/* ==========================================================================
   2.5D Business Card Portfolio Design System
   Light Mode (Default) & Dark Mode Theme System
   ========================================================================== */

/* --------------------------------------------------------------------------
   Light Theme (Default)
   -------------------------------------------------------------------------- */
:root {
  --theme-name: "light";

  /* Canvas & Surfaces */
  --bg-base: #f8fafc;
  --bg-surface: #ffffff;
  --bg-surface-elevated: #ffffff;
  --bg-viewport-radial: radial-gradient(circle at 50% 45%, #ffffff 0%, #f1f5f9 60%, #e2e8f0 100%);
  --bg-body-radial: radial-gradient(circle at 50% 0%, #e2e8f0 0%, #f8fafc 55%);
  --bg-curtain: #f8fafc;

  /* Borders & Shadows */
  --border-subtle: rgba(15, 23, 42, 0.08);
  --border-hover: rgba(79, 70, 229, 0.35);
  --border-active: rgba(2, 132, 199, 0.5);
  --card-box-shadow: 0 10px 25px -5px rgba(15, 23, 42, 0.06), 0 8px 10px -6px rgba(15, 23, 42, 0.04);
  --card-hover-shadow: 0 20px 30px -10px rgba(15, 23, 42, 0.12);

  /* Typography */
  --text-primary: #0f172a;
  --text-secondary: #475569;
  --text-muted: #64748b;
  --text-accent: #0284c7;

  /* Accent Colors */
  --accent-cyan: #0284c7;
  --accent-indigo: #4f46e5;
  --accent-purple: #7c3aed;
  --accent-pill-bg: rgba(2, 132, 199, 0.08);
  --accent-pill-border: rgba(2, 132, 199, 0.25);

  /* 2.5D Business Card (Light Paper Stock) */
  --card-width: 480px;
  --card-height: 290px;
  --card-radius: 20px;
  --card-front-bg: linear-gradient(135deg, #ffffff 0%, #fbfcfe 50%, #f1f5f9 100%);
  --card-back-bg: linear-gradient(135deg, #ffffff 0%, #f8fafc 60%, #eef2f6 100%);
  --card-face-border: 1px solid rgba(15, 23, 42, 0.09);
  --card-face-shadow: 
    inset 0 0 0 1px rgba(255, 255, 255, 0.9),
    0 25px 45px -10px rgba(15, 23, 42, 0.16),
    0 10px 20px -5px rgba(15, 23, 42, 0.08);
  --card-floor-shadow: radial-gradient(ellipse at center, rgba(15, 23, 42, 0.28) 0%, rgba(15, 23, 42, 0) 70%);
  --card-glare-bg: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.8) 0%, rgba(255, 255, 255, 0) 65%);

  /* Header & Navigation */
  --header-bg: rgba(248, 250, 252, 0.85);
  --header-border: rgba(15, 23, 42, 0.08);

  /* UI Component Surfaces */
  --quote-box-bg: rgba(79, 70, 229, 0.06);
  --callout-bg: #f8fafc;
  --callout-border: rgba(15, 23, 42, 0.07);
  --tech-pill-bg: #f1f5f9;
  --tech-pill-color: #334155;
  --tech-pill-border: rgba(15, 23, 42, 0.08);
  --contact-card-bg: linear-gradient(135deg, #ffffff 0%, #f8fafc 100%);
  --contact-card-border: rgba(79, 70, 229, 0.25);
  --contact-method-bg: #f8fafc;
  --btn-copy-bg: #4f46e5;
  --btn-copy-hover: #4338ca;
  --btn-external-bg: #f1f5f9;
  --btn-external-color: #0f172a;
  --btn-external-border: rgba(15, 23, 42, 0.1);

  /* Toast & Utilities */
  --toast-bg: #0f172a;
  --toast-color: #f8fafc;
  --toast-border: #38bdf8;
  --toggle-bg: rgba(255, 255, 255, 0.9);
  --toggle-border: rgba(15, 23, 42, 0.15);
  --toggle-text: #0f172a;
  --toggle-shadow: 0 4px 14px rgba(15, 23, 42, 0.1);

