/* =============================================
   STUDIO SW — style.css
   Mobile-first responsive dark theme design system
   ============================================= */

/* -----------------------------------------------
   CSS Custom Properties (Design Tokens)
   ----------------------------------------------- */
:root {
  /* Colors */
  --color-bg-hero: #0a0f1e;
  --color-bg-dark: #0a0a0a;
  --color-bg-product: #0d0d0d;
  --color-bg-services: #111116;
  --color-bg-about: #0d0d0d;
  --color-bg-contact: #0a0a0a;
  --color-text-primary: #e0e0e0;
  --color-text-heading: #ffffff;
  --color-text-muted: #888888;
  --color-accent: #4a9eff;
  --color-border-subtle: rgba(255, 255, 255, 0.1);

  /* Spacing */
  --section-padding: 5rem 1.5rem;
  --section-padding-md: 6rem 2rem;
  --section-padding-lg: 7.5rem 2rem;
  --max-width: 1100px;
  --nav-height: 64px;

  /* Typography */
  --font-body: 'Pretendard', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-size-base: 1rem;
  --line-height-body: 1.7;
}

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

html {
  scroll-behavior: smooth;
}

body {
  font-family: var(--font-body);
  font-size: var(--font-size-base);
  line-height: var(--line-height-body);
  color: var(--color-text-primary);
  background: var(--color-bg-dark);
  -webkit-font-smoothing: antialiased;
  -moz-osx-font-smoothing: grayscale;
}

/* Fixed header offset for anchor scroll targets */
section[id] {
  scroll-margin-top: var(--nav-height);
}

/* -----------------------------------------------
   Layout Utilities
   ----------------------------------------------- */
.container {
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 1.5rem;
}

/* -----------------------------------------------
   Header & Navigation
   ----------------------------------------------- */
.site-header {
  position: fixed;
  top: 0;
  width: 100%;
  background: transparent;
  z-index: 1000;
  height: var(--nav-height);
  display: flex;
  align-items: center;
  padding: 0 1.5rem;
  transition: background 0.3s ease;
}

.site-header.scrolled {
  background: var(--color-bg-hero);
}

.header-inner {
  display: flex;
  justify-content: space-between;
  align-items: center;
  max-width: var(--max-width);
  margin: 0 auto;
  width: 100%;
}

.logo {
  color: var(--color-text-heading);
  font-weight: 700;
  font-size: 1.25rem;
  text-decoration: none;
  letter-spacing: 0.05em;
}

/* Desktop Nav — hidden on mobile */
.nav-desktop {
  display: none;
  align-items: center;
}

.nav-desktop a {
  color: var(--color-text-primary);
  text-decoration: none;
  margin-left: 2rem;
  font-size: 0.9rem;
  transition: color 0.2s;
}

.nav-desktop a:hover,
.nav-desktop a.active {
  color: var(--color-accent);
}

.nav-cta {
  background: var(--color-accent);
  color: #ffffff !important;
  padding: 0.5rem 1.25rem;
  border-radius: 6px;
  font-weight: 600;
  text-decoration: none;
  transition: filter 0.2s;
}

.nav-cta:hover {
  filter: brightness(1.1);
}

/* Hamburger button — shown on mobile */
.hamburger {
  display: flex;
  flex-direction: column;
  gap: 5px;
  background: none;
  border: none;
  cursor: pointer;
  padding: 0.5rem;
}

.hamburger span {
  display: block;
  width: 24px;
  height: 2px;
  background: var(--color-text-heading);
  transition: all 0.3s ease;
}

.hamburger.active span:nth-child(1) {
  transform: rotate(45deg) translateY(7px);
}

.hamburger.active span:nth-child(2) {
  opacity: 0;
}

.hamburger.active span:nth-child(3) {
  transform: rotate(-45deg) translateY(-7px);
}

/* Mobile Nav Overlay */
.nav-mobile {
  display: none;
  position: fixed;
  inset: 0;
  background: var(--color-bg-hero);
  z-index: 999;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 2rem;
}

