/* ==========================================================================
   Ankit Roy — Learning Plan & Curated AI Courses Stylesheet
   Color Harmonized with Main Portfolio: Deep Teal, Warm Gold, Vibrant Green
   ========================================================================== */

:root,
[data-theme="dark"] {
  --font-sans: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
  --font-mono: ui-monospace, SFMono-Regular, Menlo, Monaco, Consolas, monospace;

  /* Default Dark Theme: Inverted Deep Teal & Warm Gold Palette */
  --bg-page: #1a313a;                  /* Dark Deep Teal */
  --bg-card: #264653;                  /* Deep Teal Cards */
  --bg-card-hover: #2c4f5d;
  --bg-subtle: #1e3742;
  --text-main: #FFFFFF;                /* White Accent */
  --text-muted: #d5e0e5;               /* Soft Icy White-Teal */
  --text-faint: #E9C46A;               /* Warm Gold */
  --border: rgba(233, 196, 106, 0.25);
  --border-hover: #E9C46A;
  --shadow-sm: 0 2px 6px rgba(0, 0, 0, 0.3);
  --shadow-md: 0 6px 20px rgba(0, 0, 0, 0.4);
  --shadow-lg: 0 12px 34px rgba(0, 0, 0, 0.5);

  --primary: #E9C46A;                  /* Warm Gold */
  --primary-hover: #f3d485;
  --primary-light: rgba(233, 196, 106, 0.15);
  --primary-gradient: linear-gradient(135deg, #2A9D8F 0%, #E9C46A 100%);
  --secondary: #2A9D8F;                /* Vibrant Green */
  --secondary-hover: #3bc5b5;
  --secondary-light: rgba(42, 157, 143, 0.2);
  --accent: #FFFFFF;
  --accent-gold: #E9C46A;
  --badge-glow: rgba(233, 196, 106, 0.3);

  --nav-bg: rgba(38, 70, 83, 0.92);
  --nav-border: rgba(233, 196, 106, 0.25);
  --nav-shadow: 0 4px 20px -2px rgba(0, 0, 0, 0.35);
  --nav-link-hover-bg: rgba(233, 196, 106, 0.15);

  /* Categories */
  --tag-genai-bg: rgba(42, 157, 143, 0.2);
  --tag-genai-border: rgba(42, 157, 143, 0.45);
  --tag-genai-text: #6ee7b7;

  --tag-prompt-bg: rgba(233, 196, 106, 0.15);
  --tag-prompt-border: rgba(233, 196, 106, 0.35);
  --tag-prompt-text: #E9C46A;

  --tag-aiml-bg: rgba(59, 130, 246, 0.2);
  --tag-aiml-border: rgba(59, 130, 246, 0.4);
  --tag-aiml-text: #93c5fd;

  --tag-llm-bg: rgba(168, 85, 247, 0.2);
  --tag-llm-border: rgba(168, 85, 247, 0.4);
  --tag-llm-text: #d8b4fe;
}

[data-theme="gold"],
[data-theme="light"] {
  /* Warm Gold Light Palette */
  --bg-page: #E9C46A;                  /* Warm Gold Background */
  --bg-card: #FFFFFF;                  /* White Accent Cards */
  --bg-card-hover: #FFFFFF;
  --bg-subtle: #F6F8F9;
  --text-main: #264653;                /* Deep Teal Text */
  --text-muted: #3d5f6d;               /* Soft Deep Teal */
  --text-faint: #607d8b;
  --border: rgba(38, 70, 83, 0.15);
  --border-hover: #264653;
  --shadow-sm: 0 2px 6px rgba(38, 70, 83, 0.08);
  --shadow-md: 0 6px 18px rgba(38, 70, 83, 0.12);
  --shadow-lg: 0 12px 32px rgba(38, 70, 83, 0.16);

