz-question h3 {
    font-size: 1.2rem;
    margin-bottom: 1rem;
    color: white;
}

.quiz-options {
    display: grid;
    gap: 0.75rem;
    margin-bottom: 1rem;
}

.quiz-option {
    padding: 1rem 1.5rem;
    background: rgba(255, 255, 255, 0.1);
    border: 2px solid transparent;
    border-radius: var(--border-radius);
    color: white;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    font-size: 1rem;
}

.quiz-option:hover {
    background: rgba(255, 255, 255, 0.2);
    transform: translateX(5px);
}

.quiz-option.selected {
    background: rgba(99, 102, 241, 0.3);
    border-color: var(--primary-color);
}

.quiz-option.correct {
    background: var(--success-color);
    border-color: var(--success-color);
}

.quiz-option.incorrect {
    background: var(--error-color);
    border-color: var(--error-color);
}

.quiz-submit {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 1rem 2rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-size: 1.1rem;
    font-weight: 600;
    transition: var(--transition);
    display: block;
    margin: 2rem auto 0;
}

.quiz-submit:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
    box-shadow: var(--shadow-lg);
}

.quiz-result {
    display: none;
    padding: 1.5rem;
    margin-top: 1.5rem;
    border-radius: var(--border-radius);
    text-align: center;
    font-weight: 600;
}

.quiz-result.show {
    display: block;
    animation: fadeIn 0.5s ease-out;
}

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

.quiz-result.pass {
    background: var(--success-color);
    color: white;
}

.quiz-result.fail {
    background: var(--warning-color);
    color: white;
}

.navigation-buttons {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 2rem;
    background: var(--bg-secondary);
    border-top: 1px solid var(--border-color);
}

.nav-btn {
    background: var(--primary-color);
    color: white;
    border: none;
    padding: 0.75rem 1.5rem;
    border-radius: var(--border-radius);
    cursor: pointer;
    font-weight: 500;
    transition: var(--transition);
    text-decoration: none;
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
}

.nav-btn:hover {
    background: var(--secondary-color);
    transform: translateY(-2px);
}

.nav-btn:disabled {
    background: var(--text-secondary);
    cursor: not-allowed;
    transform: none;
}

.course-info {
    display: flex;
    align-items: center;
    gap: 1rem;
    color: var(--text-secondary);
    font-size: 0.9rem;
}

@media (max-width: 768px) {
    body {
        padding: 1rem 0.5rem;
    }
    
    .course-header h1 {
        font-size: 2rem;
    }
    
    .lesson-content {
        padding: 1.5rem;
    }
    
    .quiz-container {
        padding: 1.5rem;
    }
    
    .navigation-buttons {
        flex-direction: column;
        gap: 1rem;
    }
    
    .course-info {
        order: -1;
    }
}