/* =========================================================
   style.css — التصميم الرئيسي لموقع "تعلم بايثون في 30 يوماً"
   =========================================================
   نظام الألوان مستوحى من علامة Python التجارية:
   - أزرق بايثون العميق كلون أساسي
   - أصفر بايثون كلون تمييز
   - خلفية فاتحة مائلة للأزرق في الوضع النهاري
   - خلفية داكنة زرقاء في الوضع الليلي
   العنصر المميز: "مسار الثعبان" المتعرج الذي يربط الدروس الثلاثين
   ========================================================= */

/* ---------- 1. المتغيرات العامة (Design Tokens) ---------- */
:root {
  /* الألوان الأساسية */
  --python-blue: #306998;
  --python-blue-dark: #1e4a6e;
  --python-blue-light: #4b89b8;
  --python-yellow: #ffd43b;
  --python-yellow-dark: #e6b800;

  /* الوضع النهاري */
  --bg: #f3f7fb;
  --bg-alt: #e9f0f8;
  --surface: rgba(255, 255, 255, 0.65);
  --surface-solid: #ffffff;
  --text-main: #142433;
  --text-muted: #55697b;
  --border-soft: rgba(20, 36, 51, 0.09);
  --shadow-color: rgba(30, 74, 110, 0.15);

  /* تدرجات */
  --gradient-hero: radial-gradient(circle at 20% 20%, rgba(255, 212, 59, 0.25), transparent 45%),
    radial-gradient(circle at 85% 15%, rgba(48, 105, 152, 0.35), transparent 50%),
    linear-gradient(160deg, #eef4fb 0%, #dce9f6 100%);

  /* الطباعة */
  --font-display: "Cairo", "Tajawal", sans-serif;
  --font-body: "Tajawal", "Cairo", sans-serif;

  /* هندسة */
  --radius-sm: 10px;
  --radius-md: 18px;
  --radius-lg: 28px;
  --container: 1180px;
  --transition: 0.35s cubic-bezier(0.22, 1, 0.36, 1);
}

/* الوضع الليلي */
[data-theme="dark"] {
  --bg: #0e1720;
  --bg-alt: #101d29;
  --surface: rgba(23, 37, 51, 0.6);
  --surface-solid: #16232f;
  --text-main: #eaf1f8;
  --text-muted: #93a7b8;
  --border-soft: rgba(255, 255, 255, 0.08);
  --shadow-color: rgba(0, 0, 0, 0.45);
  --gradient-hero: radial-gradient(circle at 20% 20%, rgba(255, 212, 59, 0.1), transparent 45%),
    radial-gradient(circle at 85% 15%, rgba(75, 137, 184, 0.25), transparent 50%),
    linear-gradient(160deg, #0d1620 0%, #0a1119 100%);
}

/* ---------- 2. إعادة الضبط الأساسية ---------- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

html {
  scroll-behavior: smooth;
}

body {
  direction: rtl;
  font-family: var(--font-body);
  background-color: var(--bg);
  color: var(--text-main);
  line-height: 1.75;
  overflow-x: hidden;
  transition: background-color var(--transition), color var(--transition);
}

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

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

ul {
  list-style: none;
}

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

/* احترام تفضيل تقليل الحركة */
@media (prefers-reduced-motion: reduce) {
  *, *::before, *::after {
    animation-duration: 0.001ms !important;
    animation-iteration-count: 1 !important;
    transition-duration: 0.001ms !important;
    scroll-behavior: auto !important;
  }
}

.container {
  width: 100%;
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
}

/* ---------- 3. شريط التنقل العلوي (Glassmorphism) ---------- */
.navbar {
  position: sticky;
  top: 0;
  z-index: 100;
  backdrop-filter: blur(16px) saturate(160%);
  -webkit-backdrop-filter: blur(16px) saturate(160%);
  background: color-mix(in srgb, var(--surface) 92%, transparent);
  border-bottom: 1px solid var(--border-soft);
}