  --primary: #264653;                  /* Deep Teal */
  --primary-hover: #1d353f;
  --primary-light: rgba(38, 70, 83, 0.09);
  --primary-gradient: linear-gradient(135deg, #264653 0%, #2A9D8F 100%);
  --secondary: #2A9D8F;                /* Vibrant Green */
  --secondary-hover: #21867a;
  --secondary-light: rgba(42, 157, 143, 0.12);
  --accent: #FFFFFF;                   /* White Accent */
  --accent-gold: #E9C46A;              /* Warm Gold */
  --badge-glow: rgba(38, 70, 83, 0.2);

  --nav-bg: rgba(255, 255, 255, 0.94);
  --nav-border: rgba(38, 70, 83, 0.15);
  --nav-shadow: 0 4px 20px -2px rgba(38, 70, 83, 0.12);
  --nav-link-hover-bg: rgba(38, 70, 83, 0.08);

  --tag-genai-bg: rgba(42, 157, 143, 0.12);
  --tag-genai-border: rgba(42, 157, 143, 0.35);
  --tag-genai-text: #21867a;

  --tag-prompt-bg: rgba(233, 196, 106, 0.25);
  --tag-prompt-border: rgba(233, 196, 106, 0.6);
  --tag-prompt-text: #264653;

  --tag-aiml-bg: rgba(38, 70, 83, 0.08);
  --tag-aiml-border: rgba(38, 70, 83, 0.25);
  --tag-aiml-text: #264653;

  --tag-llm-bg: rgba(42, 157, 143, 0.12);
  --tag-llm-border: rgba(42, 157, 143, 0.35);
  --tag-llm-text: #21867a;
}

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

html {
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  background-color: var(--bg-page);
  background-image: 
    radial-gradient(at 0% 0%, rgba(42, 157, 143, 0.16) 0px, transparent 50%),
    radial-gradient(at 100% 10%, rgba(38, 70, 83, 0.1) 0px, transparent 50%),
    radial-gradient(at 50% 90%, rgba(255, 255, 255, 0.18) 0px, transparent 50%);
  background-attachment: fixed;
  color: var(--text-main);
  line-height: 1.65;
  font-size: 1rem;
  letter-spacing: -0.012em;
  transition: background-color 0.25s ease, color 0.25s ease;
  min-height: 100vh;
}

/* Site Wrapper */
.site-wrapper {
  max-width: 1200px;
  margin: 0 auto;
  padding: 2.75rem 2rem 5.5rem;
}

/* Top Navigation */
.top-nav {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding: 0.65rem 1.35rem;
  background-color: var(--nav-bg);
  border: 1px solid var(--nav-border);
  border-radius: 9999px;
  box-shadow: var(--nav-shadow);
  margin-bottom: 2.5rem;
  position: sticky;
  top: 1rem;
  z-index: 50;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  transition: all 0.2s ease;
}

.brand-mark {
  font-size: 0.925rem;
  font-weight: 750;
  letter-spacing: -0.02em;
  color: var(--text-main);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 0.6rem;
}

.brand-badge {
  background: var(--primary-gradient);
  color: #ffffff;
  padding: 0.18rem 0.65rem;
  border-radius: 9999px;
  font-size: 0.725rem;
  font-weight: 650;
  letter-spacing: 0.02em;
  box-shadow: 0 2px 8px rgba(38, 70, 83, 0.25);
}

.nav-controls {
  display: flex;
  align-items: center;
  gap: 1rem;
}

.btn-back-portfolio {
  color: var(--text-main);
  text-decoration: none;
  font-size: 0.85rem;
  font-weight: 650;
  padding: 0.4rem 0.9rem;
  border-radius: 9999px;
  background-color: var(--bg-subtle);
  border: 1px solid var(--border);
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  transition: all 0.2s ease;
}

.btn-back-portfolio:hover {
  border-color: var(--primary);
  color: var(--primary);
  transform: translateX(-2px);
}

