@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700;800&display=swap');

:root {
  --color-primary: #0B1F4D;
  --color-secondary: #2563EB;
  --color-light-blue: #EAF2FF;
  --color-accent: #F97316;
  --color-bg: #F8FAFC;
  --color-text: #172033;
  --color-muted: #64748B;
  --color-white: #FFFFFF;

  --container: 1180px;
  --radius-sm: 8px;
  --radius-md: 16px;
  --radius-lg: 30px;
  --shadow-soft: 0 16px 40px rgba(15, 23, 42, 0.06);
  --shadow-hover: 0 24px 48px rgba(15, 23, 42, 0.12);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

* {
  box-sizing: border-box;
}

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  line-height: 1.6;
  margin: 0;
  padding: 0;
  background-color: var(--color-bg);
  color: var(--color-text);
  -webkit-font-smoothing: antialiased;
}

.container {
  max-width: var(--container);
  margin: 0 auto;
  padding: 0 20px;
}

a {
  color: var(--color-secondary);
  text-decoration: none;
  transition: var(--transition);
}

a:hover {
  color: var(--color-primary);
}

/* Typography & Badges */
h1, h2, h3, h4, h5, h6 {
  color: var(--color-primary);
  font-weight: 700;
  line-height: 1.3;
  margin-top: 0;
}

.highlight {
  color: var(--color-secondary);
  position: relative;
  display: inline-block;
}

.highlight::after {
  content: '';
  position: absolute;
  left: 0;
  bottom: 4px;
  width: 100%;
  height: 8px;
  background-color: rgba(37, 99, 235, 0.1);
  z-index: -1;
  border-radius: 4px;
}

.badge-tagline {
  display: inline-block;
  font-size: 0.85rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 1.5px;
  color: var(--color-accent);
  background-color: rgba(249, 115, 22, 0.08);
  padding: 6px 16px;
  border-radius: 50px;
  margin-bottom: 20px;
}

.section-header {
  margin-bottom: 50px;
  max-width: 700px;
}

.section-header.text-center {
  margin-left: auto;
  margin-right: auto;
  text-align: center;
}

.section-header.text-between {
  display: flex;
  align-items: flex-end;
  justify-content: space-between;
  max-width: 100%;
}

.section-title {
  font-size: clamp(2rem, 4vw, 2.5rem);
  margin-bottom: 15px;
}

.section-desc {
  color: var(--color-muted);
  font-size: 1.1rem;
  margin: 0;
}

/* Header */
.site-header {
  background: var(--color-white);
  box-shadow: 0 4px 20px rgba(15, 23, 42, 0.04);
  position: sticky;
  top: 0;
  z-index: 100;
  padding: 18px 0;
}

.site-header .container {
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.site-title {
  margin: 0;
  font-size: 1.6rem;
  line-height: 1;
  font-weight: 800;
}

.site-title a {
  color: var(--color-primary);
  font-weight: 800;
}

.main-navigation ul {
  list-style: none;
  margin: 0;
  padding: 0;
  display: flex;
  gap: 25px;
}

.main-navigation a {
  color: var(--color-text);
  font-weight: 600;
}

.main-navigation a:hover {
  color: var(--color-secondary);
}

.menu-toggle {
  display: none;
  background: none;
  border: none;
  font-size: 1.5rem;
  cursor: pointer;
  color: var(--color-primary);
}

/* Header CTA: Login & User Menu */
.header-cta {
  display: flex;
  align-items: center;
  gap: 10px;
  flex-shrink: 0;
}

/* Logged-in: user menu wrapper */
.header-user-menu {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* Dashboard button when logged in */
.header-dashboard-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  padding: 10px 20px;
  max-width: 200px;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
}

.user-avatar-icon {
  flex-shrink: 0;
}

/* Logout icon button */
.header-logout-btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 38px;
  height: 38px;
  border-radius: 50%;
  background-color: rgba(15, 23, 42, 0.05);
  color: var(--color-muted);
  font-size: 1.1rem;
  text-decoration: none;
  transition: var(--transition);
  flex-shrink: 0;
}

.header-logout-btn:hover {
  background-color: rgba(220, 38, 38, 0.08);
  color: #dc2626;
}

/* Login button icon */
#header-login-btn {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
  padding: 10px 20px;
}

/* Buttons */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border-radius: var(--radius-sm);
  font-weight: 700;
  font-size: 0.95rem;
  border: 2px solid transparent;
  cursor: pointer;
  transition: var(--transition);
  gap: 8px;
}

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

.btn-primary:hover {
  background-color: var(--color-primary);
  color: var(--color-white);
  transform: translateY(-2px);
}

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

.btn-accent:hover {
  background-color: #ea580c;
  color: var(--color-white);
  transform: translateY(-2px);
}

