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

:root {
    --purple: #e1bee7;
    --purple-hover: #d1a3dd;
    --green: #c8e6c9;
    --dark: #333;
    --light-bg: #f5f5f5;
    --shadow-sm: 0 2px 8px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.12);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.15);
    --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    line-height: 1.7;
    background-color: #c8e6c9;
    color: var(--dark);
    min-height: 100vh;
    font-size: 16px;
}


h1, h2, h3 {
    font-weight: 600;
    line-height: 1.3;
}

h1 { font-size: clamp(1.8rem, 4vw, 2.5rem); }
h2 { font-size: clamp(1.4rem, 3vw, 1.8rem); }
h3 { font-size: clamp(1.1rem, 2.5vw, 1.3rem); }

p {
    font-size: clamp(0.95rem, 2vw, 1.05rem);
}


.main-container {
    max-width: 1400px;
    margin: 0 auto;
    padding: clamp(20px, 5vw, 60px) clamp(15px, 3vw, 40px);
    animation: fadeIn 0.6s ease-out;
}

@keyframes fadeIn {
    from { opacity: 0; transform: translateY(20px); }
    to { opacity: 1; transform: translateY(0); }
}

.student-card {
    background: linear-gradient(135deg, var(--purple) 0%, #ce93d8 100%);
    border-radius: 24px;
    padding: clamp(30px, 5vw, 50px);
    text-align: center;
    margin-bottom: clamp(30px, 5vw, 50px);
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    border: 2px solid rgba(255,255,255,0.3);
}

.student-card:hover {
    transform: translateY(-5px);
    box-shadow: 0 12px 32px rgba(0,0,0,0.18);
}

.student-card h1 {
    margin-bottom: 15px;
    color: var(--dark);
    text-shadow: 0 2px 4px rgba(0,0,0,0.1);
}

.student-card p {
    font-size: clamp(1rem, 2.5vw, 1.15rem);
    margin: 8px 0;
    color: rgba(0,0,0,0.8);
}

.student-card .student-name {
    font-weight: 700;
    margin-top: 20px;
    font-size: clamp(1.1rem, 2.5vw, 1.3rem);
    color: var(--dark);
}


.lab-cards {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(min(100%, 320px), 1fr));
    gap: clamp(20px, 4vw, 35px);
    margin-bottom: clamp(30px, 5vw, 50px);
}

.lab-card {
    background: linear-gradient(135deg, var(--purple) 0%, #ce93d8 100%);
    border-radius: 20px;
    padding: clamp(40px, 8vw, 70px) clamp(25px, 5vw, 40px);
    text-align: center;
    text-decoration: none;
    color: var(--dark);
    transition: var(--transition);
    box-shadow: var(--shadow-md);
    border: 2px solid rgba(255,255,255,0.2);
    position: relative;
    overflow: hidden;
}

.lab-card::before {
    content: '';
    position: absolute;
    top: -50%;
    left: -50%;
    width: 200%;
    height: 200%;
    background: radial-gradient(circle, rgba(255,255,255,0.1) 0%, transparent 70%);
    opacity: 0;
    transition: var(--transition);
}

.lab-card:hover::before {
    opacity: 1;
}

.lab-card:hover {
    transform: translateY(-8px) scale(1.02);
    box-shadow: var(--shadow-lg);
    border-color: rgba(255,255,255,0.4);
}

.lab-card h2 {
    font-weight: 600;
    position: relative;
    z-index: 1;
}


.lab-page {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    animation: fadeIn 0.5s ease-out;
}

.lab-header {
    background: linear-gradient(135deg, var(--dark) 0%, #424242 100%);
    color: white;
    padding: clamp(15px, 3vw, 25px) clamp(20px, 4vw, 50px);
    display: flex;
    justify-content: space-between;
    align-items: center;
    box-shadow: var(--shadow-md);
    gap: 15px;
    flex-wrap: wrap;
}

.lab-header h1 {
    flex: 1 1 auto;
    text-align: center;
    min-width: 200px;
    text-shadow: 0 2px 4px rgba(0,0,0,0.2);
}

.back-btn, .nav-link, .nav-btn {
    background: linear-gradient(135deg, var(--purple) 0%, #ce93d8 100%);
    color: var(--dark);
    padding: clamp(8px, 2vw, 12px) clamp(15px, 3vw, 25px);
    border-radius: 12px;
    text-decoration: none;
    font-weight: 600;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    font-size: clamp(0.85rem, 2vw, 0.95rem);
    white-space: nowrap;
    border: 2px solid transparent;
}