.nav-mobile.active {
  display: flex;
}

.nav-mobile a {
  color: var(--color-text-heading);
  text-decoration: none;
  font-size: 1.5rem;
  font-weight: 500;
  transition: color 0.2s;
}

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

.nav-mobile .nav-cta {
  font-size: 1.25rem;
}

/* Prevent body scroll when mobile nav is open */
body.nav-open {
  overflow: hidden;
}

/* -----------------------------------------------
   Hero Section
   ----------------------------------------------- */
.hero {
  min-height: 100vh;
  background: linear-gradient(135deg, var(--color-bg-hero) 0%, var(--color-bg-dark) 100%);
  position: relative;
  overflow: hidden;
  display: flex;
  align-items: center;
  justify-content: center;
  text-align: center;
  padding: var(--section-padding);
}

/* Large circle accent — top right */
.hero::before {
  content: '';
  position: absolute;
  top: -150px;
  right: -150px;
  width: 500px;
  height: 500px;
  border-radius: 50%;
  border: 1px solid rgba(74, 158, 255, 0.15);
  pointer-events: none;
}

/* Bottom line accent */
.hero::after {
  content: '';
  position: absolute;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 2px;
  background: linear-gradient(90deg, transparent, var(--color-accent), transparent);
  opacity: 0.3;
}

.hero-content {
  position: relative;
  z-index: 1;
  max-width: 800px;
}

.hero h1 {
  color: var(--color-text-heading);
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 1.5rem;
  line-height: 1.4;
}

.hero-sub {
  color: var(--color-text-primary);
  font-size: 1rem;
  margin-bottom: 2rem;
  line-height: 1.8;
}

.btn-primary {
  display: inline-block;
  background: var(--color-accent);
  color: #ffffff;
  padding: 0.875rem 2rem;
  border-radius: 8px;
  font-weight: 600;
  text-decoration: none;
  font-size: 1rem;
  border: none;
  cursor: pointer;
  transition: filter 0.2s, transform 0.2s;
  font-family: var(--font-body);
}

.btn-primary:hover {
  filter: brightness(1.1);
  transform: translateY(-1px);
}

/* -----------------------------------------------
   Section Base
   ----------------------------------------------- */
.section {
  padding: var(--section-padding);
}

h2 {
  color: var(--color-text-heading);
  font-size: 1.75rem;
  font-weight: 700;
  margin-bottom: 0.75rem;
}

.section-subtitle {
  color: var(--color-text-muted);
  font-size: 1.05rem;
  margin-bottom: 2.5rem;
}

/* -----------------------------------------------
   Product Section
   ----------------------------------------------- */
.section-product {
  background: var(--color-bg-product);
}

.section-product p {
  margin-bottom: 2rem;
}

.features-list {
  list-style: none;
  padding: 0;
  margin-bottom: 3rem;
}

.features-list li {
  padding: 0.5rem 0;
  padding-left: 1.5rem;
  position: relative;
  color: var(--color-text-primary);
}

.features-list li::before {
  content: '—';
  position: absolute;
  left: 0;
  color: var(--color-accent);
}

/* Steps Grid */
.steps-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 2rem;
}

.step-card {
  padding: 1.5rem;
}

.step-number {
  font-size: 3rem;
  font-weight: 700;
  color: var(--color-accent);
  opacity: 0.8;
  line-height: 1;
  margin-bottom: 1rem;
}

.steps-grid h3 {
  color: var(--color-text-heading);
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.steps-grid p {
  margin-bottom: 0;
}

/* -----------------------------------------------
   Services Section
   ----------------------------------------------- */
.section-services {
  background: var(--color-bg-services);
}

.services-grid {
  display: grid;
  grid-template-columns: 1fr;
  gap: 1.25rem;
  justify-content: center;
}

.service-card {
  background: rgba(255, 255, 255, 0.03);
  border: 1px solid var(--color-border-subtle);
  border-radius: 8px;
  padding: 1.75rem;
  transition: border-color 0.25s ease, transform 0.25s ease;
}