.btn-outline {
  background-color: transparent;
  border-color: var(--color-secondary);
  color: var(--color-secondary);
  border: 2px solid var(--color-secondary);
  text-align: center;
  cursor: pointer;
}

.btn-outline:hover {
  background-color: var(--color-secondary);
  color: var(--color-white) !important;
  transform: translateY(-2px);
}

.btn-lg {
  padding: 15px 36px;
  border-radius: var(--radius-sm);
  font-size: 1.05rem;
}

/* Cards & General Elements */
.card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  padding: 30px;
}

.card-lift {
  transition: var(--transition);
}

.card-lift:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

/* 1. HERO SECTION */
.hero-section {
  min-height: calc(100vh - 75px); /* full screen minus header */
  padding: 80px 0;
  background: linear-gradient(135deg, var(--color-white) 0%, var(--color-light-blue) 100%);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
}

.hero-container {
  display: grid;
  grid-template-columns: 1fr 1fr;
  align-items: center;
  gap: 50px;
  width: 100%;
  max-width: 100%; /* Bỏ giới hạn 1180px để tràn viền */
  padding: 0 5%; /* Cách viền 5% cho đẹp */
}

.hero-content {
  position: relative;
  z-index: 2;
}

.hero-content > * {
  opacity: 0;
  transform: translateY(30px);
  transition: transform 800ms cubic-bezier(0.25, 1, 0.5, 1), opacity 800ms cubic-bezier(0.25, 1, 0.5, 1);
}

.hero-section.active .hero-content > * {
  opacity: 1;
  transform: translateY(0);
}

.hero-section.active .badge-tagline {
  transition-delay: 0.1s;
}

.hero-section.active .hero-title {
  transition-delay: 0.3s;
}

.hero-section.active .hero-subtitle {
  transition-delay: 0.5s;
}

.hero-section.active .hero-buttons {
  transition-delay: 0.7s;
}

.hero-title {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  margin-bottom: 20px;
}

.hero-subtitle {
  font-size: 1.15rem;
  color: var(--color-muted);
  margin-bottom: 35px;
  max-width: 600px;
}

.hero-buttons {
  display: flex;
  gap: 15px;
  flex-wrap: wrap;
}

/* Hero Image & Layout Shapes */
.hero-image-wrapper {
  position: relative;
  height: 578px; /* Fixed height for shape alignments */
  width: 100%;
  flex-shrink: 0;
}

@media (max-width: 991px) {
  .hero-image-wrapper {
    height: auto;
    min-height: 300px;
    display: none;
  }
}

.main-slider__layer {
  position: absolute;
  bottom: 0;
  z-index: 3;
  left: 0;
}

.main-slider__layer-thumb {
  position: relative;
  z-index: 2;
  overflow: hidden;
}

.main-slider__layer-thumb img {
  display: block;
  max-width: 455px;
  width: auto !important;
  height: auto;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateX(200px);
}

.hero-section.active .main-slider__layer-thumb img {
  visibility: visible;
  opacity: 1;
  transform: translateX(0) translateY(0);
  transition-delay: 1.2s; /* Animate entry of the person */
  animation: floatImg 6s ease-in-out infinite;
  animation-delay: 2.2s;
}

.main-slider__layer svg {
  width: 130%; /* Tự động to ra so với khung */
  height: auto;
  position: absolute;
  fill: var(--color-secondary); /* Large blue background blob */
  bottom: 0;
  z-index: -1;
  left: -15%;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(100%);
}

.hero-section.active .main-slider__layer svg {
  visibility: visible;
  opacity: 0.85;
  transform: translateY(0);
  transition-delay: 0.6s;
}

/* 9 Decorative Floating/Rotating Shapes */
.main-slider__shape-one {
  position: absolute;
  top: 60px;
  left: 10px;
  z-index: 3;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(100px);
}

.hero-section.active .main-slider__shape-one {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 1.5s;
}

.main-slider__shape-one img {
  animation: float-bob-y-2 4s infinite linear;
}

.main-slider__shape-two {
  position: absolute;
  bottom: 200px;
  left: -40px;
  z-index: 3;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(-100px);
}

.hero-section.active .main-slider__shape-two {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 1.6s;
}

.main-slider__shape-two img {
  animation: rotated 20s infinite linear;
}

.main-slider__shape-three {
  position: absolute;
  bottom: 78px;
  z-index: 3;
  left: -20px;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(100px);
}

.hero-section.active .main-slider__shape-three {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 1.7s;
}

.main-slider__shape-three svg {
  width: 152px;
  height: 152px;
}

.main-slider__shape-three svg circle {
  stroke-dasharray: 1200;
  stroke-dashoffset: 1200;
  animation: dash 5s infinite linear;
}

.main-slider__shape-four {
  position: absolute;
  bottom: 280px;
  z-index: 3;
  left: 10px;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(200px);
}

.hero-section.active .main-slider__shape-four {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 1.8s;
}