  /* Fonts */
  --font-display: 'Outfit', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-body: 'Plus Jakarta Sans', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-mono: 'JetBrains Mono', monospace;

  --transition-fast: 0.2s cubic-bezier(0.16, 1, 0.3, 1);
  --transition-normal: 0.4s cubic-bezier(0.16, 1, 0.3, 1);
}

/* --------------------------------------------------------------------------
   Dark Theme Override ([data-theme="dark"])
   -------------------------------------------------------------------------- */
[data-theme="dark"] {
  --theme-name: "dark";

  /* Canvas & Surfaces */
  --bg-base: #080b11;
  --bg-surface: #0f1420;
  --bg-surface-elevated: #161e2e;
  --bg-viewport-radial: radial-gradient(circle at 50% 45%, #182238 0%, #080b11 70%);
  --bg-body-radial: radial-gradient(circle at 50% 0%, #151b2c 0%, #080b11 60%);
  --bg-curtain: #080b11;

  /* Borders & Shadows */
  --border-subtle: rgba(255, 255, 255, 0.08);
  --border-hover: rgba(99, 102, 241, 0.4);
  --border-active: rgba(56, 189, 248, 0.5);
  --card-box-shadow: 0 10px 25px -5px rgba(0, 0, 0, 0.5);
  --card-hover-shadow: 0 20px 30px -10px rgba(0, 0, 0, 0.7);

  /* Typography */
  --text-primary: #f8fafc;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --text-accent: #38bdf8;

  /* Accent Colors */
  --accent-cyan: #38bdf8;
  --accent-indigo: #6366f1;
  --accent-purple: #a855f7;
  --accent-pill-bg: rgba(56, 189, 248, 0.1);
  --accent-pill-border: rgba(56, 189, 248, 0.25);

  /* 2.5D Business Card (Dark Carbon/Obsidian) */
  --card-front-bg: linear-gradient(135deg, #1b2334 0%, #0d121c 100%);
  --card-back-bg: linear-gradient(135deg, #131929 0%, #0b0f19 100%);
  --card-face-border: 1px solid rgba(255, 255, 255, 0.1);
  --card-face-shadow: 
    inset 0 0 0 1px rgba(255, 255, 255, 0.15),
    0 25px 50px -12px rgba(0, 0, 0, 0.7);
  --card-floor-shadow: radial-gradient(ellipse at center, rgba(0, 0, 0, 0.75) 0%, rgba(0, 0, 0, 0) 70%);
  --card-glare-bg: radial-gradient(circle at 50% 50%, rgba(255, 255, 255, 0.18) 0%, rgba(255, 255, 255, 0) 60%);

  /* Header & Navigation */
  --header-bg: rgba(8, 11, 17, 0.85);
  --header-border: rgba(255, 255, 255, 0.08);

  /* UI Component Surfaces */
  --quote-box-bg: rgba(99, 102, 241, 0.08);
  --callout-bg: #141b2a;
  --callout-border: rgba(255, 255, 255, 0.06);
  --tech-pill-bg: #141c2c;
  --tech-pill-color: #cbd5e1;
  --tech-pill-border: rgba(255, 255, 255, 0.08);
  --contact-card-bg: linear-gradient(135deg, #131929 0%, #0d121c 100%);
  --contact-card-border: rgba(99, 102, 241, 0.3);
  --contact-method-bg: #161e30;
  --btn-copy-bg: #6366f1;
  --btn-copy-hover: #4f46e5;
  --btn-external-bg: rgba(255, 255, 255, 0.08);
  --btn-external-color: #ffffff;
  --btn-external-border: rgba(255, 255, 255, 0.1);

  /* Toast & Utilities */
  --toast-bg: #1e293b;
  --toast-color: #38bdf8;
  --toast-border: #38bdf8;
  --toggle-bg: rgba(20, 27, 43, 0.85);
  --toggle-border: rgba(255, 255, 255, 0.15);
  --toggle-text: #f8fafc;
  --toggle-shadow: 0 4px 14px rgba(0, 0, 0, 0.4);
}

