/* ==========================================================================
   CSS VARIABLES & CONFIG
   ========================================================================== */
:root {
  /* Colors */
  --primary-50: #fffbeb;
  --primary-100: #fef3c7;
  --primary-200: #fde68a;
  --primary-300: #fcd34d;
  --primary-400: #fbbf24;
  --primary-500: #f59e0b;
  --primary-600: #202020;
  --primary-700: #202020;
  --neutral-100: #f5f5f5;
  --neutral-200: #e5e5e5;
  --neutral-300: #d4d4d4;
  --neutral-400: #a3a3a3;
  --neutral-500: #737373;
  --neutral-600: #525252;
  --neutral-700: #404040;
  --neutral-900: #171717;

  /* Gradients & Shadows */
  --gradient-primary: linear-gradient(
    135deg,
    #fbbf24 0%,
    #f59e0b 50%,
    #d97706 100%
  );
  --gradient-dark: linear-gradient(
    135deg,
    #1a1a1a 0%,
    #262626 50%,
    #171717 100%
  );
  --shadow-md:
    0 4px 6px -1px rgba(0, 0, 0, 0.1), 0 2px 4px -2px rgba(0, 0, 0, 0.1);
  --shadow-xl:
    0 20px 25px -5px rgba(0, 0, 0, 0.1), 0 8px 10px -6px rgba(0, 0, 0, 0.1);
  --shadow-2xl: 0 25px 50px -12px rgba(0, 0, 0, 0.25);

  /* Spacing & Typography */
  --space-1: 0.25rem;
  --space-2: 0.5rem;
  --space-3: 0.75rem;
  --space-4: 1rem;
  --space-5: 1.25rem;
  --space-6: 1.5rem;
  --space-10: 2.5rem;
  --space-12: 3rem;
  --space-16: 4rem;
  --space-20: 5rem;
  --font-heading: "Prompt", sans-serif;

  /* Borders & Transitions */
  --radius-sm: 0.375rem;
  --radius-md: 0.5rem;
  --radius-lg: 0.75rem;
  --radius-xl: 1rem;
  --radius-2xl: 1.5rem;
  --radius-full: 9999px;
  --transition-base: 200ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slow: 300ms cubic-bezier(0.4, 0, 0.2, 1);
  --transition-slower: 500ms cubic-bezier(0.4, 0, 0.2, 1);
}

/* Global Reset for Components */
button,
a {
  -webkit-tap-highlight-color: transparent;
  user-select: none;
}
button:focus,
a:focus {
  outline: none;
}
button:focus-visible,
a:focus-visible {
  outline: 3px solid var(--primary-500);
  outline-offset: 2px;
  border-radius: var(--radius-sm);
}

/* ==========================================================================
   1. HERO SLIDER
   ========================================================================== */
.hero-section {
  position: relative;
  width: 100%;
  margin: 0 auto;
  height: 450px;
  overflow: hidden;
  background-color: #000;
}

#heroSlider,
.hero-slide {
  width: 100%;
  height: 100%;
  position: absolute;
  top: 0;
  left: 0;
  background-size: cover;
  background-position: center;
  transition: opacity 1s ease-in-out;
}

.hero-content {
  position: absolute;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  text-align: center;
  width: 80%;
  z-index: 100 !important;
  color: #fff;
  pointer-events: auto;
}

.hero-title {
  font-family: var(--font-heading);
  font-size: 3rem;
  font-weight: 700;
  line-height: 1.4;
  margin-bottom: 20px;
  text-shadow: 2px 2px 10px rgba(0, 0, 0, 0.7);
}

.hero-subtitle,
.hero-description {
  font-family: "Prompt", sans-serif;
  font-size: 1.1rem;
  font-weight: 400;
  text-shadow: 1px 1px 5px rgba(0, 0, 0, 0.8);
}

.slider-dots {
  position: absolute;
  bottom: 20px;
  left: 50%;
  transform: translateX(-50%);
  z-index: 11;
  display: flex;
  gap: 10px;
}

.slider-dot {
  width: 12px;
  height: 12px;
  border-radius: 50%;
  background: rgba(255, 255, 255, 0.5);
  border: none;
  cursor: pointer;
  transition: 0.3s;
}