.main-slider__shape-four svg {
  width: 32px;
  height: 32px;
}

.main-slider__shape-four svg circle {
  stroke-dasharray: 1200;
  stroke-dashoffset: 1200;
  animation: dash4 3s infinite linear;
}

.main-slider__shape-five {
  position: absolute;
  top: 150px;
  z-index: 3;
  left: -40px;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(-200px);
}

.hero-section.active .main-slider__shape-five {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 1.9s;
}

.main-slider__shape-five svg {
  width: 124px;
  height: 101px;
  fill: var(--color-accent);
  animation: zump-one 1.2s infinite alternate;
}

.main-slider__shape-six {
  position: absolute;
  top: 60px;
  z-index: 3;
  right: 60px;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(-200px);
}

.hero-section.active .main-slider__shape-six {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 2.0s;
}

.main-slider__shape-six img {
  animation: float-bob-y-2 4s infinite linear;
}

.main-slider__shape-seven {
  position: absolute;
  top: 100px;
  right: 10px;
  z-index: 3;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(-200px);
}

.hero-section.active .main-slider__shape-seven {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 2.1s;
}

.main-slider__shape-seven img {
  animation: rotated 12s infinite linear;
}

.main-slider__shape-eight {
  position: absolute;
  bottom: 220px;
  right: -30px;
  width: 110px;
  height: 110px;
  background-color: var(--color-accent);
  border-radius: 50%;
  border: 7px solid #E7E9F4;
  color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 3;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(200px);
}

.hero-section.active .main-slider__shape-eight {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 2.2s;
}

.main-slider__shape-eight svg {
  animation: rotated2 6s infinite linear;
  color: var(--color-white);
}

.main-slider__shape-nine {
  position: absolute;
  bottom: 78px;
  right: 20px;
  z-index: 3;
  transition: transform 1000ms ease, opacity 1000ms ease;
  visibility: hidden;
  opacity: 0;
  transform: translateY(200px);
}

.hero-section.active .main-slider__shape-nine {
  visibility: visible;
  opacity: 1;
  transform: translateY(0);
  transition-delay: 2.3s;
}

.main-slider__shape-nine img {
  animation: float-bob-y-2 4s infinite linear;
}

/* Keyframe animations */
@keyframes dash {
  0% {
    stroke-dashoffset: 1200;
    stroke: var(--color-accent);
  }
  50% {
    stroke: var(--color-secondary);
  }
  100% {
    stroke-dashoffset: 0;
    stroke: var(--color-accent);
  }
}

@keyframes dash4 {
  0% {
    stroke-dashoffset: 1200;
  }
  100% {
    stroke-dashoffset: 0;
  }
}

@keyframes zump-one {
  0% {
    transform: translateY(0);
  }
  100% {
    transform: translateY(-15px);
  }
}

@keyframes float-bob-y-2 {
  0%, 100% {
    transform: translateY(0px) translateX(0px) rotate(0deg);
  }
  50% {
    transform: translateY(10px) translateX(10px) rotate(5deg);
  }
}

@keyframes rotated {
  0% {
    transform: rotate(0);
  }
  100% {
    transform: rotate(360deg);
  }
}

@keyframes rotated2 {
  0% {
    transform: rotate(0);
  }
  50% {
    transform: rotate(45deg);
  }
  100% {
    transform: rotate(0);
  }
}

@keyframes floatImg {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-15px); }
}

/* 2. PROBLEMS SECTION */
.problems-section {
  padding: 90px 0;
  background-color: var(--color-white);
}

.problems-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(250px, 1fr));
  gap: 30px;
}

.problem-card {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: 35px 30px;
  position: relative;
  overflow: hidden;
  border-bottom: 4px solid transparent;
  transition: var(--transition);
}

.problem-card:hover {
  transform: translateY(-8px);
  box-shadow: var(--shadow-hover);
  border-bottom-color: var(--color-accent);
  background: var(--color-white);
}

.card-icon {
  margin-bottom: 25px;
  display: inline-flex;
  align-items: center;
  justify-content: center;
}

.error-icon {
  color: var(--color-accent);
  background-color: rgba(249, 115, 22, 0.08);
  width: 60px;
  height: 60px;
  border-radius: 12px;
}

.card-title {
  font-size: 1.25rem;
  margin-bottom: 12px;
}

.card-text {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin: 0;
}

/* 3. ABOUT SECTION (TUTOR INTRO) */
.about-section {
  padding: 100px 0;
  background-color: var(--color-bg);
}

.about-container {
  display: grid;
  grid-template-columns: 1fr 1.1fr;
  align-items: center;
  gap: 60px;
}

.about-image-wrapper {
  position: relative;
}

.about-image-inner {
  position: relative;
  z-index: 2;
  overflow: hidden;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
}