.navbar-inner {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 14px 24px;
  max-width: var(--container);
  margin: 0 auto;
  gap: 16px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.05rem;
}

.brand-logo {
  width: 34px;
  height: 34px;
  flex-shrink: 0;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 6px;
}

.nav-links a {
  padding: 8px 14px;
  border-radius: 999px;
  font-size: 0.92rem;
  font-weight: 600;
  color: var(--text-muted);
  transition: background var(--transition), color var(--transition);
  white-space: nowrap;
}

.nav-links a:hover,
.nav-links a:focus-visible {
  background: var(--bg-alt);
  color: var(--python-blue);
}

.nav-actions {
  display: flex;
  align-items: center;
  gap: 10px;
}

/* زر "تثبيت التطبيق" (PWA Install Button) */
.install-btn {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 10px 16px;
  border-radius: 999px;
  background: linear-gradient(120deg, var(--python-blue), var(--python-blue-light));
  color: #fff;
  font-weight: 700;
  font-size: 0.88rem;
  box-shadow: 0 10px 22px -12px var(--shadow-color);
  transition: transform var(--transition);
  white-space: nowrap;
}

.install-btn:hover {
  transform: translateY(-2px);
}

.install-btn[hidden] {
  display: none;
}

/* شريط إرشادات تثبيت التطبيق على iOS */
.ios-install-banner {
  position: fixed;
  bottom: 16px;
  right: 16px;
  left: 16px;
  z-index: 300;
  max-width: 460px;
  margin: 0 auto;
  background: var(--surface-solid);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  box-shadow: 0 20px 40px -16px var(--shadow-color);
  animation: slideUpBanner 0.4s ease;
}

.ios-install-banner[hidden] {
  display: none;
}

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

.ios-install-content {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 16px 18px;
}

.ios-install-content p {
  flex: 1;
  font-size: 0.88rem;
  color: var(--text-main);
  margin: 0;
}

.ios-install-icon {
  font-size: 1.4rem;
  flex-shrink: 0;
}

.ios-install-content button {
  flex-shrink: 0;
  width: 30px;
  height: 30px;
  border-radius: 50%;
  background: var(--bg-alt);
  font-size: 1rem;
  color: var(--text-muted);
}

.theme-toggle {
  width: 42px;
  height: 42px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-alt);
  border: 1px solid var(--border-soft);
  font-size: 1.2rem;
  transition: transform var(--transition), background var(--transition);
}

.theme-toggle:hover {
  transform: rotate(15deg) scale(1.05);
}

/* شريط التقدم أعلى الصفحة */
.progress-bar-track {
  position: fixed;
  top: 0;
  right: 0;
  left: 0;
  height: 4px;
  background: var(--border-soft);
  z-index: 200;
}

.progress-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--python-blue), var(--python-yellow));
  transition: width 0.5s ease;
}

/* التركيز الظاهر لأغراض إمكانية الوصول */
a:focus-visible,
button:focus-visible,
input:focus-visible {
  outline: 3px solid var(--python-yellow-dark);
  outline-offset: 2px;
}

/* ---------- 4. القسم البطولي (Hero) ---------- */
.hero {
  position: relative;
  padding: 90px 0 70px;
  background: var(--gradient-hero);
  overflow: hidden;
}

.hero-inner {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 24px;
  display: flex;
  flex-direction: column;
  align-items: center;
  text-align: center;
  gap: 26px;
}

.hero-logo {
  width: 132px;
  height: 132px;
  animation: floatLogo 6s ease-in-out infinite;
}

@keyframes floatLogo {
  0%, 100% { transform: translateY(0) rotate(0deg); }
  50% { transform: translateY(-14px) rotate(4deg); }
}

.hero-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  padding: 8px 18px;
  border-radius: 999px;
  background: var(--surface);
  border: 1px solid var(--border-soft);
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--python-blue);
  backdrop-filter: blur(10px);
}