.slider-dot.active {
  background: var(--primary-500);
  transform: scale(1.2);
}

/* ==========================================================================
   2. HEADER BARS & SECTION LAYOUT
   ========================================================================== */
.info-bar,
.subject-header-bar {
  background-color: #161615 !important;
  padding: var(--space-4) !important;
  text-align: center;
  width: 100%;
}

.info-bar-item,
.subject-header-title {
  font-size: 1.2rem !important;
  font-weight: 600 !important;
  color: #ffffff !important;
  margin: 0;
  line-height: 1.2;
}

.premium-section {
  position: relative;
  padding-top: var(--space-12) !important;
  padding-bottom: var(--space-20) !important;
  overflow: hidden;
}

.subjects-section {
  /* background: linear-gradient(to bottom, #f0f2f5 0%, #e8eaed 100%);
  border-top: 1px solid var(--neutral-300); */
  padding-top: var(--space-0) !important;
  padding-bottom: var(--space-12) !important;
}

.tutors-section > .container,
.subjects-section > .container {
  padding-top: var(--space-16) !important;
}

/* Background Patterns */
.section-bg-pattern {
  position: absolute;
  inset: 0;
  background-image:
    radial-gradient(
      circle at 10% 20%,
      rgba(251, 191, 36, 0.03) 0%,
      transparent 50%
    ),
    radial-gradient(
      circle at 90% 80%,
      rgba(59, 130, 246, 0.03) 0%,
      transparent 50%
    );
  pointer-events: none;
}
.subjects-bg-decoration {
  position: absolute;
  top: 0;
  right: 0;
  width: 600px;
  height: 600px;
  background: radial-gradient(
    circle,
    rgba(245, 158, 11, 0.06) 0%,
    transparent 70%
  );
  pointer-events: none;
}

/* ==========================================================================
   3. MODERN TUTOR CARDS
   ========================================================================== */
.tutors-grid {
  display: grid;
  grid-template-columns: repeat(5, 1fr);
  gap: var(--space-6);
  max-width: 1400px;
  margin: 0 auto;
}

#tutorCards > * {
  display: none;
}

.tutor-card-modern {
  display: block;
  text-decoration: none;
  color: inherit;
  transition:
    opacity 0.3s cubic-bezier(0.455, 0.03, 0.515, 0.955),
    transform 0.3s cubic-bezier(0.455, 0.03, 0.515, 0.955);
  opacity: 1;
  transform: scale(1);
}
.tutor-card-modern:focus {
  outline: 3px solid var(--primary-500);
  border-radius: var(--radius-2xl);
}
.tutor-card-modern.shuffling {
  opacity: 0.4;
  transform: scale(0.98);
}

.tutor-card-inner {
  position: relative;
  background: white;
  border-radius: var(--radius-2xl);
  overflow: hidden;
  box-shadow: var(--shadow-md);
  border: 1px solid var(--neutral-200);
  height: 100%;
  display: flex;
  flex-direction: column;
  transition: all var(--transition-slow);
}
.tutor-card-modern:hover .tutor-card-inner {
  transform: translateY(-8px);
  box-shadow: var(--shadow-2xl);
  border-color: var(--primary-300);
}

.tutor-image-wrapper {
  position: relative;
  width: 100%;
  padding-top: 100%;
  background: linear-gradient(
    135deg,
    var(--neutral-100) 0%,
    var(--neutral-200) 100%
  );
  overflow: hidden;
}
.tutor-image {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  object-fit: cover;
  object-position: center top;
  transition: transform var(--transition-slower);
}
.tutor-card-modern:hover .tutor-image {
  transform: scale(1.08);
}

.tutor-image-overlay {
  position: absolute;
  inset: 0;
  background: linear-gradient(to top, rgba(0, 0, 0, 0.8) 0%, transparent 60%);
  display: flex;
  align-items: flex-end;
  justify-content: center;
  padding: var(--space-6);
  opacity: 0;
  transition: opacity var(--transition-base);
}
.tutor-card-modern:hover .tutor-image-overlay {
  opacity: 1;
}

