/* ===========================================
   Claude Code Course — Стили
   =========================================== */

/* --- CSS Variables --- */
:root {
    --color-bg: #FAF9F5;
    --color-sidebar: #F0EEE6;
    --color-text: #141413;
    --color-text-secondary: #615F5B;
    --color-text-muted: #5A697C;
    --color-code: #7F0A0C;
    --color-code-bg: #F0EEE6;
    --color-border: rgba(0, 0, 0, 0.08);
    --color-border-dark: #D5D5D5;
    --color-white: #FFFFFF;
    --color-btn-dark: #2C2B25;
    --color-heading: #2A2A2A;
    --color-completed: #141413;
    --color-pending: #5A697C;

    --font-main: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --font-code: 'JetBrains Mono', 'Monaco', monospace;

    --sidebar-width: 420px;
    --footer-height: 50px;
    --content-padding: 72px;
    --border-radius: 8px;
    --border-radius-sm: 12px;
}

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-main);
    font-size: 1rem;
    line-height: 1.6;
    color: var(--color-text);
    background: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

a {
    color: inherit;
    text-decoration: none;
}

ul,
ol {
    list-style-position: outside;
    padding-left: 0;
}

img {
    max-width: 100%;
    height: auto;
    display: block;
}

/* --- Layout --- */
.app {
    display: grid;
    grid-template-columns: var(--sidebar-width) 1fr;
    grid-template-rows: 1fr auto;
    min-height: 100vh;
}

/* --- Sidebar --- */
.sidebar {
    grid-row: 1 / -1;
    background: var(--color-sidebar);
    overflow-y: auto;
    padding: 36px 16px 16px;
}

.sidebar-header {
    margin-bottom: 8px;
}

.course-title {
    font-size: 26px;
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: -0.65px;
    color: var(--color-text);
    margin-bottom: 6px;
}

.course-overview {
    font-size: 18px;
    font-weight: 400;
    color: var(--color-text-secondary);
    letter-spacing: -0.3px;
    display: block;
    padding: 8px 0;
}

.course-overview:hover {
    color: var(--color-text);
}

.sidebar-search {
    padding: 4px 0 8px;
}

.sidebar-search-input {
    width: 100%;
    padding: 8px 10px;
    border-radius: 8px;
    border: 1px solid var(--color-border);
    background: rgba(255, 255, 255, 0.6);
    font-size: 14px;
    color: var(--color-text);
    outline: none;
}

.sidebar-search-input::placeholder {
    color: var(--color-text-muted);
}

.sidebar-search-input:focus {
    border-color: var(--color-border-dark);
    background: var(--color-white);
}

/* --- Lessons Navigation --- */
.lessons-nav {
    margin-top: 12px;
}

.nav-section {
    margin-bottom: 12px;
}

.nav-section-title {
    font-family: 'Roboto', var(--font-main);
    font-size: 18px;
    font-weight: 500;
    color: var(--color-heading);
    padding: 30px 16px 8px;
}

.nav-lesson {
    display: flex;
    align-items: center;
    gap: 9px;
    padding: 10px 16px;
    font-size: 18px;
    font-weight: 400;
    color: var(--color-text);
    letter-spacing: -0.27px;
    line-height: 25px;
    border-radius: 6px;
    transition: background 0.15s ease;
}

@media (max-width: 600px) {
    .nav-lesson {
        align-items: flex-start;
    }
}

.nav-lesson:hover {
    background: rgba(0, 0, 0, 0.04);
}

.nav-lesson.active {
    font-weight: 500;
    background: rgba(0, 0, 0, 0.06);
}

.nav-lesson-icon {
    width: 15px;
    height: 18px;
    flex-shrink: 0;
}

@media (max-width: 600px) {
    .nav-lesson-icon {
        margin-top: 4px;
    }
}

.nav-lesson-icon.completed {
    color: var(--color-completed);
    margin-bottom: 7px;
}

@media (max-width: 600px) {
    .nav-lesson-icon.completed {
        margin-bottom: 0;
        position: relative;
        top:-4px;
    }
}

.nav-lesson-icon.pending {
    color: var(--color-pending);
}

/* Отдельные страницы (без секции) */
.nav-standalone {
    margin-bottom: 8px;
}

/* --- Main Content --- */
.content {
    background: var(--color-bg);
    overflow-y: auto;
}

.content-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 36px var(--content-padding) 0;
    border-bottom: 1px solid var(--color-border);
    padding-bottom: 12px;
    margin-bottom: 16px;
}

