/* === Reset & Base === */
*, *::before, *::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    --vk-blue: #0077FF;
    --vk-blue-dark: #0059CC;
    --vk-blue-light: #E3F0FF;
    --text: #1A1A2E;
    --text-secondary: #5A5A7A;
    --bg: #FFFFFF;
    --bg-light: #F7F9FC;
    --bg-card: #FFFFFF;
    --border: #E8EBF0;
    --success: #07bc0c;
    --warning: #FFB800;
    --radius: 12px;
    --radius-lg: 20px;
    --shadow: 0 2px 12px rgba(0,0,0,0.06);
    --shadow-lg: 0 8px 32px rgba(0,0,0,0.1);
    --transition: 0.3s ease;
}

html {
    scroll-behavior: smooth;
    -webkit-text-size-adjust: 100%;
}

body {
    font-family: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    color: var(--text);
    background: var(--bg);
    line-height: 1.6;
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
}

.container {
    max-width: 1120px;
    margin: 0 auto;
    padding: 0 20px;
}

/* === Buttons === */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 12px 24px;
    border: none;
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
    text-decoration: none;
    line-height: 1.4;
}

.btn--primary {
    background: var(--vk-blue);
    color: #fff;
}

.btn--primary:hover {
    background: var(--vk-blue-dark);
    transform: translateY(-1px);
    box-shadow: 0 4px 16px rgba(0,119,255,0.3);
}

.btn--secondary {
    background: var(--bg-light);
    color: var(--text);
}

.btn--secondary:hover {
    background: var(--border);
}

.btn--large {
    padding: 16px 32px;
    font-size: 17px;
    border-radius: 14px;
}

/* === Section Common === */
.section__title {
    font-size: 32px;
    font-weight: 800;
    text-align: center;
    margin-bottom: 8px;
    letter-spacing: -0.5px;
}

.section__subtitle {
    text-align: center;
    color: var(--text-secondary);
    font-size: 17px;
    margin-bottom: 48px;
}

/* === Hero === */
.hero {
    padding: 80px 0 60px;
    background: linear-gradient(180deg, var(--vk-blue-light) 0%, var(--bg) 100%);
    text-align: center;
}

.hero__badge {
    display: inline-block;
    background: rgba(0,119,255,0.1);
    color: var(--vk-blue);
    padding: 6px 16px;
    border-radius: 50px;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 24px;
}

.hero__title {
    font-size: 40px;
    font-weight: 800;
    line-height: 1.2;
    max-width: 800px;
    margin: 0 auto 20px;
    letter-spacing: -0.5px;
}

.hero__highlight {
    color: var(--vk-blue);
    position: relative;
}

.hero__highlight::after {
    content: '';
    position: absolute;
    bottom: 2px;
    left: 0;
    right: 0;
    height: 8px;
    background: rgba(0,119,255,0.15);
    border-radius: 4px;
    z-index: -1;
}

.hero__subtitle {
    font-size: 18px;
    color: var(--text-secondary);
    max-width: 640px;
    margin: 0 auto 32px;
    line-height: 1.6;
}

.hero__stats {
    display: flex;
    justify-content: center;
    gap: 48px;
    margin-top: 48px;
}

.hero__stat {
    display: flex;
    flex-direction: column;
}

.hero__stat-number {
    font-size: 28px;
    font-weight: 800;
    color: var(--vk-blue);
}

.hero__stat-label {
    font-size: 14px;
    color: var(--text-secondary);
}

/* === Steps === */
.steps {
    padding: 80px 0;
    background: var(--bg);
}

.steps__grid {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: 24px;
}

.step {
    text-align: center;
    padding: 32px 20px;
    border-radius: var(--radius-lg);
    background: var(--bg-light);
    position: relative;
    transition: all var(--transition);
}

.step:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.step__number {
    position: absolute;
    top: 16px;
    left: 16px;
    width: 28px;
    height: 28px;
    background: var(--vk-blue);
    color: #fff;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 13px;
    font-weight: 700;
}