.theme-toggle {
  background: var(--bg-subtle);
  border: 1px solid var(--border);
  border-radius: 50%;
  width: 36px;
  height: 36px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  color: var(--text-muted);
  transition: all 0.2s cubic-bezier(0.16, 1, 0.3, 1);
}

.theme-toggle:hover {
  color: var(--primary);
  border-color: var(--primary);
  transform: rotate(20deg) scale(1.05);
}

.theme-toggle svg {
  width: 18px;
  height: 18px;
}

/* Page Header */
.hub-header {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 2.25rem 2.5rem;
  box-shadow: var(--shadow-md);
  margin-bottom: 2rem;
  position: relative;
  overflow: hidden;
}

.hub-eyebrow {
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  font-size: 0.75rem;
  font-weight: 750;
  text-transform: uppercase;
  letter-spacing: 0.08em;
  color: var(--secondary);
  background-color: var(--secondary-light);
  padding: 0.25rem 0.65rem;
  border-radius: 6px;
  margin-bottom: 0.75rem;
}

.hub-title {
  font-size: 2rem;
  font-weight: 800;
  letter-spacing: -0.03em;
  color: var(--text-main);
  line-height: 1.2;
  margin-bottom: 0.65rem;
}

.hub-desc {
  font-size: 0.985rem;
  color: var(--text-muted);
  line-height: 1.65;
  max-width: 820px;
}

/* Search & Filter Control Center */
.control-center {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 16px;
  padding: 1.5rem;
  box-shadow: var(--shadow-sm);
  margin-bottom: 2rem;
  display: flex;
  flex-direction: column;
  gap: 1.25rem;
}

/* Search Bar */
.search-wrapper {
  position: relative;
  width: 100%;
}

.search-icon {
  position: absolute;
  left: 1rem;
  top: 50%;
  transform: translateY(-50%);
  width: 20px;
  height: 20px;
  color: var(--text-faint);
  pointer-events: none;
}

.search-input {
  width: 100%;
  padding: 0.85rem 2.8rem 0.85rem 2.85rem;
  font-size: 0.95rem;
  font-family: var(--font-sans);
  background-color: var(--bg-subtle);
  color: var(--text-main);
  border: 1px solid var(--border);
  border-radius: 12px;
  outline: none;
  transition: all 0.2s ease;
}

.search-input:focus {
  border-color: var(--secondary);
  box-shadow: 0 0 0 3px var(--secondary-light);
  background-color: var(--bg-card);
}

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

.search-clear-btn {
  position: absolute;
  right: 0.85rem;
  top: 50%;
  transform: translateY(-50%);
  background: none;
  border: none;
  color: var(--text-faint);
  cursor: pointer;
  padding: 0.25rem;
  border-radius: 50%;
  display: none;
  align-items: center;
  justify-content: center;
}

.search-clear-btn:hover {
  color: var(--text-main);
}

.search-clear-btn svg {
  width: 16px;
  height: 16px;
}

/* Category Filters */
.filter-tabs {
  display: flex;
  flex-wrap: wrap;
  gap: 0.5rem;
}

.filter-tab {
  background-color: var(--bg-subtle);
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.85rem;
  font-weight: 600;
  padding: 0.45rem 0.95rem;
  border-radius: 9999px;
  cursor: pointer;
  display: inline-flex;
  align-items: center;
  gap: 0.45rem;
  transition: all 0.18s ease;
}

.filter-tab:hover {
  color: var(--text-main);
  border-color: var(--secondary);
  transform: translateY(-1px);
}

.filter-tab.active {
  background: var(--primary-gradient);
  color: #ffffff;
  border-color: transparent;
  box-shadow: 0 3px 10px rgba(38, 70, 83, 0.25);
}

.tab-count {
  font-size: 0.75rem;
  padding: 0.1rem 0.45rem;
  border-radius: 9999px;
  background-color: rgba(0, 0, 0, 0.15);
  color: inherit;
}