.hero h1 {
  font-family: var(--font-display);
  font-size: clamp(2.1rem, 5vw, 3.4rem);
  font-weight: 800;
  line-height: 1.3;
  max-width: 760px;
}

.hero h1 span {
  color: var(--python-blue);
  position: relative;
}

.hero-subtitle {
  font-size: clamp(1rem, 2vw, 1.2rem);
  color: var(--text-muted);
  max-width: 560px;
}

.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  padding: 16px 38px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 1.05rem;
  font-family: var(--font-display);
  transition: transform var(--transition), box-shadow var(--transition);
}

.btn-primary {
  background: linear-gradient(120deg, var(--python-blue), var(--python-blue-light));
  color: #fff;
  box-shadow: 0 14px 30px -10px var(--shadow-color);
}

.btn-primary:hover {
  transform: translateY(-3px);
  box-shadow: 0 18px 36px -8px var(--shadow-color);
}

.btn-accent {
  background: var(--python-yellow);
  color: #2b2200;
}

.btn-accent:hover {
  transform: translateY(-3px);
}

/* ---------- 5. قسم الإحصائيات ---------- */
.stats {
  margin-top: -46px;
  position: relative;
  z-index: 2;
}

.stats-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 16px;
}

.stat-card {
  background: var(--surface);
  backdrop-filter: blur(14px) saturate(150%);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 26px 18px;
  text-align: center;
  box-shadow: 0 20px 40px -22px var(--shadow-color);
  transition: transform var(--transition);
}

.stat-card:hover {
  transform: translateY(-6px);
}

.stat-number {
  font-family: var(--font-display);
  font-size: 1.9rem;
  font-weight: 800;
  color: var(--python-blue);
  display: block;
}

.stat-label {
  color: var(--text-muted);
  font-size: 0.9rem;
  margin-top: 4px;
}

/* ---------- 6. قسم الدروس والعنوان العام ---------- */
.section {
  padding: 90px 0 40px;
}

.section-head {
  text-align: center;
  max-width: 620px;
  margin: 0 auto 46px;
}

.section-eyebrow {
  color: var(--python-blue);
  font-weight: 700;
  font-size: 0.85rem;
  letter-spacing: 0.06em;
  text-transform: uppercase;
}

.section-head h2 {
  font-family: var(--font-display);
  font-size: clamp(1.7rem, 3.4vw, 2.3rem);
  margin-top: 8px;
  font-weight: 800;
}

.section-head p {
  color: var(--text-muted);
  margin-top: 12px;
}

/* مربع البحث */
.search-box {
  max-width: 460px;
  margin: 0 auto 50px;
  position: relative;
}

.search-box input {
  width: 100%;
  padding: 15px 50px 15px 20px;
  border-radius: 999px;
  border: 1px solid var(--border-soft);
  background: var(--surface-solid);
  color: var(--text-main);
  font-family: var(--font-body);
  font-size: 0.96rem;
  box-shadow: 0 10px 26px -18px var(--shadow-color);
}

.search-box .search-icon {
  position: absolute;
  right: 18px;
  top: 50%;
  transform: translateY(-50%);
  opacity: 0.5;
  pointer-events: none;
}

/* ---------- 7. مسار الدروس المتعرج (Signature Element) ---------- */
.lessons-path {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 28px 20px;
  position: relative;
}

/* تعرّج الصفوف: الصف الزوجي يُعكس بصرياً بإزاحة بسيطة ليعطي إحساس المسار المتموج */
.lessons-path .lesson-card:nth-child(6n+4),
.lessons-path .lesson-card:nth-child(6n+5),
.lessons-path .lesson-card:nth-child(6n+6) {
  margin-top: 34px;
}

.lesson-card {
  position: relative;
  background: var(--surface-solid);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 22px 20px;
  transition: transform var(--transition), box-shadow var(--transition), opacity var(--transition);
  box-shadow: 0 16px 30px -22px var(--shadow-color);
  display: flex;
  flex-direction: column;
  gap: 10px;
  min-height: 100%;
}

