/* ============================================
   BCCP Common Styles
   Version: 1.0.0
   ============================================ */

/* --- CSS Variables --- */
:root {
  --bg: #0a0a0a;
  --surface: #111;
  --border: #1a1a1a;
  --text: #e5e5e5;
  --muted: #666;
  --accent: #fff;
  
  /* Spacing */
  --header-padding: 1.5rem 3rem;
  --footer-padding: 1.5rem 3rem;
  --content-max-width: 640px;
  
  /* Typography */
  --font-main: 'Noto Sans JP', -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
  --font-mono: 'JetBrains Mono', 'SF Mono', Consolas, monospace;
  
  /* Transitions */
  --transition-fast: 0.2s ease;
  --transition-normal: 0.3s ease;
}

/* --- Reset --- */
* {
  margin: 0;
  padding: 0;
  box-sizing: border-box;
}

/* --- Base --- */
body {
  font-family: var(--font-main);
  background: var(--bg);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.8;
}

/* --- Header --- */
header {
  position: fixed;
  top: 0;
  width: 100%;
  padding: var(--header-padding);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-bottom: 1px solid var(--border);
  z-index: 100;
}

.logo {
  font-size: 0.875rem;
  font-weight: 600;
  letter-spacing: 0.2em;
  color: var(--accent);
  text-decoration: none;
  transition: opacity var(--transition-normal);
}

.logo:hover {
  opacity: 0.8;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 2rem;
}

/* --- Navigation --- */
nav {
  display: flex;
  gap: 2.5rem;
}

nav a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.8rem;
  letter-spacing: 0.05em;
  transition: color var(--transition-normal);
  position: relative;
}

nav a::after {
  content: '';
  position: absolute;
  bottom: -4px;
  left: 0;
  width: 0;
  height: 1px;
  background: var(--accent);
  transition: width var(--transition-normal);
}

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

nav a:hover::after,
nav a.active::after {
  width: 100%;
}

/* --- Language Selector --- */
.lang-selector {
  display: flex;
  gap: 0.5rem;
  border-left: 1px solid var(--border);
  padding-left: 2rem;
}

.lang-btn {
  background: none;
  border: 1px solid var(--border);
  color: var(--muted);
  padding: 0.25rem 0.5rem;
  font-size: 0.65rem;
  letter-spacing: 0.05em;
  cursor: pointer;
  transition: all var(--transition-normal);
}

.lang-btn:hover {
  border-color: var(--muted);
  color: var(--text);
}

.lang-btn.active {
  border-color: var(--accent);
  color: var(--accent);
}

/* --- Main Content --- */
main {
  min-height: 100vh;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  padding: 8rem 3rem;
}

.content {
  max-width: var(--content-max-width);
  width: 100%;
  animation: fadeIn 0.8s ease-out;
}

/* --- Page Title --- */
h1 {
  font-size: 1.5rem;
  font-weight: 300;
  letter-spacing: 0.1em;
  margin-bottom: 3rem;
  color: var(--accent);
}

/* --- Section Headings --- */
h2 {
  font-size: 0.8rem;
  font-weight: 600;
  letter-spacing: 0.1em;
  margin: 2.5rem 0 1rem;
  color: var(--text);
  position: relative;
  padding-left: 1rem;
}

h2::before {
  content: '';
  position: absolute;
  left: 0;
  top: 50%;
  transform: translateY(-50%);
  width: 3px;
  height: 100%;
  background: linear-gradient(to bottom, var(--muted), transparent);
}

h2:first-of-type {
  margin-top: 0;
}

/* --- Paragraphs --- */
p {
  font-size: 0.85rem;
  color: var(--muted);
  margin-bottom: 1rem;
  line-height: 2;
}

/* --- Footer --- */
footer {
  position: fixed;
  bottom: 0;
  width: 100%;
  padding: var(--footer-padding);
  display: flex;
  justify-content: space-between;
  align-items: center;
  background: rgba(10, 10, 10, 0.85);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border-top: 1px solid var(--border);
}

.copyright {
  font-size: 0.7rem;
  color: var(--muted);
  letter-spacing: 0.05em;
}

.footer-links {
  display: flex;
  gap: 2rem;
}

.footer-links a {
  color: var(--muted);
  text-decoration: none;
  font-size: 0.7rem;
  letter-spacing: 0.05em;
  transition: color var(--transition-normal);
}

.footer-links a:hover,
.footer-links a.active {
  color: var(--accent);
}

/* --- Forms --- */
input,
textarea {
  width: 100%;
  padding: 1rem;
  background: var(--surface);
  border: 1px solid var(--border);
  color: var(--text);
  font-family: inherit;
  font-size: 0.9rem;
  transition: border-color var(--transition-normal), box-shadow var(--transition-normal);
}

input:focus,
textarea:focus {
  outline: none;
  border-color: var(--muted);
  box-shadow: 0 0 0 1px rgba(102, 102, 102, 0.1);
}

input::placeholder,
textarea::placeholder {
  color: var(--muted);
  transition: opacity var(--transition-normal);
}

input:focus::placeholder,
textarea:focus::placeholder {
  opacity: 0.5;
}

textarea {
  min-height: 140px;
  resize: vertical;
}

/* --- Buttons --- */
button {
  padding: 1rem 2rem;
  background: transparent;
  border: 1px solid var(--border);
  color: var(--muted);
  font-size: 0.8rem;
  letter-spacing: 0.1em;
  cursor: pointer;
  transition: all var(--transition-normal);
}

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

button:active {
  transform: translateY(0);
}

/* --- Code --- */
code {
  font-family: var(--font-mono);
  font-size: 0.8rem;
  background: var(--surface);
  padding: 0.2rem 0.4rem;
  border: 1px solid var(--border);
}

pre {
  background: var(--surface);
  border: 1px solid var(--border);
  padding: 1.5rem;
  overflow-x: auto;
  margin: 1rem 0;
  font-size: 0.8rem;
  transition: border-color var(--transition-normal);
}

pre:hover {
  border-color: var(--muted);
}

pre code {
  background: none;
  border: none;
  padding: 0;
  font-family: var(--font-mono);
}

/* --- Animations --- */
@keyframes fadeIn {
  from {
    opacity: 0;
    transform: translateY(20px);
  }
  to {
    opacity: 1;
    transform: translateY(0);
  }
}

@keyframes pulse {
  0%, 100% { opacity: 0.5; }
  50% { opacity: 1; }
}

@keyframes shimmer {
  0%, 100% { background-position: 0% 50%; }
  50% { background-position: 100% 50%; }
}

/* --- Utilities --- */
.note {
  font-size: 0.8rem;
  color: var(--muted);
  font-style: italic;
}

/* --- Responsive --- */
@media (max-width: 768px) {
  :root {
    --header-padding: 1rem 1.5rem;
    --footer-padding: 1rem 1.5rem;
  }

  header {
    flex-wrap: wrap;
    gap: 1rem;
  }

  .header-right {
    width: 100%;
    justify-content: space-between;
  }

  .lang-selector {
    border-left: none;
    padding-left: 0;
  }

  nav {
    gap: 1.5rem;
  }

  main {
    padding: 6rem 1.5rem;
  }

  h1 {
    font-size: 1.25rem;
  }

  .footer-links {
    gap: 1rem;
  }
}