/* ============================================================
   GROWTHUP Design System — BLACK EDITORIAL v8
   BLACK × WHITE × LIGHT × SALT
   ============================================================ */

/* ─── CSS Custom Properties ─── */
:root {
  /* Color — PRIMARY BLACK SYSTEM */
  --color-bg:           #000000;   /* 주 배경 — 완전한 블랙 */
  --color-bg-2:         #0A0A0A;   /* 보조 배경 */
  --color-surface:      #111111;   /* 카드·서피스 */
  --color-surface-2:    #181818;   /* 인터랙티브 요소 */

  /* 하위 호환 — 기존 변수명 유지 */
  --color-brand:        #000000;
  --color-brand-mid:    #0A0A0A;
  --color-brand-soft:   #111111;

  /* Color — Text */
  --color-white:        #FFFFFF;
  --text-primary:       #FFFFFF;
  --text-secondary:     #A0A0A0;
  --text-muted:         #606060;
  --text-on-light:      #000000;

  /* Color — Border */
  --color-border:       #262626;
  --color-border-soft:  #1A1A1A;
  --border-thin:        1px solid #262626;
  --border-subtle:      1px solid #1A1A1A;

  /* Color — Brand Signature */
  --color-light:        #FFFFFF;   /* LIGHT 시그니처 — 별 */
  --color-salt:         #FFFFFF;   /* SALT 시그니처 — 점 */
  --color-accent:       #FFFFFF;   /* CTA — 화이트 */
  --color-accent-light: #A0A0A0;

  /* 기존 블루 계열 제거 (하위 호환 무색화) */
  --color-accent-glow:  rgba(255, 255, 255, 0.06);
  --color-accent-blue:  #FFFFFF;

  /* Color — Gray Scale */
  --color-gray-50:      #FAFAFA;
  --color-gray-100:     #F5F5F5;
  --color-gray-200:     #E5E5E5;
  --color-gray-300:     #D4D4D4;
  --color-gray-400:     #A3A3A3;
  --color-gray-500:     #737373;
  --color-gray-600:     #525252;
  --color-gray-700:     #404040;
  --color-gray-800:     #262626;
  --color-gray-900:     #171717;

  /* Color — Status */
  --color-success:      #22C55E;
  --color-warning:      #EAB308;
  --color-error:        #EF4444;

  /* Typography */
  --font-sans:   'Pretendard', 'Inter', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono:   'JetBrains Mono', 'Fira Code', 'Courier New', monospace;
  --font-editorial: 'Helvetica Neue', 'Arial', sans-serif;

  --text-xs:    0.6875rem;  /* 11px */
  --text-sm:    0.8125rem;  /* 13px */
  --text-base:  1rem;       /* 16px */
  --text-lg:    1.125rem;   /* 18px */
  --text-xl:    1.25rem;    /* 20px */
  --text-2xl:   1.5rem;     /* 24px */
  --text-3xl:   1.875rem;   /* 30px */
  --text-4xl:   2.25rem;    /* 36px */
  --text-5xl:   3rem;       /* 48px */
  --text-6xl:   3.75rem;    /* 60px */
  --text-7xl:   4.5rem;     /* 72px */
  --text-8xl:   6rem;       /* 96px */
  --text-9xl:   8rem;       /* 128px */

  --font-normal:    400;
  --font-medium:    500;
  --font-semibold:  600;
  --font-bold:      700;
  --font-extrabold: 800;
  --font-black:     900;

  --leading-none:    1;
  --leading-tight:   1.1;
  --leading-snug:    1.3;
  --leading-normal:  1.6;
  --leading-relaxed: 1.75;

  /* Tracking — Editorial */
  --tracking-tightest: -0.05em;
  --tracking-tight:    -0.03em;
  --tracking-normal:    0em;
  --tracking-wide:      0.06em;
  --tracking-wider:     0.12em;
  --tracking-widest:    0.2em;

  /* Spacing */
  --space-1:   0.25rem;
  --space-2:   0.5rem;
  --space-3:   0.75rem;
  --space-4:   1rem;
  --space-5:   1.25rem;
  --space-6:   1.5rem;
  --space-8:   2rem;
  --space-10:  2.5rem;
  --space-12:  3rem;
  --space-16:  4rem;
  --space-20:  5rem;
  --space-24:  6rem;
  --space-32:  8rem;
  --space-40:  10rem;
  --space-48:  12rem;

  /* Section Rhythm */
  --section-py:     8rem;
  --section-py-sm:  5rem;
  --section-py-xs:  3.5rem;

