:root {
  --bg: #ffffff;
  --fg: #1a1a1a;
  --muted: #666666;
  --card: #f8f9fa;
  --accent: #0066cc;
  --border: #e1e5e9;
  --shadow: rgba(0, 0, 0, 0.1);
  --error-bg: #fee;
  --error-color: #c33;
  --info-bg: #e8f4fd;
  --info-color: #0066cc;
}

@media (prefers-color-scheme: dark) {
  :root {
    --bg: #0b0c10;
    --fg: #e8e8e8;
    --muted: #9aa0a6;
    --card: #15171c;
    --accent: #4da3ff;
    --border: #2a2f36;
    --shadow: rgba(0, 0, 0, 0.25);
    --error-bg: #3b1e23;
    --error-color: #ffb3bd;
    --info-bg: #1e2f3b;
    --info-color: #b3d8ff;
  }
}

* { box-sizing: border-box; }
html, body { margin:0; padding:0; background:var(--bg); color:var(--fg); font-family: system-ui, -apple-system, Segoe UI, Roboto, "Helvetica Neue", Arial, "Noto Sans", "PingFang SC", "Hiragino Sans GB", "Microsoft YaHei", sans-serif; transition: background-color 0.3s ease, color 0.3s ease; }
.container { max-width: 860px; margin: 0 auto; padding: 20px; }
header { display:flex; align-items:center; justify-content: space-between; gap:12px; padding: 16px 0; border-bottom: 1px solid var(--border); margin-bottom: 24px; }
header h1 { font-size: 24px; margin: 0; font-weight: 700; letter-spacing: -0.5px; }
nav a { color: var(--fg); text-decoration:none; margin-right:16px; opacity:.8; font-weight: 500; transition: all 0.3s ease; }
nav a:hover { opacity:1; color: var(--accent); }
h2 { font-size: 1.5rem; margin: 0 0 16px 0; font-weight: 600; color: var(--fg); }
h3 { font-size: 1.25rem; margin: 0 0 12px 0; font-weight: 600; color: var(--fg); }

/* Enhanced spacing and typography */
body {
  line-height: 1.6;
  font-size: 16px;
  font-weight: 400;
}

section {
  margin-bottom: 24px;
}

/* Enhanced form styling */
.form-group {
  margin-bottom: 20px;
}

label {
  font-weight: 600;
  color: var(--fg);
  margin-bottom: 8px;
  font-size: 0.95rem;
}

/* Enhanced button group styling */
.btn-group {
  display: flex;
  gap: 8px;
  flex-wrap: wrap;
  margin-top: 8px;
}

.btn-group .btn.small {
  flex: 0 1 auto;
  min-width: 80px;
  max-width: 120px;
  white-space: nowrap;
  padding: 8px 12px;
  font-size: 13px;
}

@media (max-width: 768px) {
  .btn-group .btn.small {
    flex: 0 0 auto;
    min-width: 70px;
    max-width: 90px;
    padding: 6px 8px;
    font-size: 11px;
  }
}

@media (max-width: 480px) {
  .btn-group {
    gap: 4px;
  }
  
  .btn-group .btn.small {
    flex: 0 0 auto;
    min-width: 60px;
    max-width: 80px;
    padding: 6px 8px;
    font-size: 11px;
    margin-bottom: 0;
  }
}

/* Enhanced navigation styling */
nav {
  display: flex;
  gap: 8px;
}

nav a {
  padding: 8px 16px;
  border-radius: 20px;
  background: var(--card);
  border: 1px solid var(--border);
  transition: all 0.3s ease;
  margin: 0;
}

nav a:hover {
  background: var(--accent);
  color: white;
  transform: translateY(-1px);
}

/* Enhanced card styling */
.card {
  background: var(--card);
  border-radius: 16px;
  padding: 32px;
  box-shadow: 0 8px 32px var(--shadow);
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

/* Animated form background with DATA/background.jfif */
.animated-form {
  position: relative;
  background: var(--card);
  overflow: hidden;
}

.animated-form::before {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 100%;
  background-image: url('/static/background.jfif');
  background-size: 100% auto;
  background-position: center top;
  background-repeat: no-repeat;
  pointer-events: none;
  z-index: 0;
}

.animated-form::after {
  content: '';
  position: absolute;
  top: 0;
  left: 0;
  right: 0;
  height: 100%;
  background: linear-gradient(
    to bottom,
    rgba(248, 249, 250, 0.4) 0%,
    rgba(248, 249, 250, 0.55) 26%,
    rgba(248, 249, 250, 0.7) 46%,
    rgba(248, 249, 250, 0.83) 75%,
    rgba(248, 249, 250, 1) 100%
  );
  pointer-events: none;
  z-index: 1;
}

/* Dark mode support for animated form background */
@media (prefers-color-scheme: dark) {
  .animated-form::after {
    background: linear-gradient(
      to bottom,
    rgba(21, 23, 28, 0.4) 0%,
    rgba(21, 23, 28, 0.55) 26%,
    rgba(21, 23, 28, 0.7) 46%,
    rgba(21, 23, 28, 0.83) 75%,
    rgba(21, 23, 28, 1) 100%
    );
  }
  
