:root {
    --primary-teal: #2C6666;
    --secondary-teal: #66cccc;
    --light-teal: #80dddd;
    --accent-teal: #99e6e6;
    --dark-teal: #1a4d4d;
    --text-primary: #2c3e50;
    --text-secondary: #546e7a;
    --background-light: #f8fafa;
    --white: #ffffff;
    --border-light: #e0f2f1;
    --shadow-light: 0 2px 10px rgba(44, 102, 102, 0.1);
    --shadow-medium: 0 4px 20px rgba(44, 102, 102, 0.15);
    --shadow-heavy: 0 8px 30px rgba(44, 102, 102, 0.2);
    --border-radius: 12px;
    --border-radius-large: 16px;
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
    box-sizing: border-box;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    margin: 0;
    padding: 0;
    background: linear-gradient(135deg, var(--background-light) 0%, #e8f5f5 100%);
    color: var(--text-primary);
    line-height: 1.6;
    display: flex;
    flex-direction: column;
    min-height: 100vh;
    font-weight: 400;
}

/* Global Layout */
.container {
    display: flex;
    flex: 1;
    width: 100vw;
    max-width: none;
    margin: 0 auto;
    background-color: var(--white);
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-medium);
    overflow: hidden;
    height: calc(100vh - 40px);
    backdrop-filter: blur(10px);
}

/* Sidebar Navigation */
.sidebar {
    width: 300px;
    background: linear-gradient(180deg, var(--white) 0%, var(--background-light) 100%);
    padding: 30px 25px;
    border-right: 1px solid var(--border-light);
    display: flex;
    flex-direction: column;
    box-shadow: 4px 0 20px rgba(44, 102, 102, 0.08);
    flex-shrink: 0;
}

.sidebar h2 {
    font-size: 1.6rem;
    color: var(--primary-teal);
    margin-bottom: 30px;
    font-weight: 700;
    text-align: center;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.progress-bar-container {
    width: 100%;
    background-color: var(--border-light);
    border-radius: 25px;
    overflow: hidden;
    margin-bottom: 25px;
    height: 12px;
    box-shadow: inset 0 2px 4px rgba(44, 102, 102, 0.1);
}

.progress-bar {
    height: 100%;
    width: 0%;
    background: linear-gradient(90deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    border-radius: 25px;
    transition: width 0.6s cubic-bezier(0.4, 0, 0.2, 1);
    position: relative;
    overflow: hidden;
}

.progress-bar::after {
    content: '';
    position: absolute;
    top: 0;
    left: 0;
    right: 0;
    bottom: 0;
    background: linear-gradient(45deg, transparent 30%, rgba(255,255,255,0.3) 50%, transparent 70%);
    animation: shimmer 2s infinite;
}

@keyframes shimmer {
    0% { transform: translateX(-100%); }
    100% { transform: translateX(100%); }
}

.progress-text {
    font-size: 0.95rem;
    color: var(--text-secondary);
    margin-top: 8px;
    margin-bottom: 20px;
    text-align: center;
    font-weight: 500;
}

.nav-list {
    list-style: none;
    padding: 0;
    flex-grow: 1;
    overflow-y: auto;
}

.nav-list li {
    margin-bottom: 8px;
}

.nav-list a {
    display: block;
    padding: 14px 18px;
    color: var(--text-primary);
    text-decoration: none;
    border-radius: var(--border-radius);
    transition: var(--transition);
    font-weight: 500;
    font-size: 0.95rem;
    border: 2px solid transparent;
    position: relative;
    overflow: hidden;
}

.nav-list a::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(102, 204, 204, 0.1), transparent);
    transition: left 0.5s;
}

.nav-list a:hover::before {
    left: 100%;
}

.nav-list a.active,
.nav-list a:hover {
    background: linear-gradient(135deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    color: var(--white);
    transform: translateX(4px);
    box-shadow: var(--shadow-light);
    border-color: var(--secondary-teal);
}

.nav-list a.disabled {
    pointer-events: none;
    opacity: 0.5;
    cursor: not-allowed;
    background-color: var(--background-light);
}

/* Main Content Area */
.main-content {
    flex: 1;
    padding: 50px;
    overflow-y: auto;
    width: 100%;
    margin: 0;
    box-sizing: border-box;
    background: linear-gradient(180deg, var(--white) 0%, var(--background-light) 100%);
}

.main-content h1 {
    font-size: 2.8rem;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 15px;
    font-weight: 700;
    line-height: 1.2;
}