  /* Layout */
  --max-width:      1280px;
  --max-width-wide: 1440px;
  --max-width-text: 680px;
  --nav-height:     72px;
  --container-px:   2rem;

  /* Border Radius */
  --radius-sm:   2px;
  --radius-md:   4px;
  --radius-lg:   6px;
  --radius-xl:   8px;
  --radius-2xl:  12px;
  --radius-full: 9999px;

  /* Shadow */
  --shadow-sm:   0 1px 2px rgba(0, 0, 0, 0.8);
  --shadow-md:   0 4px 12px rgba(0, 0, 0, 0.9);
  --shadow-lg:   0 8px 24px rgba(0, 0, 0, 1);
  --shadow-xl:   0 16px 40px rgba(0, 0, 0, 1);
  --shadow-accent: 0 0 0 1px rgba(255, 255, 255, 0.15);

  /* Transitions */
  --transition-fast:   120ms ease;
  --transition-base:   240ms ease;
  --transition-slow:   400ms ease;
  --transition-spring: 350ms cubic-bezier(0.34, 1.56, 0.64, 1);

  /* Z-index */
  --z-below:    -1;
  --z-base:      0;
  --z-raised:   10;
  --z-dropdown: 100;
  --z-sticky:   200;
  --z-fixed:    300;
  --z-modal:    400;
  --z-toast:    500;
}

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

html {
  font-size: 16px;
  scroll-behavior: smooth;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: var(--font-sans);
  font-size: var(--text-base);
  font-weight: var(--font-normal);
  line-height: var(--leading-normal);
  color: var(--text-primary);
  background-color: var(--color-bg);
  overflow-x: hidden;
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

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

img, svg, video {
  display: block;
  max-width: 100%;
}

ul, ol { list-style: none; }

button {
  font-family: inherit;
  cursor: pointer;
  border: none;
  background: none;
}

input, textarea, select {
  font-family: inherit;
}

/* ─── Container ─── */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin-inline: auto;
  padding-inline: var(--container-px);
}

.container--wide {
  max-width: var(--max-width-wide);
}

/* ─── Section ─── */
.section {
  padding-block: var(--section-py);
}

.section--dark   { background-color: var(--color-bg); }
.section--mid    { background-color: var(--color-bg-2); }
.section--surface { background-color: var(--color-surface); }
.section--light  { background-color: var(--color-white); color: var(--text-on-light); }

/* ─── Typography — Editorial Display ─── */
.heading-display {
  font-size: clamp(var(--text-5xl), 7vw, var(--text-9xl));
  font-weight: var(--font-black);
  line-height: var(--leading-none);
  letter-spacing: var(--tracking-tightest);
}

.heading-xl {
  font-size: clamp(var(--text-4xl), 5vw, var(--text-7xl));
  font-weight: var(--font-black);
  line-height: var(--leading-tight);
  letter-spacing: var(--tracking-tight);
}

.heading-lg {
  font-size: clamp(var(--text-3xl), 3.5vw, var(--text-5xl));
  font-weight: var(--font-bold);
  line-height: var(--leading-snug);
  letter-spacing: -0.02em;
}

.heading-md {
  font-size: clamp(var(--text-2xl), 2.5vw, var(--text-4xl));
  font-weight: var(--font-bold);
  line-height: var(--leading-snug);
  letter-spacing: -0.015em;
}

.heading-sm {
  font-size: clamp(var(--text-xl), 2vw, var(--text-3xl));
  font-weight: var(--font-semibold);
  line-height: var(--leading-snug);
}

/* ─── Typography — Body ─── */
.body-lg  { font-size: var(--text-lg); line-height: var(--leading-relaxed); }
.body-md  { font-size: var(--text-base); line-height: var(--leading-normal); }
.body-sm  { font-size: var(--text-sm); line-height: var(--leading-normal); }
.body-xs  { font-size: var(--text-xs); line-height: var(--leading-normal); }

/* ─── Label / Tag — Editorial Style ─── */
.label {
  display: inline-flex;
  align-items: center;
  gap: var(--space-3);
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  letter-spacing: var(--tracking-widest);
  text-transform: uppercase;
  color: var(--text-muted);
}

/* 기존 ::before 라인 제거 (신규 스타일 적용) */
.label::before {
  content: none;
}

/* ─── Section Index Number ─── */
.section-index {
  font-size: var(--text-xs);
  font-weight: var(--font-normal);
  letter-spacing: var(--tracking-widest);
  color: var(--text-muted);
  text-transform: uppercase;
}

/* ─── Section Header ─── */
.section-header {
  margin-bottom: var(--space-16);
}