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

html {
  scroll-behavior: smooth;
  background-color: var(--bg-base);
  color: var(--text-primary);
  font-family: var(--font-body);
  line-height: 1.6;
  text-rendering: optimizeLegibility;
  -webkit-font-smoothing: antialiased;
  transition: background-color 0.3s ease, color 0.3s ease;
}

body {
  overflow-x: hidden;
  background: var(--bg-body-radial);
  transition: background 0.3s ease;
}

/* Container */
.container {
  width: 100%;
  max-width: 1080px;
  margin: 0 auto;
  padding: 0 24px;
}

/* Scroll Progress Bar */
#scroll-progress-container {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 3px;
  z-index: 1000;
  background: transparent;
}

#scroll-progress-bar {
  width: 0%;
  height: 100%;
  background: linear-gradient(90deg, var(--accent-indigo), var(--accent-cyan));
  transition: width 0.05s linear;
  box-shadow: 0 0 10px rgba(2, 132, 199, 0.4);
}

/* ==========================================================================
   Floating Theme Toggle Button (항상 접근 가능)
   ========================================================================== */
.floating-theme-toggle {
  position: fixed;
  top: 18px;
  right: 24px;
  z-index: 600;
  display: flex;
  align-items: center;
  gap: 8px;
  padding: 8px 16px;
  background: var(--toggle-bg);
  border: 1px solid var(--toggle-border);
  color: var(--toggle-text);
  border-radius: 30px;
  cursor: pointer;
  box-shadow: var(--toggle-shadow);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  font-family: var(--font-display);
  font-size: 0.85rem;
  font-weight: 600;
  transition: all var(--transition-fast);
}

.floating-theme-toggle:hover {
  transform: translateY(-2px);
  border-color: var(--accent-indigo);
  box-shadow: 0 6px 18px rgba(79, 70, 229, 0.2);
}

.theme-icon {
  font-size: 1rem;
  line-height: 1;
}

/* Header & Navigation */
.site-header {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 70px;
  z-index: 500;
  background: var(--header-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border-bottom: 1px solid var(--header-border);
  transform: translateY(-100%);
  opacity: 0;
  transition: transform 0.4s ease, opacity 0.4s ease, background 0.3s ease;
}

.site-header.visible {
  transform: translateY(0);
  opacity: 1;
}

.header-container {
  max-width: 1140px;
  height: 100%;
  margin: 0 auto;
  padding: 0 24px;
  padding-right: 120px; /* 토글 버튼 공간 확보 */
  display: flex;
  align-items: center;
  justify-content: space-between;
}

.brand-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  text-decoration: none;
  font-family: var(--font-display);
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.logo-badge {
  background: linear-gradient(135deg, var(--accent-indigo), var(--accent-cyan));
  padding: 3px 7px;
  border-radius: 6px;
  font-size: 0.75rem;
  font-family: var(--font-mono);
  color: #fff;
  font-weight: 700;
}

.nav-links {
  display: flex;
  align-items: center;
  gap: 24px;
}

.nav-links a {
  color: var(--text-secondary);
  text-decoration: none;
  font-size: 0.92rem;
  font-weight: 500;
  transition: color var(--transition-fast);
}

.nav-links a:hover {
  color: var(--accent-cyan);
}

.nav-btn-contact {
  background: var(--accent-pill-bg);
  border: 1px solid var(--accent-pill-border);
  color: var(--accent-cyan) !important;
  padding: 7px 16px;
  border-radius: 20px;
  transition: all var(--transition-fast) !important;
}

.nav-btn-contact:hover {
  background: var(--accent-indigo);
  color: #fff !important;
  box-shadow: 0 0 16px rgba(79, 70, 229, 0.3);
}

/* ==========================================================================
   Hero Track & 2.5D Card 3D Stage
   ========================================================================== */
.hero-track {
  position: relative;
  width: 100%;
  height: 380vh;
}

.sticky-viewport {
  position: sticky;
  top: 0;
  width: 100vw;
  height: 100vh;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  background: var(--bg-viewport-radial);
  transition: background 0.3s ease;
}