.lesson-card:hover {
  transform: translateY(-6px);
  box-shadow: 0 22px 38px -18px var(--shadow-color);
}

.lesson-card .lesson-number {
  width: 40px;
  height: 40px;
  border-radius: 50%;
  background: linear-gradient(135deg, var(--python-blue), var(--python-blue-light));
  color: #fff;
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 0.95rem;
}

.lesson-card .lesson-title {
  font-family: var(--font-display);
  font-weight: 700;
  font-size: 1.05rem;
  line-height: 1.5;
}

.lesson-meta {
  display: flex;
  gap: 10px;
  flex-wrap: wrap;
  font-size: 0.8rem;
  color: var(--text-muted);
}

.lesson-meta span {
  display: inline-flex;
  align-items: center;
  gap: 4px;
  background: var(--bg-alt);
  padding: 4px 10px;
  border-radius: 999px;
}

.lesson-card .lesson-enter {
  margin-top: auto;
  padding-top: 8px;
  font-weight: 700;
  color: var(--python-blue);
  font-size: 0.92rem;
  display: flex;
  align-items: center;
  gap: 6px;
}

.lesson-card .done-check {
  position: absolute;
  top: 16px;
  left: 16px;
  color: #1f9d55;
  font-size: 1.1rem;
}

/* بطاقة الدرس المقفل */
.lesson-card.locked {
  filter: grayscale(0.85);
  opacity: 0.68;
  cursor: not-allowed;
}

.lesson-card.locked:hover {
  transform: none;
  box-shadow: 0 16px 30px -22px var(--shadow-color);
}

.lesson-card.locked .lesson-number {
  background: var(--text-muted);
}

.lesson-card .lock-msg {
  font-size: 0.82rem;
  color: var(--text-muted);
  display: flex;
  align-items: center;
  gap: 6px;
  margin-top: auto;
}

/* ---------- 8. صفحة/نافذة الدرس التفصيلية ---------- */
.lesson-view {
  position: fixed;
  inset: 0;
  background: var(--bg);
  z-index: 500;
  overflow-y: auto;
  transform: translateY(100%);
  opacity: 0;
  transition: transform 0.4s cubic-bezier(0.22, 1, 0.36, 1), opacity 0.4s ease;
}

.lesson-view.open {
  transform: translateY(0);
  opacity: 1;
}

.lesson-view-header {
  position: sticky;
  top: 0;
  z-index: 10;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  padding: 16px 24px;
  background: color-mix(in srgb, var(--surface) 94%, transparent);
  backdrop-filter: blur(14px);
  border-bottom: 1px solid var(--border-soft);
}

.lesson-view-header .back-btn {
  display: flex;
  align-items: center;
  gap: 8px;
  font-weight: 700;
  color: var(--python-blue);
  padding: 10px 16px;
  border-radius: 999px;
  background: var(--bg-alt);
}

.lesson-view-body {
  max-width: 760px;
  margin: 0 auto;
  padding: 40px 24px 100px;
}

.lesson-view-body .lesson-tag {
  display: inline-flex;
  gap: 8px;
  align-items: center;
  color: var(--python-blue);
  font-weight: 700;
  font-size: 0.85rem;
  margin-bottom: 10px;
}

.lesson-view-body h1 {
  font-family: var(--font-display);
  font-size: clamp(1.6rem, 4vw, 2.3rem);
  font-weight: 800;
  margin-bottom: 20px;
}

.lesson-view-body .simple-box {
  background: linear-gradient(120deg, rgba(48,105,152,0.09), rgba(255,212,59,0.12));
  border-right: 4px solid var(--python-blue);
  padding: 18px 20px;
  border-radius: var(--radius-sm);
  margin-bottom: 32px;
  font-weight: 600;
}

.lesson-block {
  margin-bottom: 34px;
}

.lesson-block h3 {
  font-family: var(--font-display);
  font-size: 1.15rem;
  margin-bottom: 12px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.lesson-block p {
  margin-bottom: 12px;
  color: var(--text-main);
}