  /* Dark mode datetime picker styling */
  input[type=datetime-local] {
    background: var(--card);
    border-color: var(--border);
    color: var(--fg);
  }
  
  input[type=datetime-local]:focus {
    border-color: var(--accent);
    box-shadow: 0 0 0 3px rgba(77, 163, 255, 0.1);
  }
  
  /* Ensure proper contrast for datetime picker controls */
  input[type=datetime-local]::-webkit-calendar-picker-indicator {
    filter: invert(0.8) brightness(1.2) contrast(1.2);
  }
}

.animated-form > * {
  position: relative;
  z-index: 2;
}

.card:hover {
  box-shadow: 0 12px 48px var(--shadow);
  transform: translateY(-2px);
}

/* Enhanced responsive header */
@media (max-width: 768px) {
  header {
    flex-direction: column;
    align-items: center;
    text-align: center;
    gap: 16px;
  }
  
  header h1 {
    font-size: 22px;
  }
  
  nav {
    flex-direction: row;
    justify-content: center;
    flex-wrap: wrap;
  }
  
  nav a {
    margin: 4px;
    font-size: 14px;
  }
}
.card { background: var(--card); border-radius: 14px; padding: 20px; box-shadow: 0 4px 12px var(--shadow); transition: all 0.3s ease; }
.card:hover { box-shadow: 0 6px 20px var(--shadow); }
label { display:block; margin: 12px 0 6px; font-weight:600; color: var(--fg); }
input[type=text], input[type=email], input[type=file], input[type=datetime-local], textarea { 
  width: 100%; 
  padding: 12px 14px; 
  border-radius: 10px; 
  border: 1px solid var(--border); 
  background: var(--bg); 
  color: var(--fg);
  transition: border-color 0.3s ease, box-shadow 0.3s ease;
  cursor: pointer;
}
input[type=text]:focus, input[type=email]:focus, input[type=datetime-local]:focus, textarea:focus {
  outline: none;
  border-color: var(--accent);
  box-shadow: 0 0 0 3px rgba(0, 102, 204, 0.1);
}
textarea { resize: vertical; min-height: 100px; }
.btn { 
  display:inline-block; 
  padding: 12px 20px; 
  border-radius: 10px; 
  border: 1px solid var(--border); 
  background: var(--accent); 
  color: white; 
  font-weight:600; 
  text-decoration:none; 
  cursor:pointer;
  transition: all 0.3s ease;
}
.btn:hover { 
  transform: translateY(-1px); 
  box-shadow: 0 4px 12px rgba(0, 102, 204, 0.3); 
}
.btn.ghost { 
  background: transparent; 
  color: var(--accent); 
  border-color: var(--accent);
}
.btn.ghost:hover {
  background: var(--accent);
  color: white;
}
.btn.small { padding:8px 12px; font-size: 13px; }
.row { display:flex; align-items:center; gap:8px; margin: 4px 0; }
input[type=datetime-local] {
  position: relative;
  z-index: 1;
  cursor: pointer;
  width: auto;
  min-width: 200px;
  max-width: 360px;
  background: var(--bg);
  color: var(--fg);
}

/* Dark mode for datetime picker controls */
@media (prefers-color-scheme: dark) {
  input[type=datetime-local]::-webkit-calendar-picker-indicator {
    filter: invert(1) brightness(1.5) contrast(1.2);
  }
  
  /* Firefox dark mode styling */
  input[type=datetime-local]::-moz-calendar-picker-indicator {
    filter: invert(1) brightness(1.5) contrast(1.2);
  }
}
.row.end { justify-content: flex-end; }
.row.gap { gap: 6px; flex-wrap: wrap; }
.flash-wrap { margin-bottom: 10px; }
.flash { padding:10px 12px; border-radius: 8px; border: 1px solid; }
.flash.error { background: var(--error-bg); color: var(--error-color); border-color: var(--error-color); }
.flash.info { background: var(--info-bg); color: var(--info-color); border-color: var(--info-color); }
.muted { color: var(--muted); font-size: 14px; }
.key { background: var(--card); padding:10px 12px; border-radius: 8px; overflow:auto; border: 1px solid var(--border); }
footer.footer { margin-top: 18px; opacity:.7; }
.message { background: var(--card); padding: 16px; border-radius: 10px; line-height: 1.6; border: 1px solid var(--border); }
.image-wrap { margin-top: 12px; }
.image-wrap img { max-width: 100%; height: auto; border-radius: 10px; border:1px solid var(--border); }
.force-link { color: var(--accent); text-decoration: underline; }

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

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

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.05); }
  100% { transform: scale(1); }
}

@keyframes shake {
  0%, 100% { transform: translateX(0); }
  25% { transform: translateX(-5px); }
  75% { transform: translateX(5px); }
}