.scene-3d {
  width: 100%;
  height: 100%;
  display: flex;
  align-items: center;
  justify-content: center;
  perspective: 1200px;
  perspective-origin: 50% 50%;
  pointer-events: none;
}

/* The 3D Business Card */
.card-3d {
  position: relative;
  width: var(--card-width);
  height: var(--card-height);
  border-radius: var(--card-radius);
  transform-style: preserve-3d;
  will-change: transform, width, height, border-radius;
  pointer-events: auto;
  cursor: grab;
  /* 기본 초기 위치: 2.5D 아이소메트릭 기울기 */
  transform: rotateX(48deg) rotateY(-14deg) rotateZ(20deg) translateZ(0);
  transition: box-shadow 0.3s ease;
}

.card-3d:active {
  cursor: grabbing;
}

/* Floor Shadow */
.card-shadow {
  position: absolute;
  top: 15%;
  left: 5%;
  width: 90%;
  height: 80%;
  background: var(--card-floor-shadow);
  filter: blur(28px);
  transform: translateZ(-90px) rotateX(15deg);
  opacity: 0.85;
  pointer-events: none;
  transition: opacity 0.3s ease, transform 0.3s ease, background 0.3s ease;
}

/* Card Faces */
.card-face {
  position: absolute;
  inset: 0;
  width: 100%;
  height: 100%;
  border-radius: inherit;
  backface-visibility: hidden;
  -webkit-backface-visibility: hidden;
  overflow: hidden;
  box-shadow: var(--card-face-shadow);
  display: flex;
  flex-direction: column;
  transition: background 0.3s ease, box-shadow 0.3s ease, border-color 0.3s ease;
}

/* Front Face */
.card-front {
  background: var(--card-front-bg);
  border: var(--card-face-border);
  transform: rotateY(0deg);
}

/* Back Face */
.card-back {
  background: var(--card-back-bg);
  border: var(--card-face-border);
  transform: rotateY(180deg);
}

/* Specular Glare Effect */
.card-glare {
  position: absolute;
  inset: -50%;
  width: 200%;
  height: 200%;
  background: var(--card-glare-bg);
  pointer-events: none;
  opacity: 0.5;
  transform: translate(-30%, -30%);
  mix-blend-mode: overlay;
  transition: transform 0.1s linear, opacity 0.3s ease;
}

/* Card Inner Layouts */
.card-inner-content {
  position: relative;
  z-index: 2;
  height: 100%;
  padding: 30px 34px;
  display: flex;
  flex-direction: column;
  justify-content: space-between;
}

.card-top-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

/* Golden Microchip Element */
.card-chip {
  width: 44px;
  height: 32px;
  border-radius: 6px;
  background: linear-gradient(135deg, #d4af37 0%, #aa8222 100%);
  position: relative;
  box-shadow: inset 0 0 4px rgba(0, 0, 0, 0.25), 0 2px 6px rgba(0, 0, 0, 0.15);
  border: 1px solid rgba(255, 255, 255, 0.4);
}

.chip-lines {
  position: absolute;
  inset: 4px;
  border: 1px solid rgba(0, 0, 0, 0.25);
  border-radius: 3px;
}

.card-tag {
  font-family: var(--font-mono);
  font-size: 0.72rem;
  letter-spacing: 1.5px;
  color: var(--accent-cyan);
  background: var(--accent-pill-bg);
  border: 1px solid var(--accent-pill-border);
  padding: 4px 10px;
  border-radius: 12px;
  font-weight: 600;
}

.card-profile-intro {
  display: flex;
  align-items: center;
  gap: 16px;
  margin: 10px 0;
}

.card-avatar-monogram {
  width: 48px;
  height: 48px;
  border-radius: 12px;
  background: linear-gradient(135deg, var(--accent-indigo), var(--accent-cyan));
  display: flex;
  align-items: center;
  justify-content: center;
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 800;
  color: #fff;
  box-shadow: 0 4px 14px rgba(79, 70, 229, 0.3);
}

.card-name {
  font-family: var(--font-display);
  font-size: 1.45rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.5px;
}

