/* ===== ESP32 Drone - Shared Styles ===== */
/* Clean, educational theme for STEM education */

:root {
    --primary: #3B82F6;
    --primary-dark: #2563EB;
    --primary-light: #DBEAFE;
    --secondary: #10B981;
    --secondary-dark: #059669;
    --accent: #F59E0B;
    --bg-light: #F8FAFC;
    --bg-white: #FFFFFF;
    --bg-code: #1E293B;
    --text-dark: #1E293B;
    --text-medium: #475569;
    --text-light: #94A3B8;
    --border: #E2E8F0;
    --border-light: #F1F5F9;
    --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
    --shadow: 0 4px 6px -1px rgba(0,0,0,0.1), 0 2px 4px -1px rgba(0,0,0,0.06);
    --shadow-lg: 0 20px 25px -5px rgba(0,0,0,0.1), 0 10px 10px -5px rgba(0,0,0,0.04);
    --radius: 12px;
    --radius-sm: 8px;
    --sidebar-width: 260px;
    --header-height: 64px;
}

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

body {
    font-family: 'Inter', 'Noto Sans SC', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg-light);
    color: var(--text-dark);
    line-height: 1.7;
    font-size: 15px;
}

a { color: var(--primary); text-decoration: none; transition: color 0.2s; }
a:hover { color: var(--primary-dark); }

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

/* ===== Header ===== */
.site-header {
    position: fixed;
    top: 0;
    width: 100%;
    height: var(--header-height);
    background: var(--bg-white);
    border-bottom: 1px solid var(--border);
    z-index: 100;
    display: flex;
    align-items: center;
}

.header-inner {
    max-width: 1400px;
    width: 100%;
    margin: 0 auto;
    padding: 0 2rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
}

.logo {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    font-weight: 700;
    font-size: 1.25rem;
    color: var(--text-dark);
}

.logo-icon {
    width: 34px;
    height: 34px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    border-radius: 8px;
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 0.9rem;
}

.logo span { color: var(--primary); }

.nav-links {
    display: flex;
    gap: 1.5rem;
    align-items: center;
    list-style: none;
}

.nav-links a {
    color: var(--text-medium);
    font-weight: 500;
    font-size: 0.9rem;
    padding: 0.4rem 0;
    border-bottom: 2px solid transparent;
    transition: all 0.2s;
}

.nav-links a:hover,
.nav-links a.active {
    color: var(--primary);
    border-bottom-color: var(--primary);
}

.lang-switch {
    display: flex;
    gap: 0.25rem;
    background: var(--bg-light);
    padding: 3px;
    border-radius: var(--radius-sm);
}

.lang-switch a {
    padding: 0.35rem 0.75rem;
    border-radius: 6px;
    font-size: 0.8rem;
    font-weight: 600;
    color: var(--text-medium);
    transition: all 0.2s;
}

.lang-switch a.active {
    background: var(--bg-white);
    color: var(--primary);
    box-shadow: var(--shadow-sm);
}

.mobile-menu-btn {
    display: none;
    background: none;
    border: none;
    font-size: 1.5rem;
    cursor: pointer;
    color: var(--text-dark);
}

/* ===== Layout with Sidebar ===== */
.page-wrapper {
    margin-top: var(--header-height);
    display: flex;
    min-height: calc(100vh - var(--header-height));
}

/* Sidebar */
.sidebar {
    width: var(--sidebar-width);
    background: var(--bg-white);
    border-right: 1px solid var(--border);
    padding: 1.5rem 0;
    position: fixed;
    top: var(--header-height);
    left: 0;
    bottom: 0;
    overflow-y: auto;
    z-index: 50;
}

.sidebar-section {
    margin-bottom: 1.5rem;
}

.sidebar-title {
    padding: 0 1.5rem;
    font-size: 0.7rem;
    font-weight: 700;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-light);
    margin-bottom: 0.5rem;
}

.sidebar-nav {
    list-style: none;
}

.sidebar-nav li a {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    padding: 0.5rem 1.5rem;
    color: var(--text-medium);
    font-size: 0.875rem;
    transition: all 0.2s;
    border-left: 3px solid transparent;
}

.sidebar-nav li a:hover {
    background: var(--bg-light);
    color: var(--primary);
}

.sidebar-nav li a.active {
    background: var(--primary-light);
    color: var(--primary);
    border-left-color: var(--primary);
    font-weight: 600;
}

.sidebar-nav li a .nav-badge {
    margin-left: auto;
    background: var(--primary-light);
    color: var(--primary);
    padding: 0.1rem 0.5rem;
    border-radius: 10px;
    font-size: 0.7rem;
    font-weight: 600;
}

.sidebar-nav .nav-group-title {
    padding: 0.6rem 1.5rem 0.3rem;
    font-size: 0.75rem;
    font-weight: 700;
    color: var(--text-light);
    text-transform: uppercase;
    letter-spacing: 0.05em;
}

