/* style.css - Boundary X: Bluetooth Keypad Edition (Mobile Responsive Fixed) */

:root {
  --primary: #000000;
  --primary-hover: #333333;
  --accent-grey: #F8F9FA;
  --border-color: #D1D5DB;
  --bg-color: #FFFFFF;
  --text-main: #111111;
  --text-sub: #666666;
  --danger: #EA4335;
  --success: #137333;
  
  --radius-pill: 50px;
  --radius-card: 16px;
  --font-family: 'Pretendard', -apple-system, sans-serif;
}

* { margin: 0; padding: 0; box-sizing: border-box; font-family: var(--font-family); }

body {
  background-color: var(--bg-color);
  color: var(--text-main);
  line-height: 1.6;
  min-height: 100vh;
  display: flex;
  flex-direction: column;
}

/* Header */
header {
  background: #000000;
  border-bottom: 1px solid #333;
  padding: 1rem 5vw;
  display: flex;
  justify-content: space-between;
  align-items: center;
  position: sticky;
  top: 0;
  z-index: 100;
  transition: padding 0.3s ease; /* 부드러운 전환 효과 추가 */
}
.title { font-size: 1.25rem; font-weight: 700; color: #FFFFFF; display: flex; align-items: center; gap: 12px; transition: font-size 0.3s ease; }
.title img { height: 28px; width: auto; transition: height 0.3s ease; } /* 이미지 크기 전환 효과 */

.back-button {
  text-decoration: none; color: #FFFFFF; border: 1px solid #FFFFFF;
  font-size: 0.9rem; font-weight: 500; padding: 0.5rem 1.2rem;
  border-radius: var(--radius-pill); transition: all 0.2s;
}
.back-button:hover { background: #FFFFFF; color: #000000; }

/* Main Layout */
main { width: 100%; max-width: 600px; margin: 0 auto; padding: 3rem 1.5rem; flex: 1; transition: padding 0.3s ease; }
.canvas-container, canvas { display: none; }
.controls { display: flex; flex-direction: column; gap: 32px; }
.control-group {
  background: var(--accent-grey); padding: 2rem;
  border-radius: var(--radius-card); border: 1px solid var(--border-color);
  transition: padding 0.3s ease;
}
.control-group h3 {
  border-left: 6px solid #000000; padding-left: 1rem;
  font-size: 1.3rem; font-weight: 800; margin-bottom: 1rem; line-height: 1.1;
}
.control-group p { color: var(--text-sub); font-size: 0.95rem; margin-bottom: 1.5rem; }

/* Buttons & Inputs */
.button-group { display: flex; gap: 12px; flex-wrap: wrap; }
button {
  cursor: pointer; border: none; font-size: 1rem; font-weight: 600;
  padding: 0.9rem 1.5rem; border-radius: var(--radius-pill); transition: all 0.2s;
}
.start-button { background-color: var(--primary); color: white; }
.start-button:hover { background-color: var(--primary-hover); transform: translateY(-2px); }
.stop-button { background-color: white; color: var(--danger); border: 1px solid var(--border-color); }
.stop-button:hover { background-color: #FFF5F5; border-color: var(--danger); }
#bluetooth-control-buttons button { flex: 1; }

/* Status Box */
#bluetoothStatus {
  padding: 1rem; border-radius: var(--radius-card); text-align: center; font-weight: 700;
  background-color: #F1F3F4; border: 1px solid var(--border-color); margin-bottom: 1rem;
}
.status-connected { background-color: #E6F4EA !important; color: var(--success) !important; border-color: var(--success) !important; }
.status-error { background-color: #FCE8E6 !important; color: var(--danger) !important; border-color: var(--danger) !important; }

/* --- Keypad UI --- */
.display-screen {
    background: #222;
    color: #0f0;
    padding: 1.5rem;
    border-radius: 12px;
    margin-bottom: 1.5rem;
    display: flex;
    justify-content: space-between;
    align-items: center;
    font-family: monospace;
    font-size: 1.2rem;
    box-shadow: inset 0 2px 5px rgba(0,0,0,0.5);
}
.display-screen .label { color: #888; font-size: 0.9rem; }
.display-screen .value { font-weight: bold; font-size: 1.5rem; }