.back-btn:hover, .nav-link:hover, .nav-btn:hover {
    background: linear-gradient(135deg, var(--purple-hover) 0%, #ba68c8 100%);
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    border-color: rgba(255,255,255,0.3);
}

.back-btn:active, .nav-link:active, .nav-btn:active {
    transform: translateY(0);
}

.nav-link.disabled {
    opacity: 0.4;
    pointer-events: none;
}


.lab2-header {
    justify-content: space-between;
}

.lab2-header .nav-btn {
    flex: 0 1 auto;
}


.lab-content {
    flex: 1;
    max-width: 1400px;
    margin: clamp(30px, 5vw, 50px) auto;
    padding: 0 clamp(15px, 3vw, 40px);
    width: 100%;
}

.content-card {
    background: linear-gradient(135deg, var(--purple) 0%, #ce93d8 100%);
    border-radius: 24px;
    padding: clamp(30px, 5vw, 50px);
    margin-bottom: clamp(25px, 4vw, 40px);
    box-shadow: var(--shadow-lg);
    transition: var(--transition);
    border: 2px solid rgba(255,255,255,0.2);
}

.content-card:hover {
    box-shadow: 0 12px 36px rgba(0,0,0,0.15);
}

.content-card h2 {
    margin-bottom: 25px;
    color: var(--dark);
    padding-bottom: 15px;
    border-bottom: 3px solid rgba(0,0,0,0.1);
}

.content-card p {
    margin-bottom: 18px;
    line-height: 1.8;
    color: rgba(0,0,0,0.85);
}


.logos {
    display: flex;
    flex-direction: column;
    gap: clamp(40px, 8vw, 70px);
    margin-top: clamp(40px, 6vw, 70px);
}

.logo {
    max-width: min(350px, 90%);
    width: 100%;
    height: auto;
    object-fit: contain;
    filter: drop-shadow(0 4px 8px rgba(0,0,0,0.15));
    transition: var(--transition);
}

.logo:hover {
    transform: scale(1.05);
    filter: drop-shadow(0 6px 12px rgba(0,0,0,0.2));
}

.logo:nth-child(1) { align-self: flex-end; }
.logo:nth-child(2) { align-self: flex-start; }
.logo:nth-child(3) { align-self: flex-end; }


.lab2-main-card {
    background: linear-gradient(135deg, var(--purple) 0%, #ce93d8 100%);
}

.lab2-main-card h2 {
    text-align: center;
    margin-bottom: clamp(30px, 5vw, 50px);
}

.lab2-section {
    margin-bottom: clamp(35px, 6vw, 50px);
    padding: clamp(20px, 4vw, 30px);
    background: rgba(255,255,255,0.15);
    border-radius: 16px;
    transition: var(--transition);
}

.lab2-section:hover {
    background: rgba(255,255,255,0.25);
    transform: translateX(5px);
}

.lab2-section:last-child {
    margin-bottom: 0;
}

.lab2-section h3 {
    margin-bottom: 20px;
    color: var(--dark);
}

.formula-placeholder {
    background: linear-gradient(135deg, var(--green) 0%, #a5d6a7 100%);
    border-radius: 16px;
    padding: clamp(50px, 10vw, 80px);
    text-align: center;
    font-size: clamp(2.5rem, 8vw, 4rem);
    margin-top: 15px;
    box-shadow: inset 0 2px 8px rgba(0,0,0,0.1);
    color: var(--dark);
    font-weight: 300;
    transition: var(--transition);
}

.formula-placeholder:hover {
    transform: scale(1.02);
    box-shadow: inset 0 3px 12px rgba(0,0,0,0.15);
}


.input-group {
    margin-bottom: 20px;
}

.input-group label {
    display: block;
    margin-bottom: 8px;
    font-weight: 600;
    color: var(--dark);
    font-size: clamp(0.9rem, 2vw, 1rem);
}

.input-group input {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid rgba(0,0,0,0.1);
    border-radius: 10px;
    font-size: clamp(0.95rem, 2vw, 1rem);
    background-color: rgba(255,255,255,0.5);
    transition: var(--transition);
    font-family: 'Courier New', monospace;
}

.input-group input:focus {
    outline: none;
    border-color: var(--purple-hover);
    background-color: rgba(255,255,255,0.8);
    box-shadow: 0 0 0 3px rgba(225, 190, 231, 0.3);
}