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

.about-shape-one {
  position: absolute;
  width: calc(100% - 30px);
  height: calc(100% - 30px);
  border: 4px dashed var(--color-secondary);
  border-radius: var(--radius-lg);
  left: 20px;
  top: 20px;
  z-index: 1;
}

.about-shape-two {
  position: absolute;
  right: -30px;
  top: -30px;
  z-index: 3;
}

.about-shape-three {
  position: absolute;
  left: -20px;
  bottom: 20px;
  z-index: 3;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.about-shape-three span {
  width: 30px;
  height: 4px;
  background-color: var(--color-accent);
  display: block;
  opacity: 0.3;
}

.about-content {
  position: relative;
}

.about-text {
  color: var(--color-muted);
  font-size: 1.05rem;
  margin-bottom: 30px;
}

.about-features {
  margin-bottom: 35px;
}

.about-feature-box {
  display: flex;
  gap: 15px;
  background-color: var(--color-white);
  padding: 20px;
  border-radius: var(--radius-md);
  box-shadow: 0 4px 15px rgba(0, 0, 0, 0.02);
}

.about-feature-icon {
  color: var(--color-secondary);
  flex-shrink: 0;
}

.about-feature-title {
  font-size: 1.1rem;
  margin-bottom: 6px;
}

.about-feature-text {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin: 0;
}

.about-meta {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 20px;
  flex-wrap: wrap;
  border-top: 1px solid rgba(0,0,0,0.06);
  padding-top: 25px;
}

.about-author {
  display: flex;
  align-items: center;
  gap: 15px;
}

.author-avatar {
  width: 55px;
  height: 55px;
  border-radius: 50%;
  object-fit: cover;
}

.author-info {
  display: flex;
  flex-direction: column;
}

.author-sign {
  max-width: 100px;
  height: auto;
  margin-bottom: 4px;
}

.author-name {
  font-size: 0.85rem;
  font-weight: 700;
  color: var(--color-primary);
  margin: 0;
}

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

.contact-icon {
  background-color: var(--color-secondary);
  color: var(--color-white);
  width: 45px;
  height: 45px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
}

.contact-info {
  display: flex;
  flex-direction: column;
}

.contact-label {
  font-size: 0.8rem;
  color: var(--color-muted);
  margin: 0 0 2px 0;
}

.contact-phone {
  font-size: 1.15rem;
  margin: 0;
}

.contact-phone a {
  color: var(--color-primary);
}

.contact-phone a:hover {
  color: var(--color-secondary);
}

/* 4. SUBJECT SECTION */
.subjects-section {
  padding: 90px 0;
  background-color: var(--color-white);
}

.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 30px;
}

.subject-card {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  padding: 40px 30px;
  text-align: center;
}

.subject-img-holder {
  width: 130px;
  height: 130px;
  margin: 0 auto 25px auto;
  border-radius: 50%;
  background-color: var(--color-white);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  box-shadow: 0 8px 20px rgba(0, 0, 0, 0.02);
  transition: var(--transition);
}

.subject-card:hover .subject-img-holder {
  transform: scale(1.08);
}

.subject-img {
  width: 80px;
  height: 80px;
  object-fit: contain;
}

.subject-tag {
  display: inline-block;
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-secondary);
  background-color: rgba(37, 99, 235, 0.06);
  padding: 4px 12px;
  border-radius: 50px;
  margin-bottom: 12px;
}

.subject-title {
  font-size: 1.3rem;
  margin-bottom: 10px;
}

.subject-desc {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin-bottom: 20px;
}

.subject-link {
  font-weight: 700;
  font-size: 0.95rem;
  display: inline-flex;
  align-items: center;
  gap: 5px;
}

/* 5. STATS COUNTER SECTION */
.stats-section {
  padding: 60px 0;
  background-color: var(--color-primary);
  color: var(--color-white);
}

.stats-container {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 40px;
  text-align: center;
}

.stat-item {
  position: relative;
}

.stats-container .stat-item:not(:last-child)::after {
  content: '';
  position: absolute;
  right: -20px;
  top: 50%;
  transform: translateY(-50%);
  width: 1px;
  height: 60px;
  background-color: rgba(255, 255, 255, 0.15);
}

.stat-number {
  font-size: clamp(2.5rem, 5vw, 3.5rem);
  color: var(--color-accent);
  margin-bottom: 8px;
}

.stat-label {
  color: var(--color-light-blue);
  font-size: 1.05rem;
  margin: 0;
  font-weight: 600;
}

/* 6. FEATURED EXERCISES SECTION */
.exercises-section {
  padding: 90px 0;
  background-color: var(--color-bg);
}

.exercises-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  gap: 30px;
}

.exercise-card {
  background: var(--color-white);
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.exercise-img-holder {
  position: relative;
  overflow: hidden;
  padding-top: 65%; /* aspect ratio 16:10 */
}

.exercise-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.exercise-card:hover .exercise-img {
  transform: scale(1.06);
}