.animated-card {
  animation: fadeInUp 0.6s ease-out;
}

.animated-form {
  animation: slideIn 0.5s ease-out;
}

.btn:active {
  transform: scale(0.95);
}

.btn:hover {
  animation: pulse 0.3s ease-in-out;
}

.flash {
  animation: slideIn 0.3s ease-out;
}

.error {
  animation: shake 0.5s ease-in-out;
}

/* Smooth transitions for all interactive elements */
.card, .btn, input, textarea, .stat-item {
  transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);
}

/* Hover effects */
.stat-item:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 25px var(--shadow);
}

input:hover, textarea:hover {
  border-color: var(--accent);
}

/* Enhanced stat item styling */
.stat-item {
  background: var(--card);
  padding: 2rem;
  border-radius: 12px;
  text-align: center;
  border: 1px solid var(--border);
  transition: all 0.3s ease;
}

.stat-number {
  font-size: 2.5rem;
  font-weight: bold;
  margin-bottom: 0.5rem;
}

.stat-label {
  font-size: 1.1rem;
  color: var(--muted);
  margin-bottom: 0.25rem;
}

.percentage {
  font-size: 0.9em;
  color: var(--muted);
  opacity: 0.8;
}

@media (max-width: 768px) {
  .stat-item {
    padding: 1.5rem;
  }
  
  .stat-number {
    font-size: 2rem;
  }
  
  .stat-label {
    font-size: 1rem;
  }
}

/* Loading animation */
.loading {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 3px solid var(--border);
  border-radius: 50%;
  border-top-color: var(--accent);
  animation: spin 1s ease-in-out infinite;
}

@keyframes spin {
  to { transform: rotate(360deg); }
}

/* Success animations */
@keyframes successPulse {
  0% {
    transform: scale(1);
    opacity: 0.8;
  }
  50% {
    transform: scale(1.1);
    opacity: 1;
  }
  100% {
    transform: scale(1);
    opacity: 0.8;
  }
}

@keyframes capsuleFloat {
  0% {
    transform: translateY(0) scale(1);
    opacity: 0;
  }
  50% {
    transform: translateY(-20px) scale(1.1);
    opacity: 1;
  }
  100% {
    transform: translateY(0) scale(1);
    opacity: 1;
  }
}

@keyframes capsuleOpen {
  0% {
    transform: scale(0.8) rotate(-5deg);
    opacity: 0;
  }
  50% {
    transform: scale(1.1) rotate(5deg);
    opacity: 1;
  }
  100% {
    transform: scale(1) rotate(0deg);
    opacity: 1;
  }
}

.success-animation {
  animation: successPulse 0.6s ease-in-out;
}

.capsule-success {
  animation: capsuleFloat 1s ease-out;
}

.capsule-open {
  animation: capsuleOpen 0.8s ease-out;
}

.success-overlay {
  position: fixed;
  top: 0;
  left: 0;
  width: 100%;
  height: 100%;
  background: rgba(0, 0, 0, 0.8);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 1000;
  opacity: 0;
  visibility: hidden;
  transition: all 0.3s ease;
}

.success-overlay.show {
  opacity: 1;
  visibility: visible;
}

.success-message {
  background: var(--card);
  padding: 40px;
  border-radius: 20px;
  text-align: center;
  box-shadow: 0 10px 40px var(--shadow);
  transform: scale(0.8);
  transition: transform 0.3s ease;
}

.success-overlay.show .success-message {
  transform: scale(1);
}

.success-icon {
  font-size: 4rem;
  margin-bottom: 20px;
  animation: successPulse 1s ease-in-out infinite;
}

.success-title {
  font-size: 1.5rem;
  font-weight: 600;
  color: var(--accent);
  margin-bottom: 10px;
}

.success-text {
  color: var(--muted);
  font-size: 1.1rem;
}

/* Mobile responsive improvements */
@media (max-width: 768px) {
  .container { padding: 12px; }
  header { 
    flex-direction: column; 
    align-items: flex-start; 
    gap: 8px;
  }
  header h1 { font-size: 20px; margin: 4px 0; }
  nav a { margin-right: 8px; font-size: 14px; }
  .card { padding: 16px; margin: 8px 0; }
  .row { flex-direction: column; align-items: stretch; gap: 8px; }
  .row.end { align-items: stretch; }
  input[type=text], input[type=email], textarea { font-size: 16px; }
  .btn { width: 100%; margin: 4px 0; }
  .stats-grid {
    grid-template-columns: 1fr !important;
    gap: 1rem;
  }
  .stat-item { padding: 1rem; }
  .stat-number { font-size: 1.8rem !important; }
}

@media (max-width: 480px) {
  header { 
    flex-direction: column; 
    align-items: center; 
    text-align: center;
  }
  nav { margin-top: 8px; }
  nav a { 
    display: inline-block; 
    margin: 4px 6px; 
    padding: 6px 12px; 
    background: var(--card); 
    border-radius: 20px;
    font-size: 13px;
  }
}