.card-subtitle {
  font-size: 0.85rem;
  color: var(--text-secondary);
  margin-top: 2px;
}

.card-divider {
  width: 100%;
  height: 1px;
  background: linear-gradient(90deg, transparent, var(--border-subtle), transparent);
}

.card-bottom-row {
  display: flex;
  justify-content: space-between;
  align-items: flex-end;
}

.card-contact-meta {
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.meta-item {
  font-size: 0.78rem;
  color: var(--text-secondary);
  font-family: var(--font-mono);
}

.card-emblem {
  font-size: 1.3rem;
  color: var(--accent-cyan);
  opacity: 0.9;
}

/* Card Back Side Specific */
.back-layout {
  text-align: center;
  align-items: center;
  padding: 32px 36px;
}

.back-brand {
  display: flex;
  align-items: center;
  gap: 8px;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 2px;
  color: var(--accent-indigo);
  font-weight: 600;
}

.back-logo-mark {
  font-size: 1rem;
  color: var(--accent-cyan);
}

.back-quote {
  font-family: var(--font-display);
  font-size: 1.05rem;
  line-height: 1.55;
  color: var(--text-primary);
  font-weight: 600;
  margin: 10px 0;
  position: relative;
}

.back-footer-tags {
  display: flex;
  flex-wrap: wrap;
  justify-content: center;
  gap: 8px;
  margin-bottom: 6px;
}

.pill-tag {
  font-size: 0.72rem;
  font-family: var(--font-mono);
  color: var(--text-secondary);
  background: var(--accent-pill-bg);
  border: 1px solid var(--border-subtle);
  padding: 3px 8px;
  border-radius: 6px;
}

.back-expand-hint {
  display: flex;
  align-items: center;
  gap: 6px;
  font-size: 0.78rem;
  color: var(--accent-cyan);
  font-weight: 600;
}

.pulse-icon {
  animation: bounceDown 1.5s infinite;
}

@keyframes bounceDown {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(4px); }
}

/* Scroll Cue (Initial) */
.scroll-cue {
  position: absolute;
  bottom: 40px;
  left: 50%;
  transform: translateX(-50%);
  display: flex;
  flex-direction: column;
  align-items: center;
  gap: 12px;
  color: var(--text-secondary);
  font-size: 0.85rem;
  letter-spacing: -0.2px;
  pointer-events: none;
  transition: opacity 0.3s ease;
  z-index: 10;
}

.mouse-icon {
  width: 24px;
  height: 38px;
  border: 2px solid var(--text-muted);
  border-radius: 14px;
  position: relative;
}

.wheel {
  width: 4px;
  height: 8px;
  background: var(--accent-cyan);
  border-radius: 2px;
  position: absolute;
  top: 6px;
  left: 50%;
  transform: translateX(-50%);
  animation: scrollWheel 1.8s infinite;
}

@keyframes scrollWheel {
  0% { transform: translate(-50%, 0); opacity: 1; }
  80% { transform: translate(-50%, 12px); opacity: 0; }
  100% { transform: translate(-50%, 0); opacity: 0; }
}

/* Curtain for smooth zoom reveal */
.transition-curtain {
  position: absolute;
  inset: 0;
  background: var(--bg-curtain);
  opacity: 0;
  pointer-events: none;
  z-index: 50;
  transition: opacity 0.1s linear, background 0.3s ease;
}

/* ==========================================================================
   Full Expanded Website Styling
   ========================================================================== */
.main-website {
  position: relative;
  z-index: 100;
  background-color: var(--bg-base);
  min-height: 100vh;
  padding-bottom: 60px;
  transition: background-color 0.3s ease;
}

/* Hero Section */
.intro-hero {
  padding: 100px 0 80px 0;
  text-align: center;
}

.badge-hero {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  font-size: 0.82rem;
  font-weight: 600;
  font-family: var(--font-mono);
  color: var(--accent-cyan);
  background: var(--accent-pill-bg);
  border: 1px solid var(--accent-pill-border);
  padding: 6px 16px;
  border-radius: 30px;
  margin-bottom: 24px;
}