/* Main Content */
.main-content {
    flex: 1;
    margin-left: var(--sidebar-width);
    padding: 2rem 3rem;
    max-width: calc(100% - var(--sidebar-width));
}

.content-wrapper {
    max-width: 860px;
}

/* No sidebar layout */
.page-wrapper.no-sidebar .main-content {
    margin-left: 0;
    max-width: 100%;
}

.full-width {
    max-width: 1200px;
    margin: 0 auto;
}

/* ===== Hero Section ===== */
.hero {
    padding: 4rem 0;
    text-align: center;
}

.hero h1 {
    font-size: 2.75rem;
    font-weight: 800;
    margin-bottom: 1rem;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    -webkit-background-clip: text;
    -webkit-text-fill-color: transparent;
    background-clip: text;
}

.hero .subtitle {
    font-size: 1.2rem;
    color: var(--text-medium);
    max-width: 650px;
    margin: 0 auto 2rem;
}

.hero-buttons {
    display: flex;
    gap: 1rem;
    justify-content: center;
    flex-wrap: wrap;
}

/* ===== Buttons ===== */
.btn {
    display: inline-flex;
    align-items: center;
    gap: 0.5rem;
    padding: 0.75rem 1.5rem;
    border-radius: var(--radius-sm);
    font-weight: 600;
    font-size: 0.9rem;
    transition: all 0.2s;
    border: none;
    cursor: pointer;
}

.btn-primary {
    background: var(--primary);
    color: white;
    box-shadow: 0 4px 14px rgba(59,130,246,0.3);
}

.btn-primary:hover {
    background: var(--primary-dark);
    color: white;
    transform: translateY(-1px);
}

.btn-secondary {
    background: var(--bg-white);
    color: var(--text-dark);
    border: 2px solid var(--border);
}

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

.btn-sm {
    padding: 0.5rem 1rem;
    font-size: 0.8rem;
}

.btn-green {
    background: var(--secondary);
    color: white;
}

.btn-green:hover {
    background: var(--secondary-dark);
    color: white;
}

/* ===== Feature Cards ===== */
.features-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.feature-card {
    background: var(--bg-white);
    padding: 1.75rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    transition: all 0.25s;
}

.feature-card:hover {
    transform: translateY(-3px);
    box-shadow: var(--shadow-lg);
    border-color: var(--primary);
}

.feature-icon {
    width: 48px;
    height: 48px;
    background: var(--primary-light);
    border-radius: 12px;
    display: flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 1rem;
    font-size: 1.25rem;
}

.feature-card h3 {
    font-size: 1.05rem;
    margin-bottom: 0.5rem;
}

.feature-card p {
    color: var(--text-medium);
    font-size: 0.875rem;
}

/* ===== Tutorial Content Styles ===== */
.tutorial-header {
    margin-bottom: 2rem;
    padding-bottom: 1.5rem;
    border-bottom: 1px solid var(--border);
}

.tutorial-header .badge {
    display: inline-block;
    padding: 0.25rem 0.75rem;
    border-radius: 20px;
    font-size: 0.75rem;
    font-weight: 600;
    margin-bottom: 0.75rem;
}

.badge-beginner { background: #DCFCE7; color: #166534; }
.badge-intermediate { background: #FEF3C7; color: #92400E; }
.badge-advanced { background: #FEE2E2; color: #991B1B; }

.tutorial-header h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.tutorial-header .meta {
    color: var(--text-medium);
    font-size: 0.9rem;
}

/* Project Cards in Tutorial */
.project-list {
    margin: 2rem 0;
}

.project-card {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    margin-bottom: 1.25rem;
    display: flex;
    gap: 1.25rem;
    transition: all 0.2s;
}

.project-card:hover {
    box-shadow: var(--shadow);
    border-color: var(--primary);
}

.project-number {
    width: 44px;
    height: 44px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.project-info h3 {
    font-size: 1.05rem;
    margin-bottom: 0.35rem;
}

.project-info p {
    color: var(--text-medium);
    font-size: 0.875rem;
}

.difficulty {
    margin-top: 0.4rem;
    font-size: 0.8rem;
}

/* Article Content */
.article h2 {
    font-size: 1.5rem;
    margin: 2.5rem 0 1rem;
    padding-bottom: 0.5rem;
    border-bottom: 2px solid var(--border);
}

.article h3 {
    font-size: 1.2rem;
    margin: 2rem 0 0.75rem;
    color: var(--primary-dark);
}

.article h4 {
    font-size: 1rem;
    margin: 1.5rem 0 0.5rem;
}

.article p {
    margin-bottom: 1rem;
    color: var(--text-medium);
}

.article ul, .article ol {
    margin: 0.5rem 0 1rem 1.5rem;
    color: var(--text-medium);
}