.input-row {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(150px, 1fr));
    gap: 15px;
    margin-bottom: 20px;
}

.calculate-btn {
    width: 100%;
    padding: 14px 28px;
    background: linear-gradient(135deg, var(--green) 0%, #a5d6a7 100%);
    border: none;
    border-radius: 12px;
    font-size: clamp(1rem, 2.5vw, 1.1rem);
    font-weight: 600;
    color: var(--dark);
    cursor: pointer;
    transition: var(--transition);
    box-shadow: var(--shadow-sm);
    margin-top: 10px;
}

.calculate-btn:hover {
    transform: translateY(-2px);
    box-shadow: var(--shadow-md);
    background: linear-gradient(135deg, #a5d6a7 0%, #81c784 100%);
}

.calculate-btn:active {
    transform: translateY(0);
}

.result-box {
    margin-top: 25px;
    padding: 20px;
    background: rgba(255,255,255,0.3);
    border-radius: 12px;
    border: 2px solid rgba(0,0,0,0.1);
    transition: var(--transition);
}

.result-box.success {
    border-color: #4CAF50;
    background-color: #f1f8f4;
}

.result-box.error {
    border-color: #f44336;
    background-color: #ffebee;
}

.result-box.error .result-value {
    color: #d32f2f;
    font-size: 0.9em;
}

.result-label {
    font-weight: 600;
    margin-bottom: 8px;
    color: var(--dark);
    font-size: clamp(0.95rem, 2vw, 1.05rem);
}

.result-value {
    font-size: clamp(1.2rem, 3vw, 1.5rem);
    font-weight: 700;
    color: var(--dark);
    font-family: 'Courier New', monospace;
    margin: 0;
}

/* ЛР2 - інтеграл з межами */
.integral-container {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 15px;
    margin: 30px 0;
    flex-wrap: wrap;
}

.integral-symbol {
    display: flex;
    flex-direction: column;
    align-items: center;
    position: relative;
}

.integral-s {
    font-size: clamp(4rem, 10vw, 6rem);
    font-weight: 300;
    color: var(--dark);
    line-height: 1;
    font-family: 'Times New Roman', serif;
    user-select: none;
}

.limit-input {
    width: 80px;
    padding: 8px 10px;
    border: 2px solid rgba(0,0,0,0.15);
    border-radius: 8px;
    font-size: clamp(0.9rem, 2vw, 1rem);
    background-color: rgba(255,255,255,0.6);
    transition: var(--transition);
    font-family: 'Courier New', monospace;
    text-align: center;
    font-weight: 600;
}

.limit-input.upper {
    margin-bottom: 5px;
}

.limit-input.lower {
    margin-top: 5px;
}

.limit-input:focus {
    outline: none;
    border-color: var(--purple-hover);
    background-color: rgba(255,255,255,0.9);
    box-shadow: 0 0 0 3px rgba(225, 190, 231, 0.3);
}

.function-input-wrapper {
    display: flex;
    align-items: center;
    gap: 10px;
}

.function-input {
    width: clamp(150px, 30vw, 250px);
    padding: 12px 16px;
    border: 2px solid rgba(0,0,0,0.15);
    border-radius: 10px;
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    background-color: rgba(255,255,255,0.6);
    transition: var(--transition);
    font-family: 'Courier New', monospace;
    font-weight: 600;
}

.function-input:focus {
    outline: none;
    border-color: var(--purple-hover);
    background-color: rgba(255,255,255,0.9);
    box-shadow: 0 0 0 3px rgba(225, 190, 231, 0.3);
}

.dx-label {
    font-size: clamp(1rem, 2.5vw, 1.2rem);
    font-style: italic;
    font-weight: 600;
    color: var(--dark);
    font-family: 'Times New Roman', serif;
}


footer {
    background: rgba(255,255,255,0.9);
    backdrop-filter: blur(10px);
    text-align: center;
    padding: clamp(20px, 4vw, 30px);
    margin-top: auto;
    font-size: clamp(0.85rem, 2vw, 0.95rem);
    color: #666;
    box-shadow: 0 -2px 10px rgba(0,0,0,0.05);
}

footer p {
    margin: 0;
}


/* API Section Styles */
.api-section {
    margin: 20px 0;
    padding: 20px;
    background: #f5f5f5;
    border-radius: 8px;
}

.form-group {
    margin-bottom: 15px;
}

.form-group label {
    display: block;
    margin-bottom: 5px;
    font-weight: bold;
    color: #333;
}