.main-content .subtitle-info {
    font-size: 1.1rem;
    color: var(--text-secondary);
    margin-bottom: 40px;
    font-family: 'Roboto', sans-serif;
    font-weight: 500;
}

.content-section {
    margin-bottom: 50px;
    display: none;
    animation: fadeInUp 0.6s ease-out;
}

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

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

.content-section h2 {
    font-size: 2rem;
    color: var(--secondary-teal);
    margin-bottom: 25px;
    font-weight: 600;
    position: relative;
    padding-bottom: 10px;
}

.content-section h2::after {
    content: '';
    position: absolute;
    bottom: 0;
    left: 0;
    width: 60px;
    height: 3px;
    background: linear-gradient(90deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    border-radius: 2px;
}

.content-section p {
    margin-bottom: 20px;
    font-size: 1.1rem;
    line-height: 1.8;
    text-align: justify;
    color: var(--text-primary);
    transition: var(--transition);
}

.content-section p:hover {
    color: var(--text-secondary);
}

/* Sentence Animation Styles */
.sentence {
    opacity: 0;
    transform: translateY(20px);
    transition: all 0.8s cubic-bezier(0.4, 0, 0.2, 1);
    display: inline;
    margin-right: 5px;
}

.sentence.visible {
    opacity: 1;
    transform: translateY(0);
}

.sentence.animate-in {
    animation: sentenceSlideIn 0.8s cubic-bezier(0.4, 0, 0.2, 1) forwards;
}

@keyframes sentenceSlideIn {
    from {
        opacity: 0;
        transform: translateY(30px) scale(0.95);
    }
    to {
        opacity: 1;
        transform: translateY(0) scale(1);
    }
}

.text-animation-progress {
    position: fixed;
    bottom: 20px;
    right: 20px;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    color: var(--white);
    padding: 12px 20px;
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-medium);
    font-size: 0.9rem;
    font-weight: 600;
    z-index: 1000;
    display: none;
    max-width: 300px;
}

.skip-animation-btn {
    background: linear-gradient(135deg, var(--light-teal) 0%, var(--accent-teal) 100%);
    color: var(--primary-teal);
    border: none;
    padding: 8px 15px;
    border-radius: var(--border-radius);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    margin-top: 10px;
    transition: var(--transition);
    width: 100%;
}

.skip-animation-btn:hover {
    background: linear-gradient(135deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    color: var(--white);
    transform: translateY(-1px);
}

/* Quiz Container */
.quiz-container {
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    padding: 50px;
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-heavy);
    max-width: 800px;
    margin: 50px auto;
    text-align: center;
    display: none;
    border: 1px solid var(--border-light);
}

.quiz-container h2 {
    font-size: 2.4rem;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 40px;
    font-weight: 700;
}

.question-text {
    font-size: 1.4rem;
    margin-bottom: 30px;
    color: var(--text-primary);
    font-weight: 500;
    line-height: 1.6;
}

.options-container {
    display: flex;
    flex-direction: column;
    gap: 16px;
    margin-bottom: 40px;
}

.option-button {
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    border: 2px solid var(--border-light);
    padding: 18px 25px;
    border-radius: var(--border-radius);
    font-size: 1.1rem;
    cursor: pointer;
    transition: var(--transition);
    text-align: left;
    font-weight: 500;
    position: relative;
    overflow: hidden;
}

.option-button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(102, 204, 204, 0.1), transparent);
    transition: left 0.5s;
}

.option-button:hover::before {
    left: 100%;
}

.option-button:hover {
    background: linear-gradient(135deg, var(--light-teal) 0%, var(--accent-teal) 100%);
    border-color: var(--secondary-teal);
    transform: translateY(-2px);
    box-shadow: var(--shadow-light);
    color: var(--white);
}

.option-button.correct {
    background: linear-gradient(135deg, #d4edda 0%, #c3e6cb 100%);
    border-color: #28a745;
    color: #155724;
    font-weight: 600;
    box-shadow: var(--shadow-light);
}

.option-button.wrong {
    background: linear-gradient(135deg, #f8d7da 0%, #f5c6cb 100%);
    border-color: #dc3545;
    color: #721c24;
    font-weight: 600;
    box-shadow: var(--shadow-light);
}

.feedback {
    margin-top: 25px;
    font-size: 1.2rem;
    font-weight: 600;
    min-height: 30px;
    padding: 15px;
    border-radius: var(--border-radius);
    transition: var(--transition);
}