.lesson-title {
    font-size: 24px;
    font-weight: 600;
    line-height: 1.4;
    letter-spacing: -0.6px;
    color: var(--color-heading);
}

.header-actions {
    display: flex;
    gap: 8px;
}

@media (max-width: 600px) {
    .header-actions {
       display: none;
    }
}

.btn-secondary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 7px 16px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: rgba(255, 255, 255, 0.3);
    border: 1px solid var(--color-border);
    border-radius: var(--border-radius-sm);
    transition: all 0.15s ease;
}

.btn-secondary:hover {
    background: rgba(255, 255, 255, 0.5);
    color: var(--color-text);
}

.btn-primary {
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 8px 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-white);
    background: var(--color-btn-dark);
    border-radius: var(--border-radius);
    transition: all 0.15s ease;
}

.btn-primary:hover {
    background: #1a1914;
}

/* --- Lesson Content --- */
.lesson-content {
    padding: 0 var(--content-padding);
}

.lesson-content > *:not(.video-container):not(.support-banner) {
    max-width: 900px;
}

.video-container {
    max-width: 100%;
}

/* Video Player */
.video-container {
    background: #000;
    border-radius: var(--border-radius);
    overflow: hidden;
    margin-bottom: 32px;
    aspect-ratio: 16/9;
}

.video-container iframe,
.video-container video {
    width: 100%;
    height: 100%;
    border: none;
}

.video-placeholder {
    width: 100%;
    height: 100%;
    display: flex;
    align-items: center;
    justify-content: center;
    color: #666;
    font-size: 14px;
}

/* Text Content */
.lesson-text {
    font-size: 19.8px;
    line-height: 31px;
    letter-spacing: -0.1px;
    color: var(--color-text);
    margin-bottom: 24px;
}

.lesson-text p {
    margin-bottom: 16px;
}

.lesson-text p:last-child {
    margin-bottom: 0;
}

/* Headings */
.lesson-content h2 {
    font-size: 32px;
    font-weight: 500;
    line-height: 37px;
    letter-spacing: -0.88px;
    color: var(--color-text);
    margin: 48px 0 24px;
}

.lesson-content h3 {
    font-size: 24px;
    font-weight: 500;
    line-height: 32px;
    letter-spacing: -0.6px;
    color: var(--color-text);
    margin: 36px 0 16px;
}

/* Inline Code */
.inline-code {
    font-family: var(--font-code);
    font-size: 18px;
    font-weight: 700;
    color: var(--color-code);
    letter-spacing: -0.1px;
}

/* Code Blocks */
.code-block {
    background: var(--color-code-bg);
    border-radius: var(--border-radius);
    padding: 24px;
    margin: 16px 0 24px;
    overflow-x: auto;
    position: relative;
}

.code-block pre {
    margin: 0;
    font-family: var(--font-code);
    font-size: 16px;
    line-height: 24px;
    color: var(--color-text);
    white-space: pre-wrap;
    word-break: break-word;
}

.code-block .copy-btn {
    position: absolute;
    top: 12px;
    right: 12px;
    padding: 6px 12px;
    font-size: 12px;
    font-weight: 500;
    color: var(--color-text-secondary);
    background: var(--color-white);
    border: 1px solid var(--color-border);
    border-radius: 6px;
    cursor: pointer;
    opacity: 0;
    transition: opacity 0.15s ease;
}

.code-block:hover .copy-btn {
    opacity: 1;
}

.code-block .copy-btn:hover {
    background: var(--color-bg);
}

.code-block .copy-btn.copied {
    color: #16a34a;
}

/* Lists */
.lesson-content ul,
.lesson-content ol {
    margin: 16px 0 24px 38px;
}

.lesson-content li {
    font-size: 19.8px;
    line-height: 28px;
    letter-spacing: -0.1px;
    color: var(--color-text);
    margin-bottom: 4px;
}

.lesson-content ul li {
    list-style-type: disc;
}

.lesson-content ol li {
    list-style-type: decimal;
}

/* Images */
.lesson-image {
    margin: 24px 0;
    border-radius: var(--border-radius);
    overflow: hidden;
}

.lesson-image img {
    width: 100%;
}

.lesson-image figcaption {
    font-size: 14px;
    color: var(--color-text-secondary);
    text-align: center;
    padding: 8px 0;
}

/* --- Footer Navigation --- */
.footer {
    grid-column: 2;
    display: flex;
    gap: 12px;
    padding: 24px var(--content-padding) 48px;
    background: transparent;
    border: none;
    justify-content: flex-start;
}