.article li {
    margin-bottom: 0.4rem;
}

.article strong {
    color: var(--text-dark);
}

/* Code Blocks */
.code-block {
    background: var(--bg-code);
    color: #E2E8F0;
    padding: 1.25rem 1.5rem;
    border-radius: var(--radius-sm);
    overflow-x: auto;
    margin: 1rem 0;
    font-family: 'JetBrains Mono', 'Fira Code', 'Consolas', monospace;
    font-size: 0.85rem;
    line-height: 1.6;
    position: relative;
}

.code-block .code-label {
    position: absolute;
    top: 0.5rem;
    right: 0.75rem;
    font-size: 0.7rem;
    color: #64748B;
    font-family: inherit;
}

.code-block .comment { color: #64748B; }
.code-block .keyword { color: #C084FC; }
.code-block .string { color: #4ADE80; }
.code-block .function { color: #60A5FA; }
.code-block .number { color: #FBBF24; }

code {
    background: var(--bg-light);
    padding: 0.15rem 0.4rem;
    border-radius: 4px;
    font-size: 0.85em;
    font-family: 'JetBrains Mono', 'Fira Code', monospace;
    color: var(--primary-dark);
}

/* Info/Warning Boxes */
.info-box {
    padding: 1rem 1.25rem;
    border-radius: var(--radius-sm);
    margin: 1rem 0;
    border-left: 4px solid;
}

.info-box.tip {
    background: #F0FDF4;
    border-color: var(--secondary);
}

.info-box.warning {
    background: #FFFBEB;
    border-color: var(--accent);
}

.info-box.danger {
    background: #FEF2F2;
    border-color: #EF4444;
}

.info-box .box-title {
    font-weight: 700;
    margin-bottom: 0.25rem;
    font-size: 0.85rem;
}

.info-box p {
    font-size: 0.875rem;
    margin-bottom: 0;
}

/* ===== Tables ===== */
.table-wrapper {
    overflow-x: auto;
    margin: 1rem 0;
}

table {
    width: 100%;
    border-collapse: collapse;
    font-size: 0.875rem;
}

th, td {
    padding: 0.75rem 1rem;
    text-align: left;
    border-bottom: 1px solid var(--border);
}

th {
    background: var(--bg-light);
    font-weight: 600;
    color: var(--text-dark);
}

tr:hover td {
    background: var(--border-light);
}

/* ===== Spec Cards ===== */
.specs-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
    gap: 1.25rem;
    margin: 1.5rem 0;
}

.spec-card {
    background: var(--bg-white);
    padding: 1.5rem;
    border-radius: var(--radius);
    border: 1px solid var(--border);
    border-left: 4px solid var(--primary);
}

.spec-card h4 {
    color: var(--primary);
    font-size: 0.75rem;
    text-transform: uppercase;
    letter-spacing: 0.05em;
    margin-bottom: 0.5rem;
}

.spec-card .value {
    font-size: 1.25rem;
    font-weight: 700;
    margin-bottom: 0.25rem;
}

.spec-card .desc {
    color: var(--text-medium);
    font-size: 0.8rem;
}

/* ===== Download Cards ===== */
.download-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
    gap: 1.25rem;
    margin: 1.5rem 0;
}

.download-card {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 1.5rem;
    display: flex;
    gap: 1rem;
    transition: all 0.2s;
}

.download-card:hover {
    box-shadow: var(--shadow);
}

.download-icon {
    width: 48px;
    height: 48px;
    background: linear-gradient(135deg, var(--secondary), #34D399);
    border-radius: var(--radius-sm);
    display: flex;
    align-items: center;
    justify-content: center;
    color: white;
    font-size: 1.2rem;
    flex-shrink: 0;
}

.download-info h4 { margin-bottom: 0.25rem; font-size: 0.95rem; }
.download-info p { color: var(--text-medium); font-size: 0.8rem; margin-bottom: 0.5rem; }
.download-meta { display: flex; gap: 0.75rem; font-size: 0.7rem; color: var(--text-light); }

/* ===== Course Level Cards ===== */
.course-grid {
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
    gap: 1.5rem;
    margin: 2rem 0;
}

.course-card {
    background: var(--bg-white);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    overflow: hidden;
    transition: all 0.25s;
}

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

.course-card .card-header {
    padding: 1.5rem;
    color: white;
}

.course-card .card-header.beginner { background: linear-gradient(135deg, #10B981, #34D399); }
.course-card .card-header.intermediate { background: linear-gradient(135deg, #3B82F6, #60A5FA); }
.course-card .card-header.advanced { background: linear-gradient(135deg, #8B5CF6, #A78BFA); }

.course-card .card-header h3 { font-size: 1.2rem; margin-bottom: 0.25rem; }
.course-card .card-header p { opacity: 0.9; font-size: 0.85rem; }

