:root {
  --bg-dark: #0a0a0f;
  --bg-gradient-start: #0f0f1a;
  --bg-gradient-end: #1a1a2e;
  --text-primary: #ffffff;
  --text-secondary: #b4b4c8;
  --accent-primary: #3b82f6;
  --accent-secondary: #60a5fa;
  --accent-glow: rgba(59, 130, 246, 0.3);
  --glass-bg: rgba(255, 255, 255, 0.05);
  --glass-border: rgba(255, 255, 255, 0.1);
  --glass-hover: rgba(255, 255, 255, 0.08);
  --shadow-lg: 0 20px 60px rgba(0, 0, 0, 0.5);
  --shadow-xl: 0 25px 80px rgba(0, 0, 0, 0.6);
  --font-main: -apple-system, BlinkMacSystemFont, 'Segoe UI', 'PingFang SC', 'Microsoft YaHei', sans-serif;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 16px;
  --radius-xl: 20px;
}

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

body {
  font-family: var(--font-main);
  background: var(--bg-dark);
  color: var(--text-primary);
  overflow: hidden;
  height: 100vh;
  width: 100vw;
  user-select: none;
  -webkit-user-select: none;
  -webkit-user-drag: none;
}

#app {
  height: 100%;
  width: 100%;
}

/* ===== Intro Overlay ===== */
.intro-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: linear-gradient(135deg, var(--bg-gradient-start) 0%, var(--bg-gradient-end) 100%);
  z-index: 9999;
  display: flex;
  justify-content: center;
  align-items: center;
  transition: opacity 1s ease, visibility 1s ease;
}

.intro-overlay.hidden {
  opacity: 0;
  visibility: hidden;
  pointer-events: none;
}

.intro-content {
  text-align: center;
  width: 100%;
  max-width: 800px;
  padding: 2rem;
  margin: 0 auto;
}

.intro-text-container {
  min-height: 180px;
  display: flex;
  flex-direction: column;
  justify-content: center;
  align-items: center;
  gap: 1.2rem;
  position: absolute;
  top: 35%;
  left: 50%;
  transform: translateX(-50%);
  width: 100%;
  z-index: 2;
}

.intro-text {
  font-size: 1.3rem;
  font-weight: 600;
  opacity: 0;
  transform: translateY(20px);
  transition: opacity 0.8s ease, transform 0.8s ease;
  letter-spacing: 0.5px;
  line-height: 1.6;
  white-space: nowrap;
  overflow: hidden;
  text-overflow: ellipsis;
  max-width: 100%;
  color: #e0e0e0;
  user-select: none;
}

.intro-text.visible {
  opacity: 1;
  transform: translateY(0);
}

.click-to-continue {
  opacity: 0;
  transition: opacity 0.5s ease;
  font-size: 1rem;
  color: var(--text-secondary);
  font-weight: 400;
  letter-spacing: 1px;
  text-align: center;
  width: 100%;
  position: absolute;
  top: 50%;
  left: 0;
  transform: translateY(-50%);
  z-index: 2;
  user-select: none;
}

.click-to-continue.visible {
  opacity: 1;
}

.click-to-continue.visible span {
  display: inline-block;
  animation: breathe 2s infinite ease-in-out;
}

@keyframes breathe {

  0%,
  100% {
    opacity: 0.4;
    transform: scale(0.98);
  }

  50% {
    opacity: 1;
    transform: scale(1.02);
  }
}

/* ===== Wall Container ===== */
.wall-container {
  width: 100%;
  height: 100%;
  background: radial-gradient(circle at 50% 50%, var(--bg-gradient-start) 0%, var(--bg-dark) 100%);
  position: relative;
  opacity: 0;
  transition: opacity 1s ease;
}

.wall-container.visible {
  opacity: 1;
}

.wall-container.hidden {
  display: none;
}

/* ===== Header ===== */
.wall-header {
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  padding: 1.5rem 2.5rem;
  display: flex;
  justify-content: flex-end;
  align-items: center;
  z-index: 100;
  background: linear-gradient(180deg, rgba(10, 10, 15, 0.8) 0%, transparent 100%);
  backdrop-filter: blur(10px);
  -webkit-user-drag: none;
}

.controls {
  display: flex;
  gap: 0.75rem;
}

.control-btn {
  width: 44px;
  height: 44px;
  border-radius: 50%;
  border: none;
  background: var(--glass-bg);
  backdrop-filter: blur(10px);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  font-size: 1.1rem;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
  position: relative;
  overflow: hidden;
  user-select: none;
}

.control-btn:hover {
  background: var(--glass-hover);
  transform: translateY(-2px);
}

.control-btn:active {
  transform: translateY(0) scale(0.95);
}

.control-btn i {
  position: relative;
  z-index: 1;
  transition: transform 0.3s ease;
}

.control-btn:hover i {
  transform: scale(1.1);
}

/* Music button playing state */
.control-btn.playing i {
  animation: music-pulse 1.8s infinite ease-in-out;
}

@keyframes music-pulse {

  0%,
  100% {
    transform: scale(1);
  }

  50% {
    transform: scale(1.15);
  }
}

/* ===== Card Area ===== */
.card-area {
  width: 100%;
  height: 100%;
  position: relative;
  overflow: hidden;
  z-index: 10;
}

/* ===== Card ===== */
.card {
  position: absolute;
  width: 280px;
  min-height: 180px;
  padding: 1.5rem;
  background: rgba(255, 255, 255, 0.15);
  backdrop-filter: blur(20px);
  border: 2px solid rgba(255, 255, 255, 0.4);
  border-radius: var(--radius-lg);
  box-shadow: var(--shadow-lg);
  color: var(--text-primary);
  cursor: grab;
  touch-action: none;
  user-select: none;
  transition: box-shadow 0.3s ease, border-color 0.3s ease;
  z-index: 1000;
}