/* كتلة الكود */
.code-block {
  background: #12202c;
  color: #dbe9f4;
  border-radius: var(--radius-sm);
  padding: 18px 20px;
  overflow-x: auto;
  font-family: "Courier New", monospace;
  font-size: 0.88rem;
  direction: ltr;
  text-align: left;
  margin-bottom: 10px;
  white-space: pre;
  line-height: 1.7;
  border: 1px solid rgba(255,255,255,0.06);
}

[data-theme="dark"] .code-block {
  background: #0a141c;
}

.example-explain {
  color: var(--text-muted);
  font-size: 0.92rem;
  margin-bottom: 22px;
}

/* الصناديق: ملاحظة / نصيحة / أخطاء */
.info-box {
  border-radius: var(--radius-sm);
  padding: 16px 18px;
  margin-bottom: 18px;
  display: flex;
  gap: 12px;
  align-items: flex-start;
  font-size: 0.94rem;
}

.info-box .icon {
  font-size: 1.2rem;
}

.info-box.note {
  background: rgba(48, 105, 152, 0.09);
  border: 1px solid rgba(48, 105, 152, 0.2);
}

.info-box.tip {
  background: rgba(255, 212, 59, 0.14);
  border: 1px solid rgba(230, 184, 0, 0.3);
}

.info-box.mistakes {
  background: rgba(214, 69, 69, 0.08);
  border: 1px solid rgba(214, 69, 69, 0.22);
}

.info-box.mistakes ul {
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.info-box.mistakes li::before {
  content: "✗ ";
  color: #c0392b;
  font-weight: 700;
}

/* التمرين والحل والتحدي */
.exercise-box {
  background: var(--bg-alt);
  border-radius: var(--radius-md);
  padding: 22px;
  margin-bottom: 20px;
}

.solution-toggle {
  background: var(--python-blue);
  color: #fff;
  padding: 10px 20px;
  border-radius: 999px;
  font-weight: 700;
  font-size: 0.9rem;
  margin-top: 12px;
}

.solution-content {
  display: none;
  margin-top: 14px;
}

.solution-content.show {
  display: block;
}

.challenge-box {
  background: linear-gradient(120deg, var(--python-blue), var(--python-blue-dark));
  color: #fff;
  border-radius: var(--radius-md);
  padding: 22px;
  margin-bottom: 20px;
}

.challenge-box h3 {
  color: #fff;
}

.summary-box {
  border: 2px dashed var(--python-yellow-dark);
  border-radius: var(--radius-md);
  padding: 20px;
  font-weight: 600;
}

/* أزرار التالي والسابق */
.lesson-nav {
  display: flex;
  justify-content: space-between;
  gap: 14px;
  margin-top: 40px;
}

.lesson-nav button {
  flex: 1;
  padding: 15px 18px;
  border-radius: var(--radius-sm);
  background: var(--surface-solid);
  border: 1px solid var(--border-soft);
  font-weight: 700;
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  transition: background var(--transition);
}

.lesson-nav button:hover:not(:disabled) {
  background: var(--bg-alt);
}

.lesson-nav button:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.mark-done-btn {
  width: 100%;
  padding: 16px;
  border-radius: var(--radius-sm);
  background: linear-gradient(120deg, #1f9d55, #27ae60);
  color: #fff;
  font-weight: 700;
  font-size: 1rem;
  margin-top: 30px;
}

.mark-done-btn.completed {
  background: var(--text-muted);
}

/* ---------- 9. رسومات توضيحية (Diagrams) ---------- */
.diagram {
  display: flex;
  gap: 14px;
  flex-wrap: wrap;
  align-items: center;
  justify-content: center;
  padding: 26px 16px;
  background: var(--bg-alt);
  border-radius: var(--radius-md);
  margin-bottom: 24px;
}