.service-card:hover {
  border-color: var(--color-accent);
  transform: translateY(-2px);
}

.service-card h3 {
  color: var(--color-text-heading);
  font-size: 1.1rem;
  margin-bottom: 0.75rem;
  font-weight: 600;
}

.service-card p {
  color: var(--color-text-primary);
  font-size: 0.95rem;
  line-height: 1.7;
}

/* -----------------------------------------------
   About Section
   ----------------------------------------------- */
.section-about {
  background: var(--color-bg-about);
}

.section-about p {
  margin-bottom: 1.5rem;
}

.mission {
  color: var(--color-text-muted);
  font-style: italic;
  border-left: 3px solid var(--color-accent);
  padding-left: 1.25rem;
  margin: 2rem 0;
}

.founder {
  margin-top: 2.5rem;
}

.founder h3 {
  color: var(--color-text-heading);
  font-size: 1.25rem;
  margin-bottom: 0.75rem;
}

/* -----------------------------------------------
   Contact Section
   ----------------------------------------------- */
.section-contact {
  background: var(--color-bg-contact);
}

.contact-form-wrapper {
  max-width: 600px;
  margin: 0 auto;
}

.form-group {
  margin-bottom: 1.25rem;
}

.form-group label {
  display: block;
  color: var(--color-text-muted);
  font-size: 0.9rem;
  margin-bottom: 0.5rem;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.75rem 1rem;
  background: rgba(255, 255, 255, 0.05);
  border: 1px solid var(--color-border-subtle);
  border-radius: 6px;
  color: var(--color-text-primary);
  font-family: var(--font-body);
  font-size: 1rem;
  transition: border-color 0.2s;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--color-accent);
}

.form-group textarea {
  resize: vertical;
}

.form-result {
  margin-top: 1rem;
  font-size: 0.95rem;
  min-height: 1.5rem;
}

.form-result--success {
  color: #4ade80;
}

.form-result--error {
  color: #f87171;
}

.form-result--pending {
  color: var(--color-text-muted);
}

.contact-email {
  color: var(--color-text-muted);
  margin-top: 2rem;
  text-align: center;
  font-size: 0.95rem;
}

.contact-email a {
  color: var(--color-accent);
  text-decoration: none;
}

/* -----------------------------------------------
   Footer
   ----------------------------------------------- */
.site-footer {
  background: var(--color-bg-contact);
  padding: 2rem 1.5rem;
  text-align: center;
  border-top: 1px solid var(--color-border-subtle);
}

.site-footer p {
  color: var(--color-text-muted);
  font-size: 0.85rem;
}

/* -----------------------------------------------
   Responsive — Tablet (768px+)
   ----------------------------------------------- */
@media (min-width: 768px) {
  /* Show desktop nav, hide hamburger */
  .nav-desktop {
    display: flex;
    align-items: center;
  }

  .hamburger {
    display: none;
  }

  .nav-mobile {
    display: none !important;
  }

  /* Typography scale up */
  .hero h1 {
    font-size: 2.5rem;
  }

  h2 {
    font-size: 2rem;
  }

  /* Section padding increase */
  .section-product,
  .section-services,
  .section-about,
  .section-contact {
    padding: var(--section-padding-md);
  }

  /* Steps grid: 3 columns */
  .steps-grid {
    grid-template-columns: repeat(3, 1fr);
  }

  /* Services grid: 2 columns */
  .services-grid {
    grid-template-columns: repeat(2, 1fr);
  }
}

/* -----------------------------------------------
   Responsive — Desktop (1024px+)
   ----------------------------------------------- */
@media (min-width: 1024px) {
  .hero h1 {
    font-size: 3rem;
  }

  .section-product,
  .section-services,
  .section-about,
  .section-contact {
    padding: var(--section-padding-lg);
  }

  /* Services grid: 3 columns (5 cards, last 2 centered) */
  .services-grid {
    grid-template-columns: repeat(3, 1fr);
    justify-content: center;
  }
}