.card:hover {
  box-shadow: var(--shadow-xl), 0 0 30px var(--accent-glow);
  z-index: 1100 !important;
}

.card:active {
  cursor: grabbing;
  box-shadow: var(--shadow-xl), 0 0 40px var(--accent-glow);
  z-index: 1200 !important;
}

.card-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1rem;
  font-size: 0.85rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.card-header span {
  display: flex;
  align-items: center;
  gap: 0.4rem;
}

.card-body {
  font-size: 1.05rem;
  line-height: 1.6;
  margin: 1rem 0;
  color: var(--text-primary);
  font-weight: 400;
}

.card-footer {
  font-size: 0.75rem;
  color: var(--text-secondary);
  text-align: right;
  margin-top: 1rem;
  opacity: 0.7;
}

/* ===== Modal ===== */
.modal-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.7);
  backdrop-filter: blur(8px);
  z-index: 10000;
  display: flex;
  justify-content: center;
  align-items: center;
  opacity: 1;
  transition: opacity 0.3s ease;
}

.modal-overlay.hidden {
  opacity: 0;
  pointer-events: none;
}

.modal {
  background: linear-gradient(135deg, rgba(26, 26, 46, 0.95) 0%, rgba(15, 15, 26, 0.95) 100%);
  backdrop-filter: blur(20px);
  padding: 2rem;
  border-radius: var(--radius-xl);
  border: 1px solid var(--glass-border);
  width: 90%;
  max-width: 480px;
  box-shadow: var(--shadow-xl);
  animation: modal-appear 0.3s ease-out;
}

@keyframes modal-appear {
  from {
    opacity: 0;
    transform: scale(0.9) translateY(-20px);
  }

  to {
    opacity: 1;
    transform: scale(1) translateY(0);
  }
}

.modal-header {
  display: flex;
  justify-content: space-between;
  align-items: center;
  margin-bottom: 1.5rem;
  font-size: 1.5rem;
}

.modal-header h2 {
  font-size: 1.5rem;
  font-weight: 600;
  color: #e0e0e0;
}

.close-btn {
  width: 36px;
  height: 36px;
  border-radius: 50%;
  border: none;
  background: var(--glass-bg);
  color: var(--text-secondary);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: all 0.2s ease;
}

.close-btn:hover {
  background: var(--glass-hover);
  color: var(--text-primary);
  transform: rotate(90deg);
}

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

.form-group label {
  display: block;
  margin-bottom: 0.5rem;
  font-size: 0.9rem;
  color: var(--text-secondary);
  font-weight: 500;
}

.form-group input,
.form-group textarea {
  width: 100%;
  padding: 0.875rem 1rem;
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  border-radius: var(--radius-md);
  color: var(--text-primary);
  font-family: var(--font-main);
  font-size: 0.95rem;
  transition: all 0.2s ease;
}

.form-group input:focus,
.form-group textarea:focus {
  outline: none;
  border-color: var(--accent-primary);
  background: rgba(255, 255, 255, 0.08);
  box-shadow: 0 0 0 3px var(--accent-glow);
}

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

.form-actions {
  display: flex;
  justify-content: flex-end;
  gap: 0.75rem;
  margin-top: 1.5rem;
}

.btn {
  padding: 0.75rem 1.5rem;
  border-radius: var(--radius-md);
  border: none;
  cursor: pointer;
  font-family: var(--font-main);
  font-weight: 500;
  font-size: 0.95rem;
  transition: all 0.2s ease;
  display: flex;
  align-items: center;
  gap: 0.5rem;
}

.btn-secondary {
  background: transparent;
  color: var(--text-secondary);
  border: 1px solid var(--glass-border);
}

.btn-secondary:hover {
  background: var(--glass-bg);
  color: var(--text-primary);
}

.btn-primary {
  background: transparent;
  color: #d0d0d0;
  border: 1px solid var(--glass-border);
}

.btn-primary:hover {
  background: var(--glass-bg);
  color: var(--text-primary);
}

.btn-primary:active {
  transform: translateY(0);
}

/* ===== Toast ===== */
.toast {
  position: fixed;
  bottom: 2rem;
  left: 50%;
  transform: translateX(-50%) translateY(100px);
  background: var(--glass-bg);
  border: 1px solid var(--glass-border);
  color: var(--text-primary);
  padding: 1rem 1.75rem;
  border-radius: var(--radius-lg);
  backdrop-filter: blur(10px);
  box-shadow: var(--shadow-lg);
  z-index: 11000;
  font-size: 0.95rem;
  font-weight: 500;
  transition: transform 0.3s cubic-bezier(0.4, 0, 0.2, 1), opacity 0.3s ease;
  opacity: 0;
  display: flex;
  align-items: center;
  gap: 0.75rem;
}

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

.toast.hidden {
  display: none;
}

.toast i {
  font-size: 1.2rem;
}

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

  .card {
    width: 240px;
    min-height: 160px;
    padding: 1.25rem;
  }

  .modal {
    padding: 1.5rem;
  }
}

/* ===== Footer ===== */
.wall-footer {
  position: absolute;
  bottom: 1rem;
  right: 1.5rem;
  font-size: 0.8rem;
  color: var(--text-secondary);
  z-index: 100;
  user-select: none;
}

.wall-footer a {
  color: var(--text-secondary);
  text-decoration: none;
}

.wall-footer a.author {
  color: #d0d0d0;
  transition: color 0.2s ease;
  font-size: 0.9rem;
}

.wall-footer a.author:hover {
  color: var(--text-primary);
}