.main-headline {
  font-family: var(--font-display);
  font-size: 3.2rem;
  font-weight: 800;
  line-height: 1.25;
  letter-spacing: -1.5px;
  margin-bottom: 24px;
  color: var(--text-primary);
}

.gradient-text {
  background: linear-gradient(135deg, var(--accent-cyan) 0%, var(--accent-indigo) 50%, var(--accent-purple) 100%);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
}

.main-subheadline {
  font-size: 1.15rem;
  color: var(--text-secondary);
  max-width: 720px;
  margin: 0 auto 50px auto;
  line-height: 1.7;
}

/* Quick Overview Grid */
.quick-overview-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(230px, 1fr));
  gap: 20px;
  text-align: left;
}

.quick-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 16px;
  padding: 24px;
  box-shadow: var(--card-box-shadow);
  transition: transform var(--transition-normal), border-color var(--transition-normal), box-shadow var(--transition-normal);
}

.quick-card:hover {
  transform: translateY(-4px);
  border-color: var(--border-hover);
  box-shadow: var(--card-hover-shadow);
}

.card-icon {
  font-size: 1.6rem;
  margin-bottom: 12px;
}

.quick-card-title {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  letter-spacing: 1px;
  color: var(--accent-indigo);
  text-transform: uppercase;
  font-weight: 600;
  margin-bottom: 6px;
}

.quick-card-desc {
  font-size: 0.95rem;
  color: var(--text-primary);
  line-height: 1.5;
}

.link-items a {
  color: var(--accent-cyan);
  text-decoration: none;
  font-weight: 600;
}

.link-items a:hover {
  text-decoration: underline;
}

.highlight-text {
  color: var(--text-secondary);
}

/* Section Common */
.section-badge {
  display: inline-block;
  font-family: var(--font-mono);
  font-size: 0.75rem;
  letter-spacing: 2px;
  color: var(--accent-cyan);
  margin-bottom: 8px;
  font-weight: 600;
}

.section-heading {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  letter-spacing: -0.8px;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.section-subheading {
  font-size: 1.05rem;
  color: var(--text-secondary);
  margin-bottom: 40px;
}

/* Philosophy Strip */
.philosophy-strip-section {
  padding: 80px 0;
  border-top: 1px solid var(--border-subtle);
}

.philosophy-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(180px, 1fr));
  gap: 16px;
  margin-top: 30px;
}

.phil-item {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 14px;
  padding: 24px 20px;
  position: relative;
  box-shadow: var(--card-box-shadow);
  transition: all var(--transition-normal);
}

.phil-item:hover {
  border-color: var(--border-active);
  transform: translateY(-4px);
  box-shadow: var(--card-hover-shadow);
}

.phil-num {
  font-family: var(--font-mono);
  font-size: 1.1rem;
  font-weight: 800;
  color: var(--accent-cyan);
  opacity: 0.85;
  margin-bottom: 8px;
}

.phil-item h3 {
  font-family: var(--font-display);
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 10px;
  color: var(--text-primary);
}

.phil-item p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.55;
}

/* Interview Q&A Section */
.interview-section {
  padding: 80px 0;
  border-top: 1px solid var(--border-subtle);
}

.interview-list {
  display: flex;
  flex-direction: column;
  gap: 28px;
}

.interview-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 18px;
  padding: 34px 38px;
  box-shadow: var(--card-box-shadow);
  transition: border-color var(--transition-normal), transform var(--transition-normal), box-shadow var(--transition-normal);
}

.interview-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-2px);
  box-shadow: var(--card-hover-shadow);
}

.q-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 18px;
}

.q-badge {
  background: linear-gradient(135deg, var(--accent-indigo), var(--accent-purple));
  color: #fff;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  font-weight: 700;
  padding: 4px 10px;
  border-radius: 8px;
}

.q-header h3 {
  font-family: var(--font-display);
  font-size: 1.35rem;
  font-weight: 700;
  color: var(--text-primary);
  letter-spacing: -0.4px;
}

