/* ==========================================================================
   Mobile App UI/UX Case Study Stylesheet
   Strictly styled to match the reference case study layout
   Author: Deepak Raj Dandu Portfolio
   ========================================================================== */

:root, [data-theme="light"] {
  --cs-bg: #ffffff;
  --cs-canvas: #fafbff;
  --cs-heading: #0f172a;
  --cs-txt-bold: #1e1b4b;
  --cs-body: #475569;
  --cs-muted: #64748b;
  --cs-pur: #6021df;
  --cs-pur-dark: #4f17c5;
  --cs-pur-light: #7c3aed;
  --cs-card-bg: #f8faff;
  --cs-card-bdr: #e0e7ff;
  --cs-flow-bg: #f5f3ff;
  --cs-flow-bdr: #ddd6fe;
  --cs-flow-txt: #5b21b6;
  --cs-sep: #94a3b8;
  --cs-top-bg: rgba(255, 255, 255, 0.88);
  --cs-top-bdr: rgba(224, 231, 255, 0.8);
}

[data-theme="dark"] {
  --cs-bg: #090a10;
  --cs-canvas: #0c0e17;
  --cs-heading: #f8fafc;
  --cs-txt-bold: #e0e7ff;
  --cs-body: #94a3b8;
  --cs-muted: #64748b;
  --cs-pur: #7c3aed;
  --cs-pur-dark: #6366f1;
  --cs-pur-light: #a78bfa;
  --cs-card-bg: rgba(255, 255, 255, 0.035);
  --cs-card-bdr: rgba(124, 58, 237, 0.22);
  --cs-flow-bg: rgba(124, 58, 237, 0.12);
  --cs-flow-bdr: rgba(124, 58, 237, 0.3);
  --cs-flow-txt: #c4b5fd;
  --cs-sep: #475569;
  --cs-top-bg: rgba(9, 10, 16, 0.85);
  --cs-top-bdr: rgba(255, 255, 255, 0.08);
}

.cs-page-wrap {
  background: var(--cs-bg);
  min-height: 100vh;
  color: var(--cs-body);
  font-family: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, sans-serif;
  -webkit-font-smoothing: antialiased;
}

/* Top Navigation Bar */
.cs-nav-bar {
  position: sticky;
  top: 0;
  z-index: 100;
  background: var(--cs-top-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--cs-top-bdr);
  padding: 12px 24px;
}

.cs-nav-inner {
  max-width: 900px;
  margin: 0 auto;
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
}

.cs-nav-left {
  display: flex;
  align-items: center;
  gap: 16px;
}

.cs-back-link {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  color: var(--cs-heading);
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 600;
  padding: 6px 14px;
  border-radius: 100px;
  border: 1px solid var(--cs-card-bdr);
  background: var(--cs-card-bg);
  transition: all 0.2s ease;
}

.cs-back-link:hover {
  border-color: var(--cs-pur);
  color: var(--cs-pur);
  transform: translateX(-2px);
}

.cs-nav-brand {
  font-size: 14px;
  font-weight: 800;
  color: var(--cs-heading);
  text-decoration: none;
  display: flex;
  align-items: center;
  gap: 8px;
}

.cs-nav-brand span {
  width: 8px;
  height: 8px;
  background: var(--cs-pur);
  border-radius: 50%;
  box-shadow: 0 0 10px var(--cs-pur);
}

.cs-nav-actions {
  display: flex;
  align-items: center;
  gap: 12px;
}

.cs-theme-btn {
  background: var(--cs-card-bg);
  border: 1px solid var(--cs-card-bdr);
  color: var(--cs-heading);
  width: 38px;
  height: 38px;
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  cursor: pointer;
  transition: all 0.2s;
}

.cs-theme-btn:hover {
  border-color: var(--cs-pur);
  color: var(--cs-pur);
}

/* App Switcher Tabs Pill Bar */
.cs-app-switcher {
  max-width: 900px;
  margin: 20px auto 0;
  padding: 0 24px;
}

.cs-switcher-pills {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow-x: auto;
  padding: 8px 12px;
  background: var(--cs-card-bg);
  border: 1px solid var(--cs-card-bdr);
  border-radius: 100px;
  scrollbar-width: none;
}

.cs-switcher-pills::-webkit-scrollbar {
  display: none;
}

.cs-switch-pill {
  font-size: 12px;
  font-weight: 600;
  color: var(--cs-muted);
  text-decoration: none;
  padding: 6px 14px;
  border-radius: 100px;
  white-space: nowrap;
  transition: all 0.2s;
}