.overlay-content {
  display: flex;
  align-items: center;
  gap: 6px;
  padding: 6px 14px;
  background: white;
  border-radius: var(--radius-full);
  color: var(--neutral-900);
  font-weight: 600;
  font-size: 0.85rem;
  white-space: nowrap;
  transform: translateY(10px);
  transition: transform var(--transition-base);
}

.tutor-card-modern:hover .overlay-content {
  transform: translateY(0);
}

.tutor-details {
  padding: var(--space-5);
  flex: 1;
  display: flex;
  flex-direction: column;
  gap: var(--space-3);
  min-height: 172px;
}
.tutor-name-modern {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: var(--neutral-900);
  margin: 0;
  transition: color var(--transition-base);
}
.tutor-card-modern:hover .tutor-name-modern {
  color: var(--primary-600);
}

.tutor-education {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
  min-height: 64px;
}
.education-item {
  display: flex;
  align-items: flex-start;
  gap: var(--space-2);
  font-size: 0.875rem;
}
.education-item i {
  color: var(--primary-600);
  font-size: 0.875rem;
  margin-top: 2px;
  flex-shrink: 0;
}
.education-text {
  color: var(--neutral-600);
  display: -webkit-box;
  -webkit-line-clamp: 2;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.tutor-rating-container {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding-top: var(--space-3);
  border-top: 1px solid var(--neutral-200);
  margin-top: auto;
}
.rating-stars {
  display: flex;
  gap: 2px;
}
.rating-stars i {
  font-size: 0.875rem;
  transition: transform var(--transition-fast);
}
.tutor-card-modern:hover .rating-stars i {
  transform: scale(1.1);
}
.star-standard {
  color: var(--primary-500);
}
.star-premium {
  color: #dc2626;
}
.rating-text {
  font-size: 0.875rem;
  font-weight: 700;
  color: var(--neutral-700);
}

/* Empty State */
.empty-state-modern {
  grid-column: 1 / -1;
  text-align: center;
  padding: var(--space-20) var(--space-4);
}
.empty-icon {
  width: 120px;
  height: 120px;
  margin: 0 auto var(--space-6);
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--neutral-100);
  border-radius: var(--radius-full);
}
.empty-icon i {
  font-size: 3rem;
  color: var(--neutral-400);
}
.empty-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--neutral-700);
  margin: 0 0 var(--space-2) 0;
}
.empty-text {
  font-size: 1rem;
  color: var(--neutral-500);
  margin: 0;
}

/* ==========================================================================
   4. MODERN SUBJECT CARDS (UPDATED: FIXED WHITE SPACE ISSUE)
   ========================================================================== */
.subjects-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: var(--space-3);
  max-width: 1400px;
  margin: 0 auto;
  /* [แก้ไข] เปลี่ยนจาก stretch เป็น flex-start เพื่อไม่ให้การ์ดข้างๆ ยืดตามจนเกิดพื้นที่ขาว */
  align-items: flex-start;
}

.subject-category-card {
  background: white;
  border-radius: var(--radius-sm);
  box-shadow: var(--shadow-md);
  border: 1px solid var(--neutral-200);
  overflow: hidden;
  transition: all var(--transition-slow);

  /* [แก้ไข] ใช้ Flexbox + Min Height แทน Height 100% */
  display: flex;
  flex-direction: column;
  height: auto; /* ให้สูงตามเนื้อหาจริงเมื่อกดดูเพิ่มเติม */
  min-height: 450px; /* ความสูงมาตรฐานเริ่มต้น เพื่อให้การ์ดดูเท่ากันตอนแรก */
}

/* .subject-category-card:hover { transform: translateY(-4px); box-shadow: var(--shadow-xl); border-color: var(--primary-300); } */