.exercise-grade {
  position: absolute;
  left: 20px;
  top: 20px;
  background-color: var(--color-accent);
  color: var(--color-white);
  font-weight: 700;
  font-size: 0.8rem;
  padding: 4px 12px;
  border-radius: var(--radius-sm);
  z-index: 2;
}

.exercise-content {
  padding: 25px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.exercise-meta {
  display: flex;
  gap: 15px;
  margin-bottom: 12px;
  font-size: 0.85rem;
  color: var(--color-muted);
}

.meta-item {
  display: inline-flex;
  align-items: center;
  gap: 6px;
}

.exercise-title {
  font-size: 1.15rem;
  margin-bottom: 12px;
}

.exercise-title a {
  color: var(--color-primary);
}

.exercise-title a:hover {
  color: var(--color-secondary);
}

.exercise-excerpt {
  color: var(--color-muted);
  font-size: 0.9rem;
  margin: 0 0 20px 0;
  flex-grow: 1;
}

.exercise-footer {
  border-top: 1px solid rgba(0,0,0,0.06);
  padding-top: 15px;
}

.link-btn {
  font-weight: 700;
  color: var(--color-primary);
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.9rem;
}

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

/* 7. LEARNING PROCESS STEPS SECTION */
.process-section {
  padding: 90px 0;
  background-color: var(--color-white);
}

.process-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(220px, 1fr));
  gap: 30px;
  position: relative;
}

.process-step {
  position: relative;
  padding: 0 10px;
}

.step-number {
  font-size: 3.5rem;
  font-weight: 800;
  color: rgba(37, 99, 235, 0.08);
  line-height: 1;
  margin-bottom: 15px;
  transition: var(--transition);
}

.process-step:hover .step-number {
  color: rgba(37, 99, 235, 0.18);
  transform: translateY(-5px);
}

.step-title {
  font-size: 1.2rem;
  margin-bottom: 10px;
}

.step-desc {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin: 0;
}

/* 8. TESTIMONIALS SECTION */
.testimonials-section {
  padding: 95px 0;
  background-color: var(--color-bg);
}

.testimonials-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(320px, 1fr));
  gap: 30px;
}

.testimonial-card {
  position: relative;
  border-top: 4px solid var(--color-secondary);
}

.quote-icon {
  font-size: 5rem;
  line-height: 1;
  color: rgba(37, 99, 235, 0.1);
  position: absolute;
  right: 30px;
  top: 10px;
  font-family: Georgia, serif;
}

.testimonial-text {
  color: var(--color-text);
  font-size: 1.02rem;
  line-height: 1.7;
  margin: 0 0 25px 0;
  position: relative;
  z-index: 2;
  font-style: italic;
}

.testimonial-author {
  display: flex;
  align-items: center;
  gap: 15px;
}

.author-img {
  width: 50px;
  height: 50px;
  border-radius: 50%;
  object-fit: cover;
}

.testimonial-author .author-name {
  font-size: 1rem;
  font-weight: 700;
  color: var(--color-primary);
  margin-bottom: 2px;
}

.testimonial-author .author-title {
  font-size: 0.85rem;
  color: var(--color-muted);
  margin: 0;
}

/* 9. BLOG SECTION */
.blog-section {
  padding: 90px 0;
  background-color: var(--color-white);
}

.blog-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 30px;
}

.blog-card {
  background: var(--color-bg);
  border-radius: var(--radius-md);
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.02);
  overflow: hidden;
  display: flex;
  flex-direction: column;
}

.blog-img-holder {
  position: relative;
  overflow: hidden;
  padding-top: 60%;
}

.blog-img {
  position: absolute;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  transition: var(--transition);
}

.blog-card:hover .blog-img {
  transform: scale(1.06);
}

.blog-date {
  position: absolute;
  right: 20px;
  bottom: 15px;
  background-color: var(--color-secondary);
  color: var(--color-white);
  font-weight: 700;
  font-size: 0.85rem;
  padding: 8px 16px;
  border-radius: var(--radius-sm);
  z-index: 2;
  box-shadow: 0 4px 10px rgba(37, 99, 235, 0.2);
}

.blog-content {
  padding: 25px 25px 25px 25px;
  display: flex;
  flex-direction: column;
  flex-grow: 1;
}

.blog-category {
  font-size: 0.8rem;
  font-weight: 700;
  color: var(--color-accent);
  text-transform: uppercase;
  margin-bottom: 10px;
  letter-spacing: 1px;
}

.blog-title {
  font-size: 1.2rem;
  margin-bottom: 12px;
}

.blog-title a {
  color: var(--color-primary);
}

.blog-title a:hover {
  color: var(--color-secondary);
}

.blog-excerpt {
  color: var(--color-muted);
  font-size: 0.95rem;
  margin: 0 0 20px 0;
  flex-grow: 1;
}

