/* ===== Alio-Letter Global Styles ===== */
/* Mobile-First / Pretendard / Blue Trust Tone */

@import url('https://cdn.jsdelivr.net/gh/orioncactus/pretendard@v1.3.9/dist/web/variable/pretendardvariable-dynamic-subset.min.css');

:root {
  --primary: #2563EB;
  --primary-dark: #1D4ED8;
  --primary-light: #DBEAFE;
  --primary-50: #EFF6FF;
  --success: #16A34A;
  --success-light: #DCFCE7;
  --error: #DC2626;
  --error-light: #FEE2E2;
  --warning: #F59E0B;
  --warning-light: #FEF3C7;
  --gray-50: #F9FAFB;
  --gray-100: #F3F4F6;
  --gray-200: #E5E7EB;
  --gray-300: #D1D5DB;
  --gray-400: #9CA3AF;
  --gray-500: #6B7280;
  --gray-600: #4B5563;
  --gray-700: #374151;
  --gray-800: #1F2937;
  --gray-900: #111827;
  --radius: 8px;
  --radius-lg: 12px;
  --shadow-sm: 0 1px 2px rgba(0,0,0,0.05);
  --shadow: 0 1px 3px rgba(0,0,0,0.1), 0 1px 2px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 6px rgba(0,0,0,0.07), 0 2px 4px rgba(0,0,0,0.06);
  --shadow-lg: 0 10px 15px rgba(0,0,0,0.1), 0 4px 6px rgba(0,0,0,0.05);
  --max-width: 720px;
  --transition: 0.2s ease;
}

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

html {
  font-size: 16px;
  -webkit-text-size-adjust: 100%;
}

body {
  font-family: 'Pretendard Variable', Pretendard, -apple-system, BlinkMacSystemFont, 'Segoe UI', Roboto, sans-serif;
  color: var(--gray-800);
  background: #fff;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ===== Layout ===== */
.container {
  width: 100%;
  max-width: var(--max-width);
  margin: 0 auto;
  padding: 0 20px;
}

.container-wide {
  max-width: 960px;
}

/* ===== Navigation ===== */
.nav {
  position: sticky;
  top: 0;
  background: rgba(255,255,255,0.95);
  backdrop-filter: blur(8px);
  border-bottom: 1px solid var(--gray-200);
  z-index: 100;
  padding: 14px 0;
}

.nav .container {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.nav-logo {
  font-size: 1.25rem;
  font-weight: 700;
  color: var(--primary);
  text-decoration: none;
  letter-spacing: -0.02em;
}

.nav-logo span {
  color: var(--gray-800);
}

.nav-cta {
  display: inline-flex;
  align-items: center;
  padding: 8px 18px;
  background: var(--primary);
  color: #fff;
  text-decoration: none;
  border-radius: var(--radius);
  font-size: 0.875rem;
  font-weight: 600;
  transition: background var(--transition);
}

.nav-cta:hover {
  background: var(--primary-dark);
}

/* ===== Footer ===== */
.footer {
  border-top: 1px solid var(--gray-200);
  padding: 32px 0;
  margin-top: 64px;
  color: var(--gray-500);
  font-size: 0.8125rem;
  line-height: 1.8;
}

/* ===== Buttons ===== */
.btn {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  padding: 12px 28px;
  border: none;
  border-radius: var(--radius);
  font-size: 1rem;
  font-weight: 600;
  cursor: pointer;
  transition: all var(--transition);
  text-decoration: none;
  line-height: 1.4;
}

.btn-primary {
  background: var(--primary);
  color: #fff;
}

.btn-primary:hover {
  background: var(--primary-dark);
  transform: translateY(-1px);
  box-shadow: var(--shadow-md);
}

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

.btn-primary:disabled {
  background: var(--gray-300);
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

.btn-outline {
  background: #fff;
  color: var(--primary);
  border: 1.5px solid var(--primary);
}

.btn-outline:hover {
  background: var(--primary-50);
}

.btn-full {
  width: 100%;
}

.btn-lg {
  padding: 14px 32px;
  font-size: 1.0625rem;
}

/* ===== Form Elements ===== */
.form-group {
  margin-bottom: 24px;
}

.form-label {
  display: block;
  font-size: 0.9375rem;
  font-weight: 600;
  color: var(--gray-700);
  margin-bottom: 6px;
}

.form-label .required {
  color: var(--error);
  margin-left: 2px;
}

.form-input,
.form-textarea {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 1rem;
  font-family: inherit;
  color: var(--gray-800);
  background: #fff;
  transition: border-color var(--transition), box-shadow var(--transition);
  outline: none;
}

.form-input:focus,
.form-textarea:focus {
  border-color: var(--primary);
  box-shadow: 0 0 0 3px rgba(37,99,235,0.1);
}

.form-input::placeholder,
.form-textarea::placeholder {
  color: var(--gray-400);
}

.form-input.readonly {
  background: var(--gray-100);
  color: var(--gray-500);
  cursor: not-allowed;
}