.diagram-box {
  min-width: 90px;
  padding: 14px 18px;
  background: var(--surface-solid);
  border: 2px solid var(--python-blue);
  border-radius: var(--radius-sm);
  text-align: center;
  font-family: "Courier New", monospace;
  font-weight: 700;
  direction: ltr;
}

.diagram-arrow {
  font-size: 1.4rem;
  color: var(--python-blue);
}

.diagram-box.yellow {
  border-color: var(--python-yellow-dark);
}

.diagram-flow {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 8px;
}

.diagram-flow .branch {
  display: flex;
  gap: 30px;
}

.diagram-pill {
  padding: 10px 16px;
  border-radius: 999px;
  background: var(--surface-solid);
  border: 2px dashed var(--python-blue);
  font-size: 0.85rem;
  font-weight: 700;
}

.diagram-cycle {
  display: flex;
  align-items: center;
  gap: 10px;
  font-family: "Courier New", monospace;
  font-weight: 700;
}

.diagram-cycle .circle {
  width: 70px;
  height: 70px;
  border-radius: 50%;
  border: 3px solid var(--python-blue);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--surface-solid);
}

/* ---------- 10. قسم "حول السلسلة" ---------- */
.about-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 22px;
}

.about-card {
  background: var(--surface-solid);
  border: 1px solid var(--border-soft);
  border-radius: var(--radius-md);
  padding: 28px 22px;
  box-shadow: 0 16px 30px -24px var(--shadow-color);
}

.about-card .about-icon {
  font-size: 1.8rem;
  margin-bottom: 14px;
}

.about-card h3 {
  font-family: var(--font-display);
  margin-bottom: 10px;
  font-size: 1.1rem;
}

.about-card p {
  color: var(--text-muted);
  font-size: 0.94rem;
}

/* ---------- 11. التذييل Footer ---------- */
.site-footer {
  background: var(--bg-alt);
  border-top: 1px solid var(--border-soft);
  padding: 50px 0 26px;
  margin-top: 60px;
}

.footer-inner {
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 22px;
  text-align: center;
}

.footer-brand {
  font-family: var(--font-display);
  font-weight: 800;
  font-size: 1.15rem;
}

.footer-social {
  display: flex;
  gap: 16px;
}

.footer-social a {
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 12px 20px;
  border-radius: 999px;
  background: var(--surface-solid);
  border: 1px solid var(--border-soft);
  font-weight: 600;
  font-size: 0.9rem;
  transition: transform var(--transition), background var(--transition);
}

.footer-social a:hover {
  transform: translateY(-3px);
  background: var(--python-blue);
  color: #fff;
}

.footer-copy {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ---------- 12. تجاوبية الشاشات الصغيرة ---------- */
@media (max-width: 960px) {
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .lessons-path {
    grid-template-columns: repeat(2, 1fr);
  }
  .lessons-path .lesson-card:nth-child(6n+4),
  .lessons-path .lesson-card:nth-child(6n+5),
  .lessons-path .lesson-card:nth-child(6n+6) {
    margin-top: 0;
  }
  .about-grid {
    grid-template-columns: 1fr;
  }
}

@media (max-width: 640px) {
  .nav-links {
    display: none;
  }
  .stats-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .lessons-path {
    grid-template-columns: 1fr;
  }
  .hero {
    padding: 60px 0 50px;
  }
  .hero-logo {
    width: 96px;
    height: 96px;
  }
  .lesson-nav {
    flex-direction: column;
  }
  .section {
    padding: 60px 0 20px;
  }
}

/* ---------- 13. حالة عدم وجود نتائج بحث ---------- */
.no-results {
  text-align: center;
  padding: 40px;
  color: var(--text-muted);
  grid-column: 1 / -1;
}

/* ---------- 14. تلميحات صغيرة (Skip link) ---------- */
.skip-link {
  position: absolute;
  right: -999px;
  top: 0;
  background: var(--python-blue);
  color: #fff;
  padding: 10px 16px;
  border-radius: 0 0 0 10px;
  z-index: 999;
}

.skip-link:focus {
  right: 0;
}