.blog-footer {
  border-top: 1px solid rgba(0,0,0,0.06);
  padding-top: 15px;
}

/* 10. FINAL CTA SECTION */
.final-cta-section {
  padding: 80px 0 100px 0;
  background-color: var(--color-bg);
}

.cta-container {
  display: grid;
  grid-template-columns: 1.2fr 0.8fr;
  align-items: center;
  gap: 50px;
  background-color: var(--color-primary);
  color: var(--color-white);
  padding: 50px;
  border-radius: var(--radius-lg);
  position: relative;
  overflow: hidden;
  box-shadow: var(--shadow-hover);
}

.cta-content {
  position: relative;
  z-index: 2;
}

.cta-title {
  color: var(--color-white);
  font-size: clamp(1.8rem, 4vw, 2.3rem);
  margin-bottom: 15px;
}

.cta-text {
  color: var(--color-light-blue);
  font-size: 1.1rem;
  margin-bottom: 30px;
  max-width: 600px;
}

.cta-form-wrapper {
  max-width: 550px;
}

.cta-simple-form {
  display: flex;
  gap: 12px;
  flex-wrap: wrap;
  align-items: center;
}

.form-input {
  flex: 1;
  min-width: 180px;
  padding: 14px 20px;
  border-radius: var(--radius-sm);
  border: 1px solid rgba(255, 255, 255, 0.15);
  background-color: rgba(255, 255, 255, 0.08);
  color: var(--color-white);
  font-size: 0.95rem;
  font-family: inherit;
  outline: none;
  transition: var(--transition);
}

.form-input::placeholder {
  color: rgba(255, 255, 255, 0.5);
}

.form-input:focus {
  border-color: var(--color-secondary);
  background-color: rgba(255, 255, 255, 0.15);
}

.cta-image-wrapper {
  position: relative;
  z-index: 2;
  text-align: right;
  display: flex;
  justify-content: flex-end;
}

.cta-img {
  max-width: 100%;
  height: auto;
  object-fit: contain;
}

/* Footer & Branding fixes */
.site-footer {
  background: #06122c;
  color: var(--color-white);
  padding: 60px 0 20px;
  margin-top: 0;
}

.footer-widget h3 {
  color: var(--color-white);
  font-weight: 700;
  margin-bottom: 20px;
}

.footer-widget ul {
  list-style: none;
  padding: 0;
  margin: 0;
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.footer-widget ul a {
  color: var(--color-light-blue);
  opacity: 0.85;
}

.footer-widget ul a:hover {
  opacity: 1;
  color: var(--color-secondary);
  padding-left: 5px;
}

/* Responsive Overrides */
@media (max-width: 991px) {
  .hero-section {
    min-height: auto;
    padding: 70px 0;
  }

  .hero-container,
  .about-container,
  .cta-container {
    grid-template-columns: 1fr;
    text-align: center;
    gap: 40px;
  }

  .hero-buttons {
    justify-content: center;
  }

  .about-image-wrapper {
    max-width: 450px;
    margin: 0 auto;
  }

  .about-meta {
    justify-content: center;
  }

  .cta-image-wrapper {
    justify-content: center;
    display: none; /* Hide illustrative cta image on tablets/mobile to keep it compact */
  }

  .cta-simple-form {
    flex-direction: column;
  }
  
  .stats-container .stat-item:not(:last-child)::after {
    display: none;
  }
}

@media (max-width: 768px) {
  .menu-toggle {
    display: block;
  }
  
  .site-header .container {
    position: relative;
  }

  .main-navigation {
    position: static;
  }

  .main-navigation ul {
    display: none;
    flex-direction: column;
    position: absolute;
    top: 100%;
    left: 0;
    width: 100%;
    background: var(--color-white);
    padding: 20px;
    box-shadow: 0 10px 20px rgba(0,0,0,0.05);
    gap: 15px;
    z-index: 200;
  }

  .main-navigation.toggled ul {
    display: flex;
  }
  
  /* On mobile: hide the full login button, keep compact user menu */
  .header-cta {
    gap: 6px;
  }

  #header-login-btn {
    display: none; /* hide full login button on small screens */
  }

  .header-dashboard-btn {
    font-size: 0;      /* hide text, keep icon */
    padding: 10px 12px;
    width: 38px;
    height: 38px;
    border-radius: 50%;
    min-width: unset;
  }

  .header-dashboard-btn .user-avatar-icon {
    font-size: 1rem;
  }
}

/* ==========================================================================
   Exercise Archive & Single Custom Styles (Premium Design System)
   ========================================================================== */

/* Layout & General Classes */
.exercise-archive-main,
.exercise-single-main {
  padding: 60px 0 100px;
}

.text-center {
  text-align: center;
}

.btn-block {
  display: block;
  width: 100%;
}

/* Duplicate .btn-outline override removed — consolidated above */
/* Keep only the inline-block fallback for non-flex contexts */
.section-header.text-between .btn-outline,
.exercises-section .btn-outline,
.blog-section .btn-outline {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 24px;
  font-weight: 600;
  font-size: 0.95rem;
  white-space: nowrap;
}