.quote-box {
  background: var(--quote-box-bg);
  border-left: 4px solid var(--accent-cyan);
  padding: 14px 20px;
  border-radius: 0 10px 10px 0;
  font-size: 1.02rem;
  font-weight: 600;
  color: var(--accent-cyan);
  margin-bottom: 20px;
}

.a-body {
  font-size: 0.98rem;
  color: var(--text-secondary);
  line-height: 1.75;
}

.a-body p {
  margin-bottom: 12px;
}

.detail-callouts {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(280px, 1fr));
  gap: 16px;
  margin-top: 20px;
}

.callout-box {
  background: var(--callout-bg);
  border: 1px solid var(--callout-border);
  border-radius: 12px;
  padding: 18px 20px;
}

.callout-box h4 {
  font-size: 0.95rem;
  color: var(--text-primary);
  margin-bottom: 8px;
}

.callout-box p {
  font-size: 0.88rem;
  color: var(--text-secondary);
  line-height: 1.6;
  margin: 0;
}

.styled-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 10px;
}

.styled-list li {
  position: relative;
  padding-left: 20px;
}

.styled-list li::before {
  content: "▹";
  position: absolute;
  left: 0;
  color: var(--accent-cyan);
  font-weight: bold;
}

.user-focus-bullets {
  display: flex;
  flex-direction: column;
  gap: 10px;
  margin-top: 14px;
}

.uf-item {
  background: var(--callout-bg);
  border-radius: 8px;
  padding: 12px 18px;
  font-size: 0.92rem;
  color: var(--text-primary);
  border-left: 3px solid var(--accent-indigo);
  border: 1px solid var(--border-subtle);
  border-left-width: 3px;
  border-left-color: var(--accent-indigo);
}

/* Tech Stack Section */
.tech-stack-section {
  padding: 80px 0;
  border-top: 1px solid var(--border-subtle);
}

.tech-grid {
  display: grid;
  grid-template-columns: repeat(auto-fit, minmax(300px, 1fr));
  gap: 24px;
}

.tech-category-card {
  background: var(--bg-surface);
  border: 1px solid var(--border-subtle);
  border-radius: 18px;
  padding: 28px;
  box-shadow: var(--card-box-shadow);
  transition: all var(--transition-normal);
}

.tech-category-card:hover {
  border-color: var(--border-hover);
  transform: translateY(-4px);
  box-shadow: var(--card-hover-shadow);
}

.tech-cat-header {
  display: flex;
  align-items: center;
  gap: 14px;
  margin-bottom: 22px;
}

.cat-icon {
  font-size: 2rem;
}

.tech-cat-header h3 {
  font-family: var(--font-display);
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--text-primary);
}

.tech-cat-header p {
  font-size: 0.82rem;
  color: var(--text-secondary);
}

.tag-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
}

.tech-pill {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background: var(--tech-pill-bg);
  color: var(--tech-pill-color);
  border: 1px solid var(--tech-pill-border);
  padding: 6px 12px;
  border-radius: 8px;
  transition: all var(--transition-fast);
}

.tech-pill:hover {
  background: rgba(79, 70, 229, 0.15);
  color: var(--accent-indigo);
  border-color: var(--accent-indigo);
}

.tech-pill.accent {
  background: var(--accent-pill-bg);
  color: var(--accent-cyan);
  border-color: var(--accent-pill-border);
  font-weight: 600;
}

/* Coffee Chat Section */
.contact-section {
  padding: 80px 0;
  border-top: 1px solid var(--border-subtle);
}

.contact-card-wrapper {
  background: var(--contact-card-bg);
  border: 1px solid var(--contact-card-border);
  border-radius: 24px;
  padding: 50px 40px;
  text-align: center;
  box-shadow: var(--card-hover-shadow);
}

.coffee-icon {
  font-size: 2.8rem;
  display: inline-block;
  margin-bottom: 12px;
}

.contact-header h2 {
  font-family: var(--font-display);
  font-size: 2.2rem;
  font-weight: 700;
  color: var(--text-primary);
  margin-bottom: 12px;
}