.course-card .card-body {
    padding: 1.5rem;
}

.course-card .card-body .info-row {
    display: flex;
    justify-content: space-between;
    margin-bottom: 0.5rem;
    font-size: 0.85rem;
    color: var(--text-medium);
}

.course-card .card-body .info-row strong {
    color: var(--text-dark);
}

.course-card .card-footer {
    padding: 0 1.5rem 1.5rem;
}

/* ===== Wiring Diagram ===== */
.wiring-block {
    background: var(--bg-code);
    color: #E2E8F0;
    padding: 1.5rem;
    border-radius: var(--radius-sm);
    margin: 1rem 0;
    font-family: 'JetBrains Mono', monospace;
    font-size: 0.85rem;
    line-height: 1.8;
    white-space: pre;
    overflow-x: auto;
}

/* ===== Footer ===== */
.site-footer {
    background: var(--text-dark);
    color: #CBD5E1;
    padding: 3rem 2rem 1.5rem;
    margin-left: var(--sidebar-width);
}

.page-wrapper.no-sidebar + .site-footer,
.no-sidebar .site-footer {
    margin-left: 0;
}

.footer-inner {
    max-width: 1100px;
    margin: 0 auto;
    display: grid;
    grid-template-columns: repeat(auto-fit, minmax(200px, 1fr));
    gap: 2rem;
    margin-bottom: 2rem;
}

.footer-section h4 {
    color: var(--primary);
    margin-bottom: 0.75rem;
    font-size: 0.9rem;
}

.footer-section a {
    display: block;
    color: #94A3B8;
    font-size: 0.85rem;
    margin-bottom: 0.4rem;
}

.footer-section a:hover { color: white; }

.footer-bottom {
    max-width: 1100px;
    margin: 0 auto;
    padding-top: 1.5rem;
    border-top: 1px solid #334155;
    text-align: center;
    font-size: 0.8rem;
    color: #64748B;
}

/* ===== Responsive ===== */
@media (max-width: 1024px) {
    .sidebar { display: none; }
    .sidebar.open { display: block; }
    .main-content {
        margin-left: 0;
        max-width: 100%;
        padding: 1.5rem;
    }
    .site-footer { margin-left: 0; }
    .mobile-menu-btn { display: block; }
}

@media (max-width: 768px) {
    .hero h1 { font-size: 2rem; }
    .hero .subtitle { font-size: 1rem; }
    .features-grid { grid-template-columns: 1fr; }
    .nav-links { display: none; }
    .project-card { flex-direction: column; }
    .content-wrapper { max-width: 100%; }
    .main-content { padding: 1rem; }
}

/* ===== Language selector page ===== */
.lang-selector {
    min-height: 100vh;
    display: flex;
    align-items: center;
    justify-content: center;
    background: linear-gradient(135deg, var(--bg-light) 0%, #DBEAFE 100%);
}

.lang-selector-card {
    background: var(--bg-white);
    border-radius: 20px;
    padding: 3rem;
    box-shadow: var(--shadow-lg);
    text-align: center;
    max-width: 500px;
}

.lang-selector-card h1 {
    font-size: 2rem;
    margin-bottom: 0.5rem;
}

.lang-selector-card p {
    color: var(--text-medium);
    margin-bottom: 2rem;
}

.lang-options {
    display: flex;
    gap: 1rem;
    justify-content: center;
}

.lang-option {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    padding: 1.5rem 2.5rem;
    background: var(--bg-light);
    border: 2px solid var(--border);
    border-radius: var(--radius);
    transition: all 0.25s;
    font-weight: 600;
    color: var(--text-dark);
}

.lang-option:hover {
    border-color: var(--primary);
    color: var(--primary);
    transform: translateY(-3px);
    box-shadow: var(--shadow);
}

.lang-option .flag {
    font-size: 2rem;
}

/* ===== Pin Map ===== */
.pin-map {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 0.5rem;
    margin: 1rem 0;
}

.pin-row {
    display: flex;
    justify-content: space-between;
    padding: 0.5rem 0.75rem;
    background: var(--bg-light);
    border-radius: 6px;
    font-size: 0.85rem;
}

.pin-row .pin { font-weight: 600; color: var(--primary); font-family: monospace; }
.pin-row .func { color: var(--text-medium); }

/* ===== Step indicator ===== */
.step {
    margin-bottom: 2.5rem;
}

.step-header {
    display: flex;
    align-items: center;
    gap: 1rem;
    margin-bottom: 1rem;
}

.step-num {
    width: 40px;
    height: 40px;
    background: linear-gradient(135deg, var(--primary), var(--secondary));
    color: white;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    flex-shrink: 0;
}

.step-header h3 {
    margin: 0;
    color: var(--text-dark);
}