.section-header .label {
  margin-bottom: var(--space-6);
}

.section-header .heading-lg {
  margin-bottom: var(--space-6);
}

.section-header p {
  color: var(--text-secondary);
  font-size: var(--text-lg);
  max-width: var(--max-width-text);
  line-height: var(--leading-relaxed);
}

/* ─── Divider ─── */
.divider {
  width: 100%;
  height: 1px;
  background: var(--color-border);
  border: none;
}

/* ─── Buttons — Minimal Editorial ─── */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: var(--space-2);
  padding: var(--space-3) var(--space-6);
  font-size: var(--text-sm);
  font-weight: var(--font-semibold);
  letter-spacing: var(--tracking-wide);
  text-transform: uppercase;
  line-height: 1;
  border-radius: 0;
  transition: all var(--transition-base);
  white-space: nowrap;
  cursor: pointer;
  text-decoration: none;
}

/* Primary: 흰 배경 검정 글씨 */
.btn--primary {
  background: var(--color-white);
  color: var(--color-bg);
  border: 1px solid var(--color-white);
}

.btn--primary:hover {
  background: var(--color-gray-100);
  border-color: var(--color-gray-100);
}

/* Outline: 투명 배경 흰 테두리 */
.btn--outline {
  background: transparent;
  color: var(--text-primary);
  border: 1px solid var(--color-border);
}

.btn--outline:hover {
  border-color: rgba(255, 255, 255, 0.4);
  background: rgba(255, 255, 255, 0.04);
}

/* Ghost: 텍스트 + 화살표 */
.btn--ghost {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid transparent;
  padding-inline: 0;
  letter-spacing: var(--tracking-wide);
}

.btn--ghost:hover {
  color: var(--color-white);
}

.btn--sm {
  padding: var(--space-2) var(--space-4);
  font-size: var(--text-xs);
}

.btn--lg {
  padding: var(--space-4) var(--space-8);
  font-size: var(--text-sm);
}

.btn--icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 40px;
  height: 40px;
  padding: 0;
}

.btn--ghost .btn-arrow {
  display: inline-block;
  transition: transform var(--transition-base);
}

.btn--ghost:hover .btn-arrow {
  transform: translateX(4px);
}

/* ─── Card Base ─── */
.card {
  background: var(--color-surface);
  border: 1px solid var(--color-border);
  border-radius: 0;
  padding: var(--space-8);
  transition: border-color var(--transition-base);
}

.card:hover {
  border-color: rgba(255, 255, 255, 0.2);
}

/* ─── Badge / Chip ─── */
.badge {
  display: inline-flex;
  align-items: center;
  gap: var(--space-1);
  padding: var(--space-1) var(--space-3);
  font-size: var(--text-xs);
  font-weight: var(--font-medium);
  letter-spacing: var(--tracking-wider);
  text-transform: uppercase;
  border-radius: 0;
  background: transparent;
  color: var(--text-muted);
  border: 1px solid var(--color-border);
}

.badge--success {
  color: var(--color-success);
  border-color: rgba(34, 197, 94, 0.3);
  background: rgba(34, 197, 94, 0.05);
}

.badge--neutral {
  color: var(--text-muted);
  border-color: var(--color-border);
}

/* ─── Form Elements ─── */
.form-group {
  display: flex;
  flex-direction: column;
  gap: var(--space-2);
}

.form-label {
  font-size: var(--text-xs);
  font-weight: var(--font-semibold);
  letter-spacing: var(--tracking-wider);
  text-transform: uppercase;
  color: var(--text-muted);
}

.form-label .required {
  color: var(--color-error);
  margin-left: 2px;
}

.form-input,
.form-textarea,
.form-select {
  width: 100%;
  padding: var(--space-3) var(--space-4);
  font-size: var(--text-sm);
  font-family: var(--font-sans);
  color: var(--text-primary);
  background: transparent;
  border: none;
  border-bottom: 1px solid var(--color-border);
  border-radius: 0;
  transition: border-color var(--transition-fast);
  outline: none;
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--text-muted);
}

.form-input:focus,
.form-textarea:focus,
.form-select:focus {
  border-bottom-color: var(--color-white);
}

.form-textarea {
  resize: vertical;
  min-height: 120px;
}

.form-select {
  appearance: none;
  cursor: pointer;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='10' height='10' viewBox='0 0 10 10'%3E%3Cpath fill='%23606060' d='M5 7L1 3h8z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 0 center;
  padding-right: var(--space-8);
}