.filter-tab.active .tab-count {
  background-color: rgba(255, 255, 255, 0.25);
}

/* Provider Chips */
.provider-row {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
  padding-top: 0.85rem;
  border-top: 1px dashed var(--border);
}

.provider-label {
  font-size: 0.75rem;
  font-weight: 750;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  color: var(--text-faint);
  margin-right: 0.35rem;
}

.provider-chip {
  background: none;
  border: 1px solid var(--border);
  color: var(--text-muted);
  font-size: 0.785rem;
  font-weight: 550;
  padding: 0.25rem 0.65rem;
  border-radius: 6px;
  cursor: pointer;
  transition: all 0.15s ease;
}

.provider-chip:hover {
  color: var(--primary);
  border-color: var(--primary);
}

.provider-chip.active {
  background-color: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
  font-weight: 650;
}

/* Results Info Bar */
.results-bar {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.25rem;
  padding: 0 0.25rem;
}

.results-count {
  font-size: 0.885rem;
  font-weight: 600;
  color: var(--text-muted);
}

.results-count span {
  color: var(--primary);
  font-weight: 750;
}

.btn-reset-filters {
  background: none;
  border: none;
  color: var(--secondary);
  font-size: 0.825rem;
  font-weight: 650;
  cursor: pointer;
  display: none;
  align-items: center;
  gap: 0.3rem;
  text-decoration: underline;
}

.btn-reset-filters:hover {
  color: var(--primary);
}

/* Course Cards Grid */
.courses-grid {
  display: grid;
  grid-template-columns: repeat(auto-fill, minmax(330px, 1fr));
  gap: 1.25rem;
}

@media (min-width: 768px) {
  .courses-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

.course-card {
  background-color: var(--bg-card);
  border: 1px solid var(--border);
  border-radius: 14px;
  padding: 1.35rem 1.4rem;
  box-shadow: var(--shadow-sm);
  display: flex;
  flex-direction: column;
  justify-content: space-between;
  gap: 1rem;
  transition: transform 0.2s cubic-bezier(0.16, 1, 0.3, 1), box-shadow 0.2s ease, border-color 0.2s ease;
  position: relative;
}

.course-card:hover {
  transform: translateY(-3px);
  box-shadow: var(--shadow-md);
  border-color: var(--secondary);
}

.card-top {
  display: flex;
  align-items: flex-start;
  gap: 1rem;
}

.provider-logo-box {
  width: 52px;
  height: 52px;
  border-radius: 10px;
  background-color: #ffffff;
  border: 1px solid var(--border);
  padding: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  flex-shrink: 0;
  box-shadow: 0 2px 6px rgba(0, 0, 0, 0.05);
}

.provider-logo-box img {
  max-width: 100%;
  max-height: 100%;
  object-fit: contain;
}

.card-meta-wrap {
  display: flex;
  flex-direction: column;
  gap: 0.25rem;
  flex: 1;
}

.card-tags {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 0.4rem;
}

.badge-cat {
  font-size: 0.725rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  padding: 0.15rem 0.55rem;
  border-radius: 4px;
}

.badge-cat.genai {
  background-color: var(--tag-genai-bg);
  border: 1px solid var(--tag-genai-border);
  color: var(--tag-genai-text);
}

.badge-cat.prompt {
  background-color: var(--tag-prompt-bg);
  border: 1px solid var(--tag-prompt-border);
  color: var(--tag-prompt-text);
}

.badge-cat.aiml {
  background-color: var(--tag-aiml-bg);
  border: 1px solid var(--tag-aiml-border);
  color: var(--tag-aiml-text);
}

.badge-cat.llm {
  background-color: var(--tag-llm-bg);
  border: 1px solid var(--tag-llm-border);
  color: var(--tag-llm-text);
}

.provider-name {
  font-size: 0.775rem;
  font-weight: 600;
  color: var(--text-faint);
}