.nav-prev,
.nav-next {
    width: 200px;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 14px 20px;
    font-size: 15px;
    font-weight: 500;
    letter-spacing: -0.3px;
    border-radius: var(--border-radius);
    transition: all 0.15s ease;
}

.nav-prev {
    color: var(--color-text);
    background: transparent;
    border: 1px solid var(--color-border-dark);
}

.nav-prev:hover {
    background: rgba(0, 0, 0, 0.03);
}

.nav-next {
    color: #fff;
    background: var(--color-btn-dark);
}

.nav-next:hover {
    background: #1a1914;
}

.nav-prev.hidden,
.nav-next.hidden {
    display: none;
}

/* Когда только одна кнопка видна, занимает всю ширину */
.footer:has(.nav-prev.hidden) .nav-next,
.footer:has(.nav-next.hidden) .nav-prev {
    flex: 1;
}

/* Скрываем мобильные элементы на десктопе */
.mobile-menu-btn,
.sidebar-overlay,
.sidebar-close {
    display: none;
}

/* --- Responsive --- */
@media (max-width: 1200px) {
    :root {
        --sidebar-width: 360px;
        --content-padding: 48px;
    }
}

@media (max-width: 992px) {
    .app {
        grid-template-columns: 1fr;
    }

    .sidebar {
        position: fixed;
        left: -100%;
        top: 0;
        bottom: 0;
        width: 320px;
        z-index: 1000;
        transition: left 0.3s ease;
        box-shadow: 2px 0 12px rgba(0, 0, 0, 0.15);
        display: flex;
        flex-direction: column;
    }

    .sidebar.open {
        left: 0;
    }

    /* Контент sidebar скроллится */
    .sidebar .lessons-nav {
        flex: 1;
        overflow-y: auto;
        padding-bottom: 70px;
    }

    /* Кнопка закрытия sidebar - внизу на всю ширину */
    .sidebar-close {
        width: 200px;
        display: flex;
        align-items: center;
        justify-content: center;
        gap: 8px;
        position: absolute;
        bottom: 10px;
        border-radius: 16px;
        left: 10px;
        right: 0;
        height: 56px;
        background: var(--color-btn-dark);
        border: none;
        cursor: pointer;
        color: var(--color-white);
        font-size: 15px;
        font-weight: 500;
        transition: all 0.15s ease;
    }

    .sidebar-close:hover {
        background: #1a1914;
    }

    /* Overlay для мобильного меню */
    .sidebar-overlay {
        display: none;
        position: fixed;
        top: 0;
        left: 0;
        right: 0;
        bottom: 0;
        background: rgba(0, 0, 0, 0.5);
        z-index: 999;
        opacity: 0;
        transition: opacity 0.3s ease;
    }

    .sidebar-overlay.active {
        display: block;
        opacity: 1;
    }

    /* Кнопка открытия меню - фиксированная в левом нижнем углу */
    .mobile-menu-btn {
        display: flex;
        align-items: center;
        justify-content: center;
        position: fixed;
        bottom: 16px;
        left: 16px;
        width: 48px;
        height: 48px;
        background: var(--color-sidebar);
        border: 1px solid var(--color-border-dark);
        border-radius: 12px;
        cursor: pointer;
        color: var(--color-text);
        z-index: 998;
        box-shadow: 0 2px 8px rgba(0, 0, 0, 0.1);
        transition: all 0.15s ease;
    }

    .mobile-menu-btn:hover {
        background: var(--color-bg);
        box-shadow: 0 4px 12px rgba(0, 0, 0, 0.15);
    }

    .mobile-menu-btn:active {
        transform: scale(0.95);
    }

    .content-header {
        padding-left: 16px;
        padding-right: 16px;
        gap: 12px;
    }

    .lesson-title {
        font-size: 20px;
    }

    .lesson-content {
        padding: 0 16px;
    }

    .footer {
        grid-column: 1;
        padding: 24px 16px 32px;
        flex-wrap: wrap;
    }

    .nav-prev,
    .nav-next {
        width: 100%;
    }
}

@media (max-width: 600px) {
    :root {
        --content-padding: 16px;
    }

    .lesson-text {
        font-size: 17px;
        line-height: 27px;
    }

    .lesson-content h2 {
        font-size: 26px;
        line-height: 32px;
    }

    .code-block {
        padding: 16px;
        margin-left: -16px;
        margin-right: -16px;
        border-radius: 0;
    }