.contact-header p {
  color: var(--text-secondary);
  font-size: 1.05rem;
  line-height: 1.6;
  max-width: 600px;
  margin: 0 auto 36px auto;
}

.contact-methods {
  display: flex;
  justify-content: center;
  gap: 20px;
  flex-wrap: wrap;
  margin-bottom: 36px;
}

.contact-method-card {
  background: var(--contact-method-bg);
  border: 1px solid var(--border-subtle);
  border-radius: 16px;
  padding: 20px 28px;
  min-width: 260px;
  text-align: center;
}

.method-label {
  font-family: var(--font-mono);
  font-size: 0.75rem;
  color: var(--text-muted);
  text-transform: uppercase;
  letter-spacing: 1px;
  margin-bottom: 4px;
}

.method-value {
  font-family: var(--font-mono);
  font-size: 1rem;
  font-weight: 600;
  color: var(--text-primary);
  margin-bottom: 14px;
}

.btn-copy, .btn-external {
  display: inline-block;
  width: 100%;
  padding: 10px 16px;
  font-size: 0.88rem;
  font-weight: 600;
  border-radius: 10px;
  cursor: pointer;
  text-decoration: none;
  transition: all var(--transition-fast);
}

.btn-copy {
  background: var(--btn-copy-bg);
  color: #fff;
  border: none;
}

.btn-copy:hover {
  background: var(--btn-copy-hover);
  box-shadow: 0 0 16px rgba(79, 70, 229, 0.4);
}

.btn-external {
  background: var(--btn-external-bg);
  color: var(--btn-external-color);
  border: 1px solid var(--btn-external-border);
}

.btn-external:hover {
  background: rgba(79, 70, 229, 0.1);
  color: var(--accent-indigo);
  border-color: var(--accent-indigo);
}

.closing-quote {
  font-size: 1rem;
  color: var(--accent-cyan);
  opacity: 0.95;
  font-weight: 500;
}

/* Footer */
.site-footer {
  border-top: 1px solid var(--border-subtle);
  padding: 30px 0;
  font-size: 0.88rem;
  color: var(--text-muted);
}

.footer-content {
  display: flex;
  justify-content: space-between;
  align-items: center;
  flex-wrap: wrap;
  gap: 16px;
}

.btn-back-to-top {
  background: transparent;
  border: 1px solid var(--border-subtle);
  color: var(--text-secondary);
  padding: 8px 16px;
  border-radius: 8px;
  cursor: pointer;
  font-size: 0.82rem;
  transition: all var(--transition-fast);
}

.btn-back-to-top:hover {
  color: var(--text-primary);
  border-color: var(--accent-cyan);
}

/* Toast Notification */
.toast {
  position: fixed;
  bottom: 30px;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--toast-bg);
  color: var(--toast-color);
  border: 1px solid var(--toast-border);
  padding: 12px 24px;
  border-radius: 30px;
  font-size: 0.9rem;
  font-weight: 600;
  box-shadow: 0 10px 30px rgba(0, 0, 0, 0.2);
  z-index: 10000;
  opacity: 0;
  transition: transform 0.3s cubic-bezier(0.16, 1, 0.3, 1), opacity 0.3s ease;
  pointer-events: none;
}

.toast.show {
  transform: translateX(-50%) translateY(0);
  opacity: 1;
}

/* ==========================================================================
   Responsive Breakpoints
   ========================================================================== */
@media (max-width: 768px) {
  :root {
    --card-width: 90vw;
    --card-height: 240px;
  }

  .floating-theme-toggle {
    top: 12px;
    right: 16px;
    padding: 6px 12px;
    font-size: 0.78rem;
  }

  .header-container {
    padding-right: 16px;
  }

  .main-headline {
    font-size: 2.2rem;
  }

  .nav-links {
    display: none;
  }

  .interview-card {
    padding: 24px 20px;
  }

  .contact-card-wrapper {
    padding: 36px 20px;
  }

  .card-inner-content {
    padding: 20px 22px;
  }

  .card-name {
    font-size: 1.2rem;
  }

  .back-quote {
    font-size: 0.92rem;
  }
}