.category-header {
  background: var(--gradient-dark);
  padding: var(--space-3);
  display: flex;
  align-items: center;
  gap: var(--space-3);
  position: relative;
  overflow: hidden;
  flex-shrink: 0;
}
.category-header::before {
  content: "";
  position: absolute;
  top: -50%;
  right: -50%;
  width: 200%;
  height: 200%;
  background: radial-gradient(
    circle,
    rgba(251, 191, 36, 0.1) 0%,
    transparent 70%
  );
  transition: transform var(--transition-slower);
}
.subject-category-card:hover .category-header::before {
  transform: translate(-25%, -25%);
}
.category-title {
  margin: 0;
  flex: 1;
  position: relative;
  z-index: 1;
}
.category-link {
  font-family: var(--font-heading);
  font-size: 1.1rem;
  font-weight: 700;
  color: white;
  text-decoration: none;
  display: block;
}
.category-link:hover {
  color: var(--primary-300);
}

.category-body {
  padding: var(--space-2);
  /* [แก้ไข] ให้ส่วนเนื้อหายืดเต็มพื้นที่ที่เหลือของ Min-Height */
  flex: 1;
  display: flex;
  flex-direction: column;
}

.subjects-list {
  list-style: none;
  padding: 0;
  margin: 0 0 var(--space-2) 0;
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}
.subject-list-item {
  transition: transform var(--transition-fast);
}
.subject-list-item:hover {
  transform: translateX(4px);
}

.subject-link-modern {
  display: flex;
  align-items: center;
  gap: var(--space-3);
  padding: var(--space-3) var(--space-4);
  border-radius: var(--radius-md);
  text-decoration: none;
  transition: all var(--transition-base);
  position: relative;
  overflow: hidden;
}
.subject-link-modern::before {
  content: "";
  position: absolute;
  left: 0;
  top: 0;
  bottom: 0;
  width: 3px;
  background: var(--gradient-primary);
  transform: scaleY(0);
  transition: transform var(--transition-base);
}
.subject-link-modern:hover {
  background: var(--primary-50);
}
.subject-link-modern:hover::before {
  transform: scaleY(1);
}
.subject-bullet {
  width: 6px;
  height: 6px;
  background: var(--primary-500);
  border-radius: var(--radius-full);
  flex-shrink: 0;
  transition: transform var(--transition-base);
}
.subject-link-modern:hover .subject-bullet {
  transform: scale(1.5);
}
.subject-name {
  flex: 1;
  font-size: 0.9rem;
  color: var(--neutral-700);
  font-weight: 500;
  transition: color var(--transition-base);
}
.subject-link-modern:hover .subject-name {
  color: var(--primary-700);
  font-weight: 600;
}
.subject-arrow {
  font-size: 0.875rem;
  color: var(--neutral-400);
  opacity: 0;
  transform: translateX(-8px);
  transition: all var(--transition-base);
}
.subject-link-modern:hover .subject-arrow {
  opacity: 1;
  transform: translateX(0);
  color: var(--primary-600);
}

.expand-button {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  background: var(--neutral-100);
  border: 2px solid var(--neutral-200);
  border-radius: var(--radius-md);
  cursor: pointer;
  transition: all var(--transition-base);
  font-weight: 600;
  color: var(--neutral-700);
  display: flex;
  align-items: center;
  justify-content: center;

  /* [แก้ไข] ดันปุ่มลงล่างสุดเสมอ */
  margin-top: auto;
}
.expand-button:hover {
  background: var(--primary-50);
  border-color: var(--primary-300);
  color: var(--primary-700);
}
.expand-button:active {
  transform: scale(0.98);
}
.expand-button.expanded {
  background: var(--primary-500);
  border-color: var(--primary-600);
  color: white;
}
.expand-button.expanded:hover {
  background: var(--primary-600);
  border-color: var(--primary-700);
}
.expand-text,
.collapse-text {
  display: flex;
  align-items: center;
  gap: var(--space-2);
  font-size: 0.875rem;
}