/* Archive Layout Grid */
.archive-header {
  margin-bottom: 50px;
}

.archive-header .page-title {
  font-size: clamp(2rem, 4vw, 2.75rem);
  margin-bottom: 15px;
}

.archive-header .page-description {
  font-size: 1.1rem;
  color: var(--color-muted);
  max-width: 700px;
  margin: 0 auto;
}

.exercise-archive-layout {
  display: grid;
  grid-template-columns: 280px 1fr;
  gap: 40px;
  align-items: start;
}

/* Sidebar Filters */
.exercise-sidebar {
  position: sticky;
  top: 100px;
}

.filter-card {
  background: var(--color-white);
  padding: 30px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(15, 23, 42, 0.02);
}

.filter-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 25px;
  padding-bottom: 12px;
  border-bottom: 2px solid var(--color-light-blue);
  color: var(--color-primary);
}

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

.filter-group label {
  display: block;
  font-weight: 600;
  font-size: 0.88rem;
  color: var(--color-primary);
  margin-bottom: 8px;
}

.filter-group select {
  width: 100%;
  padding: 12px 16px;
  border: 1px solid rgba(100, 116, 139, 0.15);
  border-radius: var(--radius-sm);
  font-size: 0.9rem;
  font-family: inherit;
  background-color: var(--color-bg);
  color: var(--color-text);
  transition: var(--transition);
  outline: none;
}

.filter-group select:focus {
  border-color: var(--color-secondary);
  background-color: var(--color-white);
  box-shadow: 0 0 0 3px rgba(37, 99, 235, 0.1);
}

.filter-actions {
  margin-top: 30px;
  display: flex;
  flex-direction: column;
  gap: 10px;
}

.reset-filter-btn {
  background: transparent;
  color: var(--color-muted);
  border: 1px solid rgba(100, 116, 139, 0.2);
  padding: 10px;
  font-size: 0.9rem;
  border-radius: var(--radius-sm);
  transition: var(--transition);
}

.reset-filter-btn:hover {
  background: rgba(100, 116, 139, 0.05);
  color: var(--color-primary);
}

/* Exercise Grid Content */
.exercise-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(290px, 1fr));
  gap: 30px;
}

.exercise-card {
  background: var(--color-white);
  padding: 30px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(15, 23, 42, 0.02);
  display: flex;
  flex-direction: column;
  transition: var(--transition);
  height: 100%;
}

.exercise-card:hover {
  transform: translateY(-6px);
  box-shadow: var(--shadow-hover);
}

.exercise-card-meta {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 15px;
}

.badge {
  display: inline-block;
  font-size: 0.75rem;
  font-weight: 600;
  padding: 4px 12px;
  border-radius: 50px;
}

.badge-grade {
  background: rgba(37, 99, 235, 0.08);
  color: var(--color-secondary);
}

.badge-subject {
  background: rgba(249, 115, 22, 0.08);
  color: var(--color-accent);
}

.exercise-card-title {
  font-size: 1.25rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 12px;
}

.exercise-card-title a {
  color: var(--color-primary);
}

.exercise-card-title a:hover {
  color: var(--color-secondary);
}

.exercise-card-excerpt {
  font-size: 0.92rem;
  color: var(--color-muted);
  line-height: 1.6;
  margin-bottom: 20px;
  flex-grow: 1;
}

.exercise-card-specs {
  display: flex;
  flex-wrap: wrap;
  gap: 15px;
  margin-bottom: 20px;
  padding-top: 15px;
  border-top: 1px solid rgba(15, 23, 42, 0.05);
  font-size: 0.85rem;
}

.spec-item {
  display: flex;
  gap: 5px;
  align-items: center;
}

.spec-label {
  color: var(--color-muted);
}

.spec-val {
  font-weight: 600;
  color: var(--color-primary);
}

.exercise-card-badges {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  margin-bottom: 20px;
}

.status-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  font-weight: 600;
  padding: 4px 10px;
  border-radius: 4px;
}

.status-badge.has-answer {
  background-color: #F0FDF4;
  color: #16A34A;
}

.status-badge.has-answer .dot {
  background-color: #16A34A;
}

.status-badge.has-solution {
  background-color: #EFF6FF;
  color: #2563EB;
}

.status-badge.has-solution .dot {
  background-color: #2563EB;
}

.status-badge .dot {
  width: 6px;
  height: 6px;
  border-radius: 50%;
  display: inline-block;
}

.exercise-card-action {
  margin-top: auto;
}

/* Pagination */
.pagination-wrapper {
  margin-top: 50px;
  display: flex;
  justify-content: center;
}