.keypad-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr); /* 3열로 균등 분할 (반응형의 핵심) */
    gap: 12px;
}

.key-button {
    background: white;
    border: 1px solid var(--border-color);
    color: var(--text-main);
    font-size: 1.5rem !important;
    font-weight: 700;
    aspect-ratio: 1.4 / 1;
    border-radius: 12px !important;
    display: flex;
    align-items: center;
    justify-content: center;
    box-shadow: 0 4px 0px rgba(0,0,0,0.1);
    width: 100%; /* 부모 그리드 셀에 가득 차게 설정 */
}

.key-button:active {
    transform: translateY(4px);
    box-shadow: none;
    background: #eee;
}

/* Detailed Footer (Restored) */
footer {
  background-color: #000000;
  color: #FFFFFF;
  padding: 4rem 5vw 4rem;
  border-top: 1px solid #222;
  margin-top: auto;
  font-size: 0.9rem;
}

.footer-container {
  max-width: 1000px;
  margin: 0 auto;
  display: flex;
  flex-direction: column;
}

.footer-top {
  display: flex;
  justify-content: space-between;
  flex-wrap: wrap;
  gap: 4rem;
}

.footer-info {
  flex: 1;
  min-width: 280px;
  display: flex;
  flex-direction: column;
}

.footer-logo {
  font-size: 1.2rem;
  font-weight: 700;
  margin-bottom: 1rem;
  color: #FFFFFF;
}

.slogan {
  font-size: 0.95rem;
  color: #CCCCCC;
  font-weight: 400;
  font-style: normal;
  margin-bottom: 1.5rem;
  line-height: 1.5;
  word-break: keep-all;
}

address {
  font-style: normal;
  color: #888;
  line-height: 1.6;
}

.copyright {
  margin-top: 0.8rem;
  font-size: 0.8rem;
  color: #666;
}

.footer-links {
  display: flex;
  gap: 4rem;
  flex-wrap: wrap;
}

.link-column h4 {
  font-size: 0.95rem;
  font-weight: 700;
  color: #FFFFFF;
  margin-bottom: 1.2rem;
}

.link-column ul {
  list-style: none;
  padding: 0;
}

.link-column li {
  margin-bottom: 1.2rem;
  display: flex;
  flex-direction: column;
  gap: 4px;
}

.link-column a {
  text-decoration: none;
  color: #CCCCCC;
  font-weight: 500;
  transition: color 0.2s;
}

.link-column a:hover {
  color: #FFFFFF;
  text-decoration: underline;
  text-underline-offset: 4px;
}

.link-desc {
  font-size: 0.8rem;
  color: #666;
}

/* Mobile Responsive Adjustments */
@media (max-width: 768px) {
  /* Footer Layout Update */
  .footer-top {
    flex-direction: column;
    gap: 3rem;
  }
  .footer-links {
    gap: 2.5rem;
    flex-direction: column;
  }

  /* 1. Header & Logo Resizing */
  header {
    padding: 0.8rem 1rem; /* 모바일 헤더 패딩 축소 */
  }
  
  .title {
    font-size: 1rem; /* 타이틀 폰트 축소 */
  }
  
  .title img {
    height: 20px; /* 로고 이미지 높이 축소 (28px -> 20px) */
  }
  
  .back-button {
    font-size: 0.8rem;
    padding: 0.4rem 0.8rem;
  }

  /* 2. Main Layout Spacing (공간 확보) */
  main {
    padding: 2rem 1rem; /* 좌우 여백을 줄여 컨텐츠 공간 확보 */
  }

  .control-group {
    padding: 1.5rem 1rem; /* 카드 내부 패딩을 줄여 버튼 공간 확보 */
  }

  /* 3. Keypad Resizing */
  .keypad-grid {
    gap: 8px; /* 버튼 사이 간격 축소 */
  }

  .key-button {
    font-size: 1.2rem !important; /* 버튼 글씨 크기 축소 */
    border-radius: 8px !important; /* 모서리 둥글기 약간 축소 */
  }
}