/* ==========================================================================
   5. RESPONSIVE DESIGN
   ========================================================================== */
@media (min-width: 1400px) {
  .container {
    max-width: 1320px;
  }
  .tutors-grid {
    grid-template-columns: repeat(5, 1fr);
  }
}
@media (max-width: 1199px) {
  .tutors-grid {
    grid-template-columns: repeat(4, 1fr);
    gap: var(--space-5);
  }
  .subjects-grid {
    grid-template-columns: repeat(auto-fit, minmax(260px, 1fr));
  }
}
@media (max-width: 991px) {
  .premium-section {
    padding: var(--space-16) 0;
  }
  .info-bar-item,
  .subject-header-title {
    font-size: 1.4rem !important;
  }
  .tutors-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-4);
  }
  .subjects-grid {
    grid-template-columns: repeat(auto-fit, minmax(240px, 1fr));
    gap: var(--space-3);
  }
}
@media (max-width: 768px) {
  .hero-section {
    height: 320px !important;
    padding-top: 0 !important;
  }
  .hero-slide,
  #heroSlider,
  #heroSliderMini {
    background-size: cover !important;
    background-repeat: no-repeat !important;
    background-position: center !important;
    width: 100% !important;
    height: 100% !important;
    top: 0 !important;
    left: 0 !important;
    padding-top: 0 !important;
  }
  .hero-content {
    width: 90%;
  }
  .hero-title {
    font-size: clamp(1.6rem, 5vw, 2.2rem) !important;
    line-height: 1.3 !important;
  }
  .hero-subtitle,
  .hero-description {
    font-size: 0.95rem !important;
  }
  .info-bar,
  .subject-header-bar {
    padding: 15px 0 !important;
  }
  .info-bar-item,
  .subject-header-title {
    font-size: 1.1rem !important;
  }
  .premium-section {
    padding: var(--space-12) 0;
  }
  .tutors-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-3);
  }
  .subjects-grid {
    grid-template-columns: repeat(3, 1fr);
    gap: var(--space-3);
  }
  .tutor-details {
    padding: var(--space-3);
    min-height: 150px;
  }
  .tutor-name-modern {
    font-size: 1rem;
  }
}
@media (max-width: 576px) {
  .premium-section {
    padding: var(--space-10) 0;
  }
  .tutors-grid,
  .subjects-grid {
    grid-template-columns: repeat(2, 1fr);
    gap: var(--space-2);
  }

  .tutor-card-inner {
    border-radius: var(--radius-lg);
  }
  .tutor-details {
    padding: var(--space-2);
    gap: var(--space-1);
    min-height: 132px;
  }
  .tutor-education {
    min-height: 52px;
  }
  .tutor-name-modern {
    font-size: 0.85rem;
  }
  .education-item {
    font-size: 0.7rem;
  }

  .category-header {
    padding: var(--space-3);
  }
  .category-link {
    font-size: 0.95rem;
  }
  .category-body {
    padding: var(--space-3);
  }
  .subject-link-modern {
    padding: var(--space-1) var(--space-2);
  }
  .subject-name {
    font-size: 0.8rem;
  }
  .expand-button {
    padding: var(--space-2);
    font-size: 0.75rem;
  }

  .rating-stars i {
    font-size: 0.7rem;
  }
  .rating-text {
    font-size: 0.7rem;
  }

  /* [แก้ไข] ปรับ min-height ให้น้อยลงสำหรับมือถือ */
  .subject-category-card {
    min-height: 350px;
  }
}
@media (max-width: 400px) {
  .rating-stars i {
    font-size: 0.6rem;
  }
}

/* ==========================================================================
   NAVIGATION BUTTONS
   ========================================================================== */
.slider-nav {
  position: absolute;
  top: 50%;
  transform: translateY(-50%);
  width: 50px;
  height: 50px;
  background: rgba(0, 0, 0, 0.3);
  color: white;
  border: 2px solid rgba(255, 255, 255, 0.3);
  border-radius: 50%;
  cursor: pointer;
  z-index: 20;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 1.2rem;
  transition: all var(--transition-base);
  backdrop-filter: blur(2px);
}

.slider-nav:hover {
  background: var(--primary-500);
  border-color: var(--primary-500);
  transform: translateY(-50%) scale(1.1);
  box-shadow: 0 0 15px rgba(245, 158, 11, 0.5);
}

.slider-nav.prev {
  left: 30px;
}

.slider-nav.next {
  right: 30px;
}

@media (max-width: 768px) {
  .slider-nav {
    width: 40px;
    height: 40px;
    font-size: 1rem;
    background: rgba(0, 0, 0, 0.1);
    border: none;
  }

  .slider-nav.prev {
    left: 10px;
  }
  .slider-nav.next {
    right: 10px;
  }
}