.pagination-wrapper .page-numbers {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 44px;
  height: 44px;
  margin: 0 4px;
  border-radius: var(--radius-sm);
  background-color: var(--color-white);
  box-shadow: var(--shadow-soft);
  color: var(--color-primary);
  font-weight: 600;
  transition: var(--transition);
}

.pagination-wrapper .page-numbers.current,
.pagination-wrapper .page-numbers:hover {
  background-color: var(--color-secondary);
  color: var(--color-white) !important;
}

.pagination-wrapper .page-numbers.dots {
  background: transparent;
  box-shadow: none;
  color: var(--color-muted);
}

/* No Results Card */
.no-results-card {
  background: var(--color-white);
  padding: 60px 40px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  max-width: 500px;
  margin: 0 auto;
}

.no-results-icon {
  font-size: 3rem;
  margin-bottom: 20px;
}

.no-results-card h3 {
  font-size: 1.5rem;
  margin-bottom: 10px;
}

.no-results-card p {
  color: var(--color-muted);
  margin-bottom: 25px;
}

/* Single Exercise Page */
.exercise-navigation {
  margin-bottom: 35px;
}

.back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  font-weight: 600;
  color: var(--color-muted);
  transition: var(--transition);
}

.back-link:hover {
  color: var(--color-secondary);
}

.exercise-single-layout {
  display: grid;
  grid-template-columns: 1fr 360px;
  gap: 40px;
  align-items: start;
}

.exercise-single-article {
  background: var(--color-white);
  padding: 50px;
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(15, 23, 42, 0.02);
}

.exercise-header-meta {
  display: flex;
  gap: 8px;
  margin-bottom: 20px;
}

.exercise-single-article .entry-title {
  font-size: clamp(1.8rem, 3.5vw, 2.5rem);
  margin-bottom: 20px;
  color: var(--color-primary);
  line-height: 1.3;
}

.exercise-status-bar {
  display: flex;
  gap: 12px;
  margin-bottom: 35px;
  padding-bottom: 20px;
  border-bottom: 1px solid rgba(15, 23, 42, 0.06);
}

.exercise-single-article .post-thumbnail {
  margin-bottom: 35px;
  border-radius: var(--radius-md);
  overflow: hidden;
}

.exercise-single-article .post-thumbnail img {
  width: 100%;
  height: auto;
  display: block;
}

.exercise-single-article .entry-content .section-title {
  font-size: 1.5rem;
  margin-bottom: 20px;
  border-left: 4px solid var(--color-secondary);
  padding-left: 15px;
  color: var(--color-primary);
}

.exercise-single-article .entry-content {
  font-size: 1.05rem;
  line-height: 1.8;
}

/* Sidebar Widgets */
.exercise-single-sidebar .widget {
  background: var(--color-white);
  padding: 30px;
  border-radius: var(--radius-md);
  box-shadow: var(--shadow-soft);
  border: 1px solid rgba(15, 23, 42, 0.02);
  margin-bottom: 30px;
}

.exercise-single-sidebar .widget-title {
  font-size: 1.2rem;
  margin-bottom: 20px;
  padding-bottom: 10px;
  border-bottom: 2px solid var(--color-light-blue);
  color: var(--color-primary);
}

.spec-list {
  list-style: none;
  padding: 0;
  margin: 0;
}

.spec-list li {
  display: flex;
  align-items: center;
  padding: 12px 0;
  border-bottom: 1px solid rgba(15, 23, 42, 0.04);
}

.spec-list li:last-child {
  border-bottom: none;
}

.spec-icon {
  font-size: 1.1rem;
  margin-right: 12px;
  display: inline-block;
  width: 20px;
  text-align: center;
}

.spec-label {
  color: var(--color-muted);
  flex-grow: 1;
}

.spec-val {
  color: var(--color-primary);
  font-weight: 700;
}

.download-widget p {
  font-size: 0.92rem;
  color: var(--color-muted);
  margin-bottom: 20px;
  line-height: 1.5;
}

.download-widget .btn {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

/* Premium CTA Widget */
.cta-widget {
  background: linear-gradient(135deg, var(--color-primary) 0%, #102657 100%) !important;
  color: var(--color-white);
  border: none !important;
}

.cta-widget .cta-title {
  color: var(--color-white);
  font-size: 1.35rem;
  font-weight: 700;
  margin-bottom: 15px;
}

.cta-widget .cta-text {
  color: rgba(255, 255, 255, 0.85);
  font-size: 0.92rem;
  line-height: 1.6;
  margin-bottom: 25px;
}

/* Responsive Styles */
@media (max-width: 991px) {
  .exercise-archive-layout {
    grid-template-columns: 1fr;
    gap: 30px;
  }
  
  .exercise-sidebar {
    position: static;
  }

  .exercise-single-layout {
    grid-template-columns: 1fr;
    gap: 30px;
  }
}

@media (max-width: 575px) {
  .exercise-single-article {
    padding: 30px 20px;
  }
}