.step__icon {
    width: 56px;
    height: 56px;
    background: var(--vk-blue-light);
    border-radius: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin: 0 auto 16px;
    color: var(--vk-blue);
}

.step__title {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
}

.step__desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* === Quiz === */
.quiz {
    padding: 80px 0;
    background: var(--bg-light);
}

.quiz__wrapper {
    max-width: 640px;
    margin: 0 auto;
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 40px;
    box-shadow: var(--shadow-lg);
}

.quiz__progress {
    height: 6px;
    background: var(--border);
    border-radius: 3px;
    overflow: hidden;
    margin-bottom: 8px;
}

.quiz__progress-bar {
    height: 100%;
    background: linear-gradient(90deg, var(--vk-blue), #4DA3FF);
    border-radius: 3px;
    width: 14.28%;
    transition: width 0.4s ease;
}

.quiz__step-info {
    font-size: 13px;
    color: var(--text-secondary);
    margin-bottom: 32px;
    text-align: center;
}

.quiz__slide {
    display: none;
    animation: fadeIn 0.3s ease;
}

.quiz__slide.active {
    display: block;
}

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

.quiz__question {
    font-size: 22px;
    font-weight: 700;
    margin-bottom: 6px;
}

.quiz__hint {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 24px;
}

/* Form elements */
.form-group {
    margin-bottom: 20px;
}

.form-label {
    display: block;
    font-size: 14px;
    font-weight: 600;
    margin-bottom: 6px;
}

.form-optional {
    color: var(--text-secondary);
    font-weight: 400;
}

.form-input,
.form-select,
.form-textarea {
    width: 100%;
    padding: 12px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-family: inherit;
    font-size: 15px;
    color: var(--text);
    background: var(--bg);
    transition: border-color var(--transition);
    outline: none;
}

.form-input:focus,
.form-select:focus,
.form-textarea:focus {
    border-color: var(--vk-blue);
}

.form-input.error,
.form-select.error,
.form-textarea.error {
    border-color: #e74c3c;
}

.form-textarea {
    resize: vertical;
    min-height: 80px;
}

.form-select {
    appearance: none;
    background-image: url("data:image/svg+xml,%3Csvg width='12' height='8' viewBox='0 0 12 8' fill='none' xmlns='http://www.w3.org/2000/svg'%3E%3Cpath d='M1 1.5L6 6.5L11 1.5' stroke='%235A5A7A' stroke-width='2' stroke-linecap='round' stroke-linejoin='round'/%3E%3C/svg%3E");
    background-repeat: no-repeat;
    background-position: right 16px center;
    padding-right: 40px;
}

/* Checkbox cards */
.checkbox-grid {
    display: grid;
    grid-template-columns: repeat(2, 1fr);
    gap: 12px;
}

.checkbox-card {
    cursor: pointer;
}

.checkbox-card input {
    display: none;
}

.checkbox-card__inner {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 14px 16px;
    border: 2px solid var(--border);
    border-radius: var(--radius);
    font-size: 14px;
    font-weight: 500;
    transition: all var(--transition);
}

.checkbox-card__icon {
    color: var(--text-secondary);
    flex-shrink: 0;
    transition: color var(--transition);
}

.checkbox-card input:checked + .checkbox-card__inner {
    border-color: var(--vk-blue);
    background: var(--vk-blue-light);
}

.checkbox-card input:checked + .checkbox-card__inner .checkbox-card__icon {
    color: var(--vk-blue);
}

.checkbox-card__inner:hover {
    border-color: var(--vk-blue);
}

/* Agreement checkbox */
.checkbox-agree {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    cursor: pointer;
    font-size: 14px;
    color: var(--text-secondary);
}

.checkbox-agree input {
    margin-top: 3px;
    accent-color: var(--vk-blue);
}

/* Quiz Navigation */
.quiz__nav {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-top: 32px;
    gap: 12px;
}

/* === Result === */
.result {
    padding: 80px 0;
    background: var(--bg-light);
}

.result__wrapper {
    text-align: center;
    max-width: 800px;
    margin: 0 auto;
}