.course-title {
  font-size: 1.05rem;
  font-weight: 750;
  color: var(--text-main);
  line-height: 1.35;
  letter-spacing: -0.015em;
  margin-top: 0.15rem;
}

.course-title a {
  color: inherit;
  text-decoration: none;
  transition: color 0.15s ease;
}

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

.course-desc {
  font-size: 0.885rem;
  color: var(--text-muted);
  line-height: 1.55;
  margin-top: 0.5rem;
  display: -webkit-box;
  -webkit-line-clamp: 3;
  -webkit-box-orient: vertical;
  overflow: hidden;
}

.card-footer {
  display: flex;
  justify-content: space-between;
  align-items: center;
  padding-top: 0.95rem;
  border-top: 1px dashed var(--border);
  margin-top: auto;
}

.badge-free {
  display: inline-flex;
  align-items: center;
  gap: 0.3rem;
  font-size: 0.75rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.04em;
  color: #2A9D8F;
  background-color: rgba(42, 157, 143, 0.12);
  padding: 0.2rem 0.55rem;
  border-radius: 4px;
}

[data-theme="dark"] .badge-free {
  color: #6ee7b7;
  background-color: rgba(42, 157, 143, 0.25);
}

.badge-free svg {
  width: 12px;
  height: 12px;
}

.btn-open-course {
  background: var(--primary-gradient);
  color: #ffffff;
  text-decoration: none;
  font-size: 0.825rem;
  font-weight: 650;
  padding: 0.45rem 0.95rem;
  border-radius: 8px;
  display: inline-flex;
  align-items: center;
  gap: 0.4rem;
  box-shadow: 0 2px 8px rgba(38, 70, 83, 0.2);
  transition: all 0.2s ease;
}

.btn-open-course:hover {
  transform: translateY(-2px);
  box-shadow: 0 4px 14px rgba(42, 157, 143, 0.35);
  color: #ffffff;
}

.btn-open-course svg {
  width: 13px;
  height: 13px;
  transition: transform 0.2s ease;
}

.btn-open-course:hover svg {
  transform: translateX(2px) translateY(-2px);
}

/* Empty State */
.empty-state {
  background-color: var(--bg-card);
  border: 1px dashed var(--border);
  border-radius: 16px;
  padding: 3.5rem 2rem;
  text-align: center;
  display: none;
  flex-direction: column;
  align-items: center;
  gap: 1rem;
  grid-column: 1 / -1;
}

.empty-icon {
  font-size: 2.5rem;
}

.empty-title {
  font-size: 1.25rem;
  font-weight: 750;
  color: var(--text-main);
}

.empty-desc {
  font-size: 0.925rem;
  color: var(--text-muted);
  max-width: 420px;
}

.btn-clear-empty {
  background: var(--primary-gradient);
  color: #ffffff;
  border: none;
  padding: 0.6rem 1.25rem;
  border-radius: 8px;
  font-weight: 650;
  font-size: 0.875rem;
  cursor: pointer;
  margin-top: 0.5rem;
  transition: all 0.2s ease;
}

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

/* Footer */
footer {
  margin-top: 4rem;
  padding-top: 2rem;
  border-top: 1px solid var(--border);
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 1rem;
  font-size: 0.85rem;
  color: var(--text-muted);
}

footer a {
  color: var(--primary);
  text-decoration: none;
  font-weight: 600;
}

footer a:hover {
  text-decoration: underline;
}

/* Responsive */
@media (max-width: 640px) {
  .site-wrapper {
    padding: 1.5rem 1rem 3.5rem;
  }

  .top-nav {
    padding: 0.5rem 1rem;
  }

  .hub-header {
    padding: 1.5rem 1.25rem;
  }

  .hub-title {
    font-size: 1.6rem;
  }

  .control-center {
    padding: 1.15rem;
  }

  .courses-grid {
    grid-template-columns: 1fr;
  }
}