.form-select option {
  background: var(--color-surface);
}

/* ─── Grid Utilities ─── */
.grid-2 { display: grid; grid-template-columns: repeat(2, 1fr); gap: var(--space-6); }
.grid-3 { display: grid; grid-template-columns: repeat(3, 1fr); gap: var(--space-6); }
.grid-4 { display: grid; grid-template-columns: repeat(4, 1fr); gap: var(--space-6); }

/* ─── Flex Utilities ─── */
.flex         { display: flex; }
.flex-col     { flex-direction: column; }
.items-center { align-items: center; }
.items-start  { align-items: flex-start; }
.justify-between { justify-content: space-between; }
.justify-center  { justify-content: center; }
.gap-2  { gap: var(--space-2); }
.gap-4  { gap: var(--space-4); }
.gap-6  { gap: var(--space-6); }
.gap-8  { gap: var(--space-8); }

/* ─── Text Utilities ─── */
.text-center    { text-align: center; }
.text-accent    { color: var(--color-white); }
.text-muted     { color: var(--text-muted); }
.text-secondary { color: var(--text-secondary); }

/* ─── Visibility ─── */
.sr-only {
  position: absolute;
  width: 1px;
  height: 1px;
  padding: 0;
  margin: -1px;
  overflow: hidden;
  clip: rect(0, 0, 0, 0);
  white-space: nowrap;
  border: 0;
}

/* ─── GROWTHUP Star Signature (LIGHT) ─── */
/* 4포인트 스파클 — P 우상단 위치 형태 복원 */
.star-signature {
  display: inline-block;
  width: 1em;
  height: 1em;
  position: relative;
  flex-shrink: 0;
}

/* ─── Animation ─── */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(16px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInUp {
  from { opacity: 0; transform: translateY(32px); }
  to   { opacity: 1; transform: translateY(0); }
}

@keyframes fadeInLeft {
  from { opacity: 0; transform: translateX(-20px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes fadeInRight {
  from { opacity: 0; transform: translateX(20px); }
  to   { opacity: 1; transform: translateX(0); }
}

@keyframes scaleIn {
  from { opacity: 0; transform: scale(0.95); }
  to   { opacity: 1; transform: scale(1); }
}

/* Star twinkle — 아주 미세하게 */
@keyframes starTwinkle {
  0%, 100% { opacity: 1; transform: scale(1) rotate(0deg); }
  50%       { opacity: 0.7; transform: scale(0.92) rotate(15deg); }
}

.star-twinkle {
  animation: starTwinkle 4s ease-in-out infinite;
}

/* ─── Scroll Reveal ─── */
[data-reveal] {
  opacity: 0;
  transform: translateY(24px);
  transition: opacity 0.7s ease, transform 0.7s ease;
}

[data-reveal].revealed {
  opacity: 1;
  transform: translateY(0);
}

[data-reveal="left"] {
  transform: translateX(-24px);
}

[data-reveal="left"].revealed {
  transform: translateX(0);
}

[data-reveal="right"] {
  transform: translateX(24px);
}

[data-reveal="right"].revealed {
  transform: translateX(0);
}

[data-reveal="fade"] {
  transform: none;
}

[data-reveal="fade"].revealed {
  transform: none;
}

[data-reveal-delay="80"]  { transition-delay: 0.08s; }
[data-reveal-delay="100"] { transition-delay: 0.1s; }
[data-reveal-delay="160"] { transition-delay: 0.16s; }
[data-reveal-delay="180"] { transition-delay: 0.18s; }
[data-reveal-delay="200"] { transition-delay: 0.2s; }
[data-reveal-delay="220"] { transition-delay: 0.22s; }
[data-reveal-delay="280"] { transition-delay: 0.28s; }
[data-reveal-delay="300"] { transition-delay: 0.3s; }
[data-reveal-delay="360"] { transition-delay: 0.36s; }
[data-reveal-delay="400"] { transition-delay: 0.4s; }
[data-reveal-delay="500"] { transition-delay: 0.5s; }
[data-reveal-delay="600"] { transition-delay: 0.6s; }

/* ─── Responsive Breakpoints ─── */
@media (max-width: 1024px) {
  :root {
    --section-py: var(--section-py-sm);
    --container-px: 1.5rem;
  }
  .grid-4 { grid-template-columns: repeat(2, 1fr); }
  .grid-3 { grid-template-columns: repeat(2, 1fr); }
}

@media (max-width: 768px) {
  :root {
    --section-py: var(--section-py-xs);
    --container-px: 1.25rem;
    --nav-height: 60px;
  }
  .grid-4,
  .grid-3,
  .grid-2 { grid-template-columns: 1fr; }
}