.feedback.correct-feedback {
    color: #28a745;
    background: linear-gradient(135deg, #d4edda 0%, #c3e6cb 100%);
}

.feedback.wrong-feedback {
    color: #dc3545;
    background: linear-gradient(135deg, #f8d7da 0%, #f5c6cb 100%);
}

.quiz-navigation-buttons {
    display: flex;
    justify-content: center;
    gap: 25px;
    margin-top: 40px;
}

.quiz-navigation-buttons button {
    padding: 15px 30px;
    font-size: 1.2rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    color: var(--white);
    font-weight: 600;
    box-shadow: var(--shadow-light);
    position: relative;
    overflow: hidden;
}

.quiz-navigation-buttons button::before {
    content: '';
    position: absolute;
    top: 0;
    left: -100%;
    width: 100%;
    height: 100%;
    background: linear-gradient(90deg, transparent, rgba(255,255,255,0.2), transparent);
    transition: left 0.5s;
}

.quiz-navigation-buttons button:hover::before {
    left: 100%;
}

.quiz-navigation-buttons button:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-medium);
}

.quiz-navigation-buttons button:disabled {
    background: linear-gradient(135deg, #ccc 0%, #bbb 100%);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

#quiz-result {
    font-size: 1.6rem;
    font-weight: 700;
    margin-top: 50px;
    color: var(--primary-teal);
    padding: 25px;
    background: linear-gradient(135deg, var(--light-teal) 0%, var(--accent-teal) 100%);
    border-radius: var(--border-radius);
    box-shadow: var(--shadow-light);
}

/* Identification Page */
.identification-page {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    padding: 20px;
    box-sizing: border-box;
}

.identification-content {
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    padding: 60px;
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-heavy);
    max-width: 650px;
    width: 100%;
    text-align: left;
    border: 1px solid var(--border-light);
}

.identification-page h1 {
    font-family: 'Roboto', sans-serif;
    font-size: 1.5rem;
    color: var(--text-primary);
    margin-bottom: 50px;
    font-weight: 700;
    text-align: center;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
}

.identification-page .input-group label {
    color: var(--text-primary);
    font-weight: 600;
    font-size: 1.1rem;
}

.identification-page .id-input-group {
    display: flex;
    gap: 20px;
    align-items: flex-end;
}

.identification-page .id-input-group input {
    flex-grow: 1;
    padding: 18px;
    border: 2px solid var(--border-light);
    border-radius: var(--border-radius);
    font-size: 1.2rem;
    box-sizing: border-box;
    transition: var(--transition);
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    font-weight: 500;
}

.identification-page .id-input-group input:focus {
    outline: none;
    border-color: var(--secondary-teal);
    box-shadow: 0 0 0 4px rgba(102, 204, 204, 0.2);
    background: var(--white);
}

.identification-page .open-course-button {
    padding: 18px 30px;
    background: linear-gradient(135deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    color: var(--white);
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.2rem;
    font-weight: 600;
    cursor: pointer;
    transition: var(--transition);
    white-space: nowrap;
    box-shadow: var(--shadow-light);
}

.identification-page .open-course-button:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
}

/* Landing Page */
.landing-page {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    text-align: center;
    min-height: 100vh;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 30%, var(--light-teal) 100%);
    padding: 20px;
    box-sizing: border-box;
}

.landing-page-content {
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    padding: 60px;
    border-radius: var(--border-radius-large);
    box-shadow: var(--shadow-heavy);
    max-width: 650px;
    width: 100%;
    border: 1px solid var(--border-light);
}

.landing-page h1 {
    font-family: 'Roboto', sans-serif;
    font-size: 2rem;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 50%, var(--light-teal) 100%);
    -webkit-background-clip: text;
    background-clip: text;
    -webkit-text-fill-color: transparent;
    margin-bottom: 25px;
    font-weight: 700;
    line-height: 1.2;
}

.landing-page p {
    font-size: 1.3rem;
    color: var(--text-secondary);
    margin-bottom: 35px;
    font-weight: 500;
}

.input-group {
    margin-bottom: 25px;
    text-align: left;
}

.input-group label {
    display: block;
    margin-bottom: 10px;
    font-weight: 600;
    color: var(--text-primary);
    font-size: 1.1rem;
}