.cs-switch-pill:hover {
  color: var(--cs-heading);
  background: rgba(124, 58, 237, 0.08);
}

.cs-switch-pill.active {
  background: var(--cs-pur);
  color: #ffffff !important;
  box-shadow: 0 4px 12px rgba(96, 33, 223, 0.35);
}

/* Main Container */
.cs-container {
  max-width: 660px;
  margin: 0 auto;
  padding: 50px 24px 80px;
}

/* Case Study Header */
.cs-eyebrow {
  font-size: 11.5px;
  font-weight: 700;
  letter-spacing: 1.8px;
  color: var(--cs-pur-light);
  text-transform: uppercase;
  margin-bottom: 14px;
  display: block;
}

.cs-title {
  font-size: clamp(34px, 5.2vw, 46px);
  font-weight: 800;
  color: var(--cs-heading);
  line-height: 1.16;
  letter-spacing: -1px;
  margin: 0 0 16px 0;
}

.cs-subtitle {
  font-size: 16px;
  color: var(--cs-muted);
  line-height: 1.65;
  margin: 0 0 28px 0;
  font-weight: 400;
}

/* Primary Action Button */
.cs-btn-figma {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 10px;
  background: var(--cs-pur);
  color: #ffffff !important;
  padding: 13px 28px;
  border-radius: 9999px;
  font-size: 14.5px;
  font-weight: 600;
  text-decoration: none;
  box-shadow: 0 10px 24px -4px rgba(96, 33, 223, 0.45);
  transition: all 0.25s cubic-bezier(0.16, 1, 0.3, 1);
  margin-bottom: 44px;
}

.cs-btn-figma:hover {
  transform: translateY(-2px);
  background: var(--cs-pur-dark);
  box-shadow: 0 14px 30px -4px rgba(96, 33, 223, 0.55);
}

.cs-btn-figma svg {
  width: 16px;
  height: 16px;
  transition: transform 0.2s ease;
}

.cs-btn-figma:hover svg {
  transform: translateX(3px);
}

/* Common Section Heading */
.cs-sec-heading {
  font-size: 16px;
  font-weight: 700;
  color: var(--cs-heading);
  margin: 0 0 14px 0;
  display: flex;
  align-items: center;
  gap: 8px;
}

.cs-sec-heading .cs-icon-emoji {
  font-size: 17px;
  line-height: 1;
}

/* Section: Project Overview */
.cs-overview-grid {
  display: grid;
  grid-template-columns: repeat(4, 1fr);
  gap: 12px;
  margin-bottom: 40px;
}

.cs-overview-card {
  background: var(--cs-card-bg);
  border: 1px solid var(--cs-card-bdr);
  border-radius: 12px;
  padding: 14px 16px;
  display: flex;
  flex-direction: column;
  justify-content: center;
}

.cs-ov-label {
  font-size: 10px;
  font-weight: 800;
  letter-spacing: 0.8px;
  text-transform: uppercase;
  color: var(--cs-pur-light);
  margin-bottom: 6px;
}

.cs-ov-value {
  font-size: 13.5px;
  font-weight: 600;
  color: var(--cs-txt-bold);
  line-height: 1.35;
}

/* Section: Business Challenge */
.cs-challenge-text {
  font-size: 14.5px;
  color: var(--cs-body);
  line-height: 1.75;
  margin: 0 0 40px 0;
}

/* Section: Research & User Pain Points */
.cs-research-intro {
  font-size: 14.5px;
  color: var(--cs-body);
  line-height: 1.7;
  margin: 0 0 14px 0;
}

.cs-pain-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 12px;
  margin: 0 0 40px 0;
  padding: 0;
}

.cs-pain-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  font-size: 14px;
  color: var(--cs-body);
  line-height: 1.6;
}

.cs-pain-arrow {
  color: var(--cs-pur-light);
  font-weight: 700;
  font-size: 15px;
  flex-shrink: 0;
}

/* Section: User Flow */
.cs-flow-wrap {
  display: flex;
  flex-wrap: wrap;
  align-items: center;
  gap: 8px 10px;
  margin: 0 0 40px 0;
}

.cs-flow-step {
  background: var(--cs-flow-bg);
  border: 1px solid var(--cs-flow-bdr);
  border-radius: 10px;
  padding: 8px 14px;
  font-size: 13px;
  font-weight: 600;
  color: var(--cs-flow-txt);
  display: inline-flex;
  align-items: center;
}