    .code-block pre {
        font-size: 14px;
    }
}

/* --- Utilities --- */
.hidden {
    display: none !important;
}

.sr-only {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0, 0, 0, 0);
    white-space: nowrap;
    border: 0;
}

/* ===========================================
   Quiz Styles
   =========================================== */

.quiz-container {
    max-width: 800px;
}

.quiz-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    margin-bottom: 40px;
}

.quiz-title {
    font-size: 18px;
    font-weight: 400;
    color: var(--color-text-secondary);
}

.quiz-progress {
    font-size: 16px;
    color: var(--color-text-secondary);
}

.quiz-question {
    display: none;
}

.quiz-question:first-child {
    display: block;
}

.question-text {
    font-size: 24px;
    font-weight: 400;
    line-height: 1.4;
    color: var(--color-text);
    margin-bottom: 32px;
    font-family: Georgia, 'Times New Roman', serif;
}

.quiz-options {
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.quiz-option {
    display: flex;
    align-items: flex-start;
    gap: 12px;
    padding: 16px 20px;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 8px;
    cursor: pointer;
    transition: all 0.15s ease;
}

.quiz-option:hover {
    background: var(--color-white);
    border-color: var(--color-border-dark);
}

.quiz-option input[type="radio"] {
    width: 20px;
    height: 20px;
    margin-top: 2px;
    flex-shrink: 0;
    accent-color: var(--color-btn-dark);
}

.quiz-option .option-text {
    font-size: 17px;
    line-height: 1.5;
    color: var(--color-text);
}

.quiz-option:has(input:checked) {
    background: var(--color-white);
    border-color: var(--color-btn-dark);
}

/* Quiz Navigation */
.quiz-navigation {
    display: flex;
    justify-content: center;
    gap: 12px;
    margin-top: 40px;
}

.quiz-btn {
    padding: 12px 24px;
    font-size: 15px;
    font-weight: 500;
    border-radius: 8px;
    border: none;
    cursor: pointer;
    transition: all 0.15s ease;
}

.quiz-btn:disabled {
    opacity: 0.5;
    cursor: not-allowed;
}

.quiz-btn-primary {
    background: #4169E1;
    color: var(--color-white);
}

.quiz-btn-primary:hover:not(:disabled) {
    background: #3457c7;
}

.quiz-btn-secondary {
    background: var(--color-white);
    color: var(--color-text);
    border: 1px solid var(--color-border-dark);
}

.quiz-btn-secondary:hover:not(:disabled) {
    background: var(--color-bg);
}

/* Quiz Results */
.quiz-results {
    text-align: center;
    padding: 60px 20px;
}

.results-icon {
    margin-bottom: 24px;
}

.results-title {
    font-size: 36px;
    font-weight: 400;
    font-family: Georgia, 'Times New Roman', serif;
    margin-bottom: 32px;
    color: var(--color-text);
}

.results-score {
    font-size: 20px;
    margin-bottom: 16px;
}

.results-score span {
    font-size: 24px;
}

.results-threshold {
    font-size: 16px;
    color: var(--color-text-secondary);
    margin-bottom: 40px;
}

.results-actions {
    display: flex;
    justify-content: center;
    gap: 12px;
    flex-wrap: wrap;
}

/* ===========================================
   Support Banner
   =========================================== */

.support-banner {
    position: relative;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 24px;
    padding: 24px 32px;
    margin-bottom: 32px;
    background: linear-gradient(135deg, #F0EEE6 0%, #E8E6DC 100%);
    border: 1px solid rgba(0, 0, 0, 0.06);
    border-radius: 16px;
    overflow: hidden;

    /* Анимация появления */
    animation: bannerSlideIn 0.6s ease-out;
}

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

/* Декоративный градиент слева */
.support-banner::before {
    content: '';
    position: absolute;
    left: 0;
    top: 0;
    bottom: 0;
    width: 4px;
    background: linear-gradient(180deg, #D4A574 0%, #B8956E 100%);
}

.support-banner-content {
    display: flex;
    align-items: center;
    gap: 18px;
    flex: 1;
}

.support-banner-icon {
    flex-shrink: 0;
    width: 44px;
    height: 44px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, #D4A574 0%, #C49B6A 100%);
    border-radius: 10px;
    color: white;