.input-group input {
    width: 100%;
    padding: 18px;
    border: 2px solid var(--border-light);
    border-radius: var(--border-radius);
    font-size: 1.2rem;
    box-sizing: border-box;
    transition: var(--transition);
    background: linear-gradient(135deg, var(--white) 0%, var(--background-light) 100%);
    font-weight: 500;
}

.input-group input:focus {
    outline: none;
    border-color: var(--secondary-teal);
    box-shadow: 0 0 0 4px rgba(102, 204, 204, 0.2);
    background: var(--white);
}

.start-button {
    width: 100%;
    padding: 20px;
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    color: var(--white);
    border: none;
    border-radius: var(--border-radius);
    font-size: 1.6rem;
    font-weight: 700;
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-medium);
    text-transform: uppercase;
    letter-spacing: 1px;
}

.start-button:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-heavy);
    background: linear-gradient(135deg, var(--dark-teal) 0%, var(--primary-teal) 100%);
}

/* Course Navigation */
.course-navigation {
    display: flex;
    justify-content: flex-end;
    gap: 20px;
    margin-top: 50px;
}

.course-navigation button {
    padding: 15px 30px;
    font-size: 1.2rem;
    border: none;
    border-radius: var(--border-radius);
    cursor: pointer;
    transition: var(--transition);
    background: linear-gradient(135deg, var(--secondary-teal) 0%, var(--light-teal) 100%);
    color: var(--white);
    font-weight: 600;
    min-width: 140px;
    box-shadow: var(--shadow-light);
}

.course-navigation button:hover {
    background: linear-gradient(135deg, var(--primary-teal) 0%, var(--secondary-teal) 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-medium);
}

.course-navigation button:disabled {
    background: linear-gradient(135deg, #ccc 0%, #bbb 100%);
    cursor: not-allowed;
    transform: none;
    box-shadow: none;
}

#timeConstraintMessage {
    color: #dc3545;
    font-weight: 600;
    margin-top: 15px;
    text-align: right;
    display: none;
    padding: 10px;
    background: linear-gradient(135deg, #f8d7da 0%, #f5c6cb 100%);
    border-radius: var(--border-radius);
    border: 1px solid #dc3545;
}

/* Responsive Design */
@media (max-width: 900px) {
    body {
        zoom: 1; /* Normale Größe auf Mobile */
    }

    .container {
        flex-direction: column;
        margin: 0;
        border-radius: 0;
        box-shadow: none;
        height: auto;
        min-height: 100vh;
    }

    .sidebar {
        width: 100%;
        border-right: none;
        border-bottom: 1px solid var(--border-light);
        padding: 20px;
        box-shadow: 0 2px 10px rgba(44, 102, 102, 0.1);
    }

    .sidebar h2 {
        text-align: center;
        margin-bottom: 20px;
        font-size: 1.4rem;
    }

    .nav-list {
        display: flex;
        flex-wrap: wrap;
        justify-content: center;
        gap: 10px;
        max-height: 250px;
        overflow-y: auto;
    }

    .nav-list li {
        margin-bottom: 0;
        flex-shrink: 0;
    }

    .nav-list a {
        padding: 10px 15px;
        font-size: 0.9rem;
    }

    .main-content {
        padding: 30px 20px;
        max-width: 100%;
    }

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

    .content-section h2 {
        font-size: 1.6rem;
    }

    .landing-page h1 {
        font-size: 2.4rem;
    }

    .landing-page p {
        font-size: 1.1rem;
    }

    .input-group input, .start-button {
        font-size: 1.1rem;
        padding: 15px;
    }

    .quiz-container {
        padding: 30px 20px;
        margin: 20px;
    }

    .question-text {
        font-size: 1.2rem;
    }

    .option-button {
        font-size: 1rem;
        padding: 15px 20px;
    }

    .quiz-navigation-buttons button {
        padding: 12px 25px;
        font-size: 1.1rem;
    }

    #quiz-result {
        font-size: 1.3rem;
    }

    .identification-page h1 {
        font-size: 2rem;
    }

    .identification-page .open-course-button {
        font-size: 1.1rem;
        padding: 15px 25px;
    }

    .identification-page .id-input-group {
        flex-direction: column;
        align-items: stretch;
        gap: 15px;
    }

    .identification-content, .landing-page-content {
        padding: 40px 30px;
    }
}

@media (max-width: 480px) {
    .main-content {
        padding: 20px 15px;
    }

    .identification-content, .landing-page-content {
        padding: 30px 20px;
    }

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

    .landing-page h1 {
        font-size: 2rem;
    }
}