.result__icon {
    margin-bottom: 16px;
}

.result__title {
    font-size: 32px;
    font-weight: 800;
    margin-bottom: 12px;
}

.result__desc {
    font-size: 17px;
    color: var(--text-secondary);
    margin-bottom: 40px;
}

.result__cards {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 20px;
    margin-bottom: 40px;
    text-align: left;
}

.result__card {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 24px;
    box-shadow: var(--shadow);
}

.result__card--highlight {
    border: 2px solid var(--vk-blue);
    background: var(--vk-blue-light);
}

.result__card-icon {
    color: var(--vk-blue);
    margin-bottom: 12px;
}

.result__card h3 {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 12px;
}

.result__card ul {
    list-style: none;
    padding: 0;
}

.result__card li {
    font-size: 14px;
    color: var(--text-secondary);
    padding: 4px 0 4px 20px;
    position: relative;
}

.result__card li::before {
    content: '';
    position: absolute;
    left: 0;
    top: 11px;
    width: 8px;
    height: 8px;
    background: var(--success);
    border-radius: 50%;
}

.result__card p {
    font-size: 14px;
    color: var(--text-secondary);
}

.result__actions {
    text-align: center;
}

.result__note {
    margin-top: 16px;
    font-size: 14px;
    color: var(--text-secondary);
}

/* === Advantages === */
.advantages {
    padding: 80px 0;
    background: var(--bg);
}

.advantages__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.advantage {
    padding: 28px;
    border-radius: var(--radius-lg);
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.advantage:hover {
    border-color: var(--vk-blue);
    box-shadow: var(--shadow);
    transform: translateY(-2px);
}

.advantage__icon {
    width: 48px;
    height: 48px;
    background: var(--vk-blue-light);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: var(--vk-blue);
    margin-bottom: 16px;
}

.advantage__title {
    font-size: 16px;
    font-weight: 700;
    margin-bottom: 8px;
}

.advantage__desc {
    font-size: 14px;
    color: var(--text-secondary);
    line-height: 1.5;
}

/* === Cases === */
.cases {
    padding: 80px 0;
    background: var(--bg-light);
}

.cases__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.case {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 28px;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.case:hover {
    transform: translateY(-4px);
    box-shadow: var(--shadow-lg);
}

.case__badge {
    display: inline-block;
    background: var(--vk-blue-light);
    color: var(--vk-blue);
    padding: 4px 12px;
    border-radius: 50px;
    font-size: 12px;
    font-weight: 600;
    margin-bottom: 12px;
}

.case__title {
    font-size: 18px;
    font-weight: 700;
    margin-bottom: 8px;
}

.case__desc {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 20px;
    line-height: 1.5;
}

.case__results {
    display: flex;
    gap: 16px;
}

.case__result {
    flex: 1;
    text-align: center;
    padding: 12px 0;
    background: var(--bg-light);
    border-radius: var(--radius);
}

.case__result-value {
    display: block;
    font-size: 18px;
    font-weight: 800;
    color: var(--vk-blue);
}

.case__result-label {
    font-size: 11px;
    color: var(--text-secondary);
}

/* === FAQ === */
.faq {
    padding: 80px 0;
    background: var(--bg);
}

.faq__list {
    max-width: 720px;
    margin: 0 auto;
}

.faq__item {
    border-bottom: 1px solid var(--border);
}

.faq__question {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 20px 0;
    background: none;
    border: none;
    font-family: inherit;
    font-size: 16px;
    font-weight: 600;
    color: var(--text);
    cursor: pointer;
    text-align: left;
    gap: 16px;
}

.faq__arrow {
    flex-shrink: 0;
    transition: transform var(--transition);
    color: var(--text-secondary);
}

.faq__item.active .faq__arrow {
    transform: rotate(180deg);
}

.faq__answer {
    max-height: 0;
    overflow: hidden;
    transition: max-height 0.3s ease, padding 0.3s ease;
}

.faq__item.active .faq__answer {
    max-height: 200px;
    padding-bottom: 20px;
}