    /* Пульсирующая анимация */
    animation: iconPulse 2s ease-in-out infinite;
}

@keyframes iconPulse {
    0%, 100% {
        transform: scale(1);
        box-shadow: 0 4px 12px rgba(212, 165, 116, 0.3);
    }
    50% {
        transform: scale(1.05);
        box-shadow: 0 6px 20px rgba(212, 165, 116, 0.5);
    }
}

.support-banner-icon svg {
    width: 24px;
    height: 24px;
}

.support-banner-text {
    flex: 1;
}

.support-banner-title {
    font-size: 16px;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 2px;
    letter-spacing: -0.2px;
}

.support-banner-description {
    font-size: 15px;
    color: #4A4945;
    line-height: 1.5;
}

.support-banner-btn {
    flex-shrink: 0;
    display: inline-flex;
    align-items: center;
    gap: 8px;
    padding: 10px 20px;
    font-size: 14px;
    font-weight: 500;
    color: var(--color-white);
    background: linear-gradient(135deg, #D4A574 0%, #B8956E 100%);
    border: none;
    border-radius: 8px;
    cursor: pointer;
    text-decoration: none;
    transition: all 0.25s ease;
    box-shadow: 0 2px 8px rgba(212, 165, 116, 0.3);
}

.support-banner-btn:hover {
    transform: translateY(-2px);
    box-shadow: 0 4px 16px rgba(212, 165, 116, 0.4);
    background: linear-gradient(135deg, #C49B6A 0%, #A88560 100%);
}

.support-banner-btn:active {
    transform: translateY(0);
    box-shadow: 0 2px 8px rgba(212, 165, 116, 0.3);
}

.support-banner-btn svg {
    width: 16px;
    height: 16px;
}

/* Кнопка закрытия */
.support-banner-close {
    position: absolute;
    top: 8px;
    right: 8px;
    width: 24px;
    height: 24px;
    display: flex;
    align-items: center;
    justify-content: center;
    background: transparent;
    border: none;
    border-radius: 4px;
    cursor: pointer;
    color: var(--color-text-secondary);
    opacity: 0;
    transition: all 0.2s ease;
}

.support-banner:hover .support-banner-close {
    opacity: 0.6;
}

.support-banner-close:hover {
    opacity: 1 !important;
    background: rgba(0, 0, 0, 0.05);
}

/* Адаптивность */
@media (max-width: 768px) {
    .support-banner {
        flex-direction: column;
        align-items: flex-start;
        text-align: left;
        padding: 16px;
        gap: 12px;
    }

    .support-banner-content {
        flex-direction: row;
        align-items: flex-start;
        gap: 12px;
    }

    .support-banner-icon {
        width: 36px;
        height: 36px;
        margin-top: 2px;
    }

    .support-banner-icon svg {
        width: 18px;
        height: 18px;
    }

    .support-banner-title {
        font-size: 14px;
    }

    .support-banner-description {
        font-size: 13px;
    }

    .support-banner-btn {
        width: auto;
        padding: 8px 16px;
        font-size: 13px;
        margin-left: 48px;
    }
}

/* Quiz Answers */
.quiz-answers {
    padding: 20px 0;
}

.quiz-answers h2 {
    font-size: 28px;
    font-weight: 500;
    margin-bottom: 32px;
}

.answers-list {
    display: flex;
    flex-direction: column;
    gap: 24px;
    margin-bottom: 40px;
}

.answer-item {
    padding: 20px;
    border-radius: 8px;
    background: var(--color-bg);
    border-left: 4px solid;
}

.answer-item.correct {
    border-left-color: #16a34a;
}

.answer-item.incorrect {
    border-left-color: #dc2626;
}

.answer-question {
    font-size: 17px;
    font-weight: 500;
    margin-bottom: 12px;
    line-height: 1.4;
}

.answer-number {
    color: var(--color-text-secondary);
    margin-right: 4px;
}

.answer-status {
    margin-right: 8px;
}

.answer-item.correct .answer-status {
    color: #16a34a;
}

.answer-item.incorrect .answer-status {
    color: #dc2626;
}

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

.correct-answer {
    margin-bottom: 8px;
}

.correct-answer strong {
    color: #16a34a;
}

.user-answer strong {
    color: #dc2626;
}

/* Responsive Quiz */
@media (max-width: 600px) {
    .question-text {
        font-size: 20px;
    }

    .quiz-option {
        padding: 14px 16px;
    }

    .quiz-option .option-text {
        font-size: 15px;
    }

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

    .quiz-navigation {
        flex-direction: column;
    }

    .quiz-btn {
        width: 100%;
    }
}