.cs-flow-sep {
  color: var(--cs-sep);
  font-weight: 700;
  font-size: 14px;
  display: inline-flex;
  align-items: center;
}

/* Section: Design Decisions */
.cs-decisions-grid {
  display: grid;
  grid-template-columns: repeat(2, 1fr);
  gap: 14px;
  margin: 0 0 40px 0;
}

.cs-decision-card {
  background: var(--cs-card-bg);
  border: 1px solid var(--cs-card-bdr);
  border-radius: 14px;
  padding: 18px 20px;
}

.cs-decision-title {
  font-size: 14.5px;
  font-weight: 700;
  color: var(--cs-heading);
  margin: 0 0 8px 0;
}

.cs-decision-desc {
  font-size: 13px;
  color: var(--cs-muted);
  line-height: 1.65;
  margin: 0;
}

/* Section: Outcome */
.cs-outcome-grid {
  display: grid;
  grid-template-columns: repeat(3, 1fr);
  gap: 12px;
  margin: 0 0 50px 0;
}

.cs-outcome-card {
  background: var(--cs-pur);
  color: #ffffff;
  border-radius: 14px;
  padding: 24px 16px;
  text-align: center;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: flex-start;
  box-shadow: 0 10px 24px -4px rgba(96, 33, 223, 0.35);
}

.cs-outcome-val {
  font-size: 22px;
  font-weight: 800;
  color: #ffffff;
  margin-bottom: 10px;
  line-height: 1.2;
}

.cs-outcome-desc {
  font-size: 12px;
  color: rgba(255, 255, 255, 0.9);
  line-height: 1.5;
  margin: 0;
}

/* Section: Interactive Figma Prototype */
.cs-proto-wrap {
  margin-top: 50px;
  padding-top: 40px;
  border-top: 1px solid var(--cs-card-bdr);
}

.cs-proto-box {
  background: var(--cs-card-bg);
  border: 2px dashed var(--cs-card-bdr);
  border-radius: 20px;
  padding: 40px 24px;
  text-align: center;
  transition: border-color 0.2s ease;
}

.cs-proto-box:hover {
  border-color: var(--cs-pur-light);
}

.cs-proto-icon {
  width: 56px;
  height: 56px;
  border-radius: 16px;
  background: rgba(124, 58, 237, 0.12);
  color: var(--cs-pur);
  display: inline-flex;
  align-items: center;
  justify-content: center;
  margin-bottom: 16px;
}

.cs-proto-title {
  font-size: 18px;
  font-weight: 700;
  color: var(--cs-heading);
  margin-bottom: 8px;
}

.cs-proto-note {
  font-size: 13.5px;
  color: var(--cs-muted);
  max-width: 440px;
  margin: 0 auto 20px;
  line-height: 1.6;
}

.cs-proto-actions {
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 12px;
  flex-wrap: wrap;
}

.cs-proto-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 12px;
  color: var(--cs-pur-light);
  background: rgba(124, 58, 237, 0.08);
  border: 1px solid rgba(124, 58, 237, 0.2);
  padding: 6px 14px;
  border-radius: 100px;
  font-weight: 600;
}

/* Bottom Pagination */
.cs-bottom-nav {
  margin-top: 60px;
  padding-top: 30px;
  border-top: 1px solid var(--cs-card-bdr);
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 16px;
  flex-wrap: wrap;
}

.cs-nav-btn {
  display: inline-flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  font-size: 13.5px;
  font-weight: 600;
  color: var(--cs-heading);
  padding: 10px 20px;
  border-radius: 100px;
  background: var(--cs-card-bg);
  border: 1px solid var(--cs-card-bdr);
  transition: all 0.2s ease;
}

.cs-nav-btn:hover {
  border-color: var(--cs-pur);
  color: var(--cs-pur);
  transform: translateY(-1px);
}

/* Responsive Breakpoints */
@media (max-width: 640px) {
  .cs-container {
    padding: 30px 16px 60px;
  }
  .cs-overview-grid {
    grid-template-columns: repeat(2, 1fr);
  }
  .cs-decisions-grid {
    grid-template-columns: 1fr;
  }
  .cs-outcome-grid {
    grid-template-columns: 1fr;
    gap: 14px;
  }
  .cs-flow-wrap {
    flex-direction: column;
    align-items: stretch;
  }
  .cs-flow-step {
    justify-content: center;
  }
  .cs-flow-sep {
    align-self: center;
    transform: rotate(90deg);
  }
}