.form-textarea {
  min-height: 140px;
  resize: vertical;
  line-height: 1.6;
}

.form-hint {
  margin-top: 6px;
  font-size: 0.8125rem;
  color: var(--gray-500);
  line-height: 1.6;
}

.form-hint-box {
  margin-top: 8px;
  padding: 12px 14px;
  background: var(--gray-50);
  border: 1px solid var(--gray-200);
  border-radius: var(--radius);
  font-size: 0.8125rem;
  color: var(--gray-600);
  line-height: 1.7;
}

.form-error {
  margin-top: 6px;
  font-size: 0.8125rem;
  color: var(--error);
  display: none;
}

.form-group.has-error .form-input,
.form-group.has-error .form-textarea {
  border-color: var(--error);
}

.form-group.has-error .form-error {
  display: block;
}

/* Checkbox */
.form-check {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  cursor: pointer;
}

.form-check input[type="checkbox"] {
  width: 18px;
  height: 18px;
  margin-top: 2px;
  flex-shrink: 0;
  accent-color: var(--primary);
}

.form-check-label {
  font-size: 0.875rem;
  color: var(--gray-600);
  line-height: 1.5;
}

/* ===== Alert / Message ===== */
.alert {
  padding: 14px 16px;
  border-radius: var(--radius);
  font-size: 0.9375rem;
  line-height: 1.5;
  display: none;
}

.alert.show {
  display: block;
}

.alert-success {
  background: var(--success-light);
  color: #166534;
  border: 1px solid #BBF7D0;
}

.alert-error {
  background: var(--error-light);
  color: #991B1B;
  border: 1px solid #FECACA;
}

.alert-info {
  background: var(--primary-light);
  color: #1E40AF;
  border: 1px solid #BFDBFE;
}

/* ===== Loading Spinner ===== */
.spinner {
  display: inline-block;
  width: 20px;
  height: 20px;
  border: 2.5px solid rgba(255,255,255,0.3);
  border-top-color: #fff;
  border-radius: 50%;
  animation: spin 0.6s linear infinite;
  margin-right: 8px;
}

.spinner-dark {
  border-color: rgba(0,0,0,0.1);
  border-top-color: var(--primary);
}

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

/* ===== Section Helpers ===== */
.section {
  padding: 48px 0;
}

.section-title {
  font-size: 1.5rem;
  font-weight: 700;
  color: var(--gray-900);
  margin-bottom: 8px;
  letter-spacing: -0.02em;
}

.section-subtitle {
  font-size: 1rem;
  color: var(--gray-500);
  margin-bottom: 32px;
}

/* ===== Card ===== */
.card {
  background: #fff;
  border: 1px solid var(--gray-200);
  border-radius: var(--radius-lg);
  padding: 24px;
  transition: box-shadow var(--transition);
}

.card:hover {
  box-shadow: var(--shadow-md);
}

/* ===== Utility ===== */
.text-center { text-align: center; }
.text-muted { color: var(--gray-500); }
.text-sm { font-size: 0.875rem; }
.mt-4 { margin-top: 16px; }
.mt-8 { margin-top: 32px; }
.mb-4 { margin-bottom: 16px; }
.mb-8 { margin-bottom: 32px; }
.hidden { display: none; }

/* ===== Filter UI (checkbox-grid, form-radio) ===== */
.checkbox-grid {
  display: flex;
  flex-wrap: wrap;
  gap: 8px 12px;
}

.form-checkbox {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  font-size: 0.875rem;
  color: var(--gray-700);
}

.form-checkbox input[type="checkbox"] {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  accent-color: var(--primary);
}

.radio-group {
  display: flex;
  align-items: center;
  flex-wrap: wrap;
  gap: 8px 16px;
}

.form-radio {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  cursor: pointer;
  font-size: 0.875rem;
  color: var(--gray-700);
}

.form-radio input[type="radio"] {
  width: 16px;
  height: 16px;
  flex-shrink: 0;
  accent-color: var(--primary);
}

.form-label-sm {
  font-size: 0.8125rem;
  color: var(--gray-500);
}

.form-select {
  width: 100%;
  padding: 10px 14px;
  border: 1.5px solid var(--gray-300);
  border-radius: var(--radius);
  font-size: 0.9375rem;
  color: var(--gray-800);
  background: #fff;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='8' viewBox='0 0 12 8'%3E%3Cpath d='M1 1l5 5 5-5' stroke='%236B7280' stroke-width='1.5' fill='none' stroke-linecap='round'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 40px;
  cursor: pointer;
  transition: border-color var(--transition);
}

.form-select:focus {
  outline: none;
  border-color: var(--primary);
}

.mt-2 { margin-top: 8px; }

/* ===== Responsive ===== */
@media (min-width: 640px) {
  .container { padding: 0 32px; }
  .section { padding: 64px 0; }
  .section-title { font-size: 1.75rem; }
}