.faq__answer p {
    font-size: 15px;
    color: var(--text-secondary);
    line-height: 1.6;
}

/* === Reviews === */
.reviews {
    padding: 80px 0;
    background: var(--bg-light);
}

.reviews__grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 24px;
}

.review {
    background: var(--bg-card);
    border-radius: var(--radius-lg);
    padding: 28px;
    box-shadow: var(--shadow);
}

.review__stars {
    display: flex;
    gap: 2px;
    margin-bottom: 16px;
}

.review__text {
    font-size: 15px;
    color: var(--text);
    line-height: 1.6;
    margin-bottom: 20px;
    font-style: italic;
}

.review__author {
    display: flex;
    align-items: center;
    gap: 12px;
}

.review__avatar {
    width: 40px;
    height: 40px;
    background: var(--vk-blue-light);
    color: var(--vk-blue);
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 14px;
    font-weight: 700;
}

.review__name {
    font-size: 14px;
    font-weight: 600;
}

.review__role {
    font-size: 13px;
    color: var(--text-secondary);
}

/* === CTA Bottom === */
.cta-bottom {
    padding: 80px 0;
    background: linear-gradient(135deg, var(--vk-blue) 0%, var(--vk-blue-dark) 100%);
    text-align: center;
}

.cta-bottom__title {
    font-size: 32px;
    font-weight: 800;
    color: #fff;
    margin-bottom: 12px;
}

.cta-bottom__desc {
    font-size: 17px;
    color: rgba(255,255,255,0.8);
    margin-bottom: 32px;
}

.cta-bottom .btn--primary {
    background: #fff;
    color: var(--vk-blue);
}

.cta-bottom .btn--primary:hover {
    background: #f0f0f0;
    box-shadow: 0 4px 16px rgba(0,0,0,0.2);
}

/* === Footer === */
.footer {
    padding: 24px 0;
    background: var(--text);
    text-align: center;
}

.footer p {
    font-size: 14px;
    color: rgba(255,255,255,0.5);
}

/* === Loading overlay === */
.loading-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(255,255,255,0.95);
    z-index: 1000;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 20px;
}

.loading-overlay.active {
    display: flex;
}

.spinner {
    width: 48px;
    height: 48px;
    border: 4px solid var(--border);
    border-top-color: var(--vk-blue);
    border-radius: 50%;
    animation: spin 0.8s linear infinite;
}

@keyframes spin {
    to { transform: rotate(360deg); }
}

.loading-text {
    font-size: 17px;
    font-weight: 600;
    color: var(--text);
}

.loading-subtext {
    font-size: 14px;
    color: var(--text-secondary);
}

/* === Mobile Responsive === */
@media (max-width: 1024px) {
    .steps__grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .advantages__grid,
    .cases__grid,
    .reviews__grid,
    .result__cards {
        grid-template-columns: repeat(2, 1fr);
    }
}

@media (max-width: 768px) {
    .hero {
        padding: 60px 0 40px;
    }

    .hero__title {
        font-size: 28px;
    }

    .hero__subtitle {
        font-size: 16px;
    }

    .hero__stats {
        gap: 24px;
    }

    .hero__stat-number {
        font-size: 22px;
    }

    .section__title {
        font-size: 24px;
    }

    .section__subtitle {
        font-size: 15px;
        margin-bottom: 32px;
    }

    .steps__grid,
    .advantages__grid,
    .cases__grid,
    .reviews__grid,
    .result__cards {
        grid-template-columns: 1fr;
    }

    .quiz__wrapper {
        padding: 24px;
    }

    .quiz__question {
        font-size: 18px;
    }

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

    .quiz__nav {
        flex-wrap: wrap;
    }

    #submitBtn {
        width: 100%;
    }

    .case__results {
        flex-wrap: wrap;
    }

    .case__result {
        min-width: calc(50% - 8px);
    }

    .cta-bottom__title {
        font-size: 24px;
    }

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

@media (max-width: 480px) {
    .hero__title {
        font-size: 24px;
    }

    .hero__stats {
        flex-direction: column;
        gap: 16px;
    }
}