.form-group input {
    width: 100%;
    padding: 10px;
    border: 1px solid #ddd;
    border-radius: 4px;
    font-size: 14px;
    box-sizing: border-box;
}

.form-group small {
    display: block;
    margin-top: 5px;
    color: #666;
    font-size: 12px;
}

.primary-btn, .secondary-btn {
    padding: 10px 20px;
    margin-right: 10px;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    font-size: 14px;
    transition: all 0.3s;
}

.primary-btn {
    background: #4CAF50;
    color: white;
}

.primary-btn:hover {
    background: #45a049;
}

.primary-btn:disabled {
    background: #cccccc;
    cursor: not-allowed;
}

.secondary-btn {
    background: #f44336;
    color: white;
}

.secondary-btn:hover {
    background: #da190b;
}

/* Status Messages */
.status-message {
    padding: 15px;
    margin: 15px 0;
    border-radius: 4px;
    display: none;
}

.status-message.info {
    background: #2196F3;
    color: white;
}

.status-message.success {
    background: #4CAF50;
    color: white;
}

.status-message.error {
    background: #f44336;
    color: white;
}

/* Results Container */
.results-container {
    margin-top: 20px;
}

.listings-grid {
    display: grid;
    grid-template-columns: repeat(auto-fill, minmax(280px, 1fr));
    gap: 20px;
    margin-top: 20px;
}

.listing-card {
    background: white;
    border: 1px solid #ddd;
    border-radius: 8px;
    padding: 15px;
    box-shadow: 0 2px 4px rgba(0,0,0,0.1);
    transition: transform 0.2s;
}

.listing-card:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 8px rgba(0,0,0,0.15);
}

.listing-card h4 {
    margin: 0 0 10px 0;
    color: #333;
    font-size: 16px;
}

.listing-card .wear {
    color: #666;
    font-size: 14px;
    margin: 5px 0;
}

.listing-card .price {
    color: #4CAF50;
    font-weight: bold;
    font-size: 18px;
    margin: 10px 0;
}

.listing-card .float {
    color: #2196F3;
    font-size: 14px;
    margin: 5px 0;
}

.inspect-link {
    display: inline-block;
    margin-top: 10px;
    padding: 8px 15px;
    background: #2196F3;
    color: white;
    text-decoration: none;
    border-radius: 4px;
    font-size: 13px;
    transition: background 0.3s;
}

.inspect-link:hover {
    background: #0b7dda;
}


@media (max-width: 1024px) {
    .logo:nth-child(1),
    .logo:nth-child(2),
    .logo:nth-child(3) {
        align-self: center;
    }
}

@media (max-width: 768px) {
    body {
        font-size: 15px;
    }
    
    .lab-header {
        flex-direction: column;
        text-align: center;
        padding: 20px 15px;
    }
    
    .lab-header h1 {
        order: -1;
        margin-bottom: 15px;
    }
    
    .back-btn, .nav-link {
        width: 100%;
        max-width: 300px;
    }
    
    .lab2-header {
        flex-direction: column;
        gap: 12px;
    }
    
    .lab2-header .nav-btn {
        width: 100%;
        max-width: 350px;
        text-align: center;
    }
    
    .student-card {
        padding: 30px 20px;
    }
    
    .lab-cards {
        grid-template-columns: 1fr;
        gap: 20px;
    }
    
    .lab-card {
        padding: 50px 25px;
    }
    
    .input-row {
        grid-template-columns: 1fr;
    }
    
    .integral-container {
        flex-direction: column;
        gap: 20px;
    }
    
    .function-input {
        width: 100%;
        max-width: 250px;
    }
}

@media (max-width: 480px) {
    .main-container {
        padding: 15px 10px;
    }
    
    .content-card {
        padding: 25px 20px;
    }
    
    .lab2-section {
        padding: 20px 15px;
    }
    
    .formula-placeholder {
        padding: 40px 20px;
    }
}


@media (prefers-reduced-motion: reduce) {
    * {
        animation-duration: 0.01ms !important;
        animation-iteration-count: 1 !important;
        transition-duration: 0.01ms !important;
    }
}

@media (prefers-color-scheme: dark) {
    :root {
        --dark: #1a1a1a;
    }
    
    body {
        background-color: #c8e6c9;
    }
    
    .content-card p {
        color: rgba(0,0,0,0.9);
    }
}


html {
    scroll-behavior: smooth;
}


a:focus-visible, button:focus-visible {
    outline: 3px solid var(--purple);
    outline-offset: 3px;
}