/* 
 * CSS Design System - Hệ thống Nộp Bài Hợp Nhất
 * Nguyễn Toàn Center
 * File: style.css
 */

:root {
  --primary: #0E5E6F;
  --primary-light: rgba(14, 94, 111, 0.1);
  --primary-glow: rgba(14, 94, 111, 0.15);
  --accent: #2FB8AC;
  --accent-glow: rgba(47, 184, 172, 0.25);
  
  --bg: #F4FBFA;
  --bg-gradient: linear-gradient(135deg, #F4FBFA 0%, #E8F5F3 100%);
  --card-bg: rgba(255, 255, 255, 0.85);
  
  --text: #0B2B33;
  --muted: #5A6B70;
  --border: #D7EFEC;
  --border-focus: #2FB8AC;
  
  --danger: #D32F2F;
  --danger-bg: rgba(211, 47, 47, 0.06);
  --danger-border: rgba(211, 47, 47, 0.2);
  
  --ok: #2E7D32;
  --ok-bg: rgba(46, 125, 50, 0.08);
  
  --shadow-sm: 0 4px 12px rgba(14, 94, 111, 0.04);
  --shadow-md: 0 12px 30px rgba(14, 94, 111, 0.08);
  --shadow-lg: 0 24px 64px rgba(14, 94, 111, 0.14);
  
  --transition: all 0.25s cubic-bezier(0.4, 0, 0.2, 1);
}

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

body {
  font-family: 'Inter', -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
  background: var(--bg-gradient);
  color: var(--text);
  min-height: 100vh;
  line-height: 1.5;
  padding-bottom: 60px;
}

.wrap {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px;
}

/* Header & Brand styling */
.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.brand {
  display: flex;
  align-items: center;
  gap: 16px;
}

.logo {
  width: 60px;
  height: 60px;
  border-radius: 16px;
  background: #fff;
  border: 1px solid var(--border);
  display: flex;
  align-items: center;
  justify-content: center;
  overflow: hidden;
  box-shadow: var(--shadow-sm);
}

.logo img {
  width: 100%;
  height: 100%;
  object-fit: cover;
}

h1 {
  font-family: 'Montserrat', sans-serif;
  font-size: 22px;
  font-weight: 800;
  color: var(--primary);
  letter-spacing: -0.5px;
  line-height: 1.2;
}

.sub {
  font-size: 13px;
  color: var(--muted);
  font-weight: 700;
  letter-spacing: 1px;
  margin-top: 2px;
}

/* Glassmorphism Card styling */
.card {
  border-radius: 24px;
  padding: 28px;
  transition: var(--transition);
}

.glass {
  background: var(--card-bg);
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  border: 1px solid rgba(215, 239, 236, 0.6);
  box-shadow: var(--shadow-md);
}

.card:hover {
  box-shadow: var(--shadow-lg);
  border-color: rgba(215, 239, 236, 0.9);
}

@media (max-width: 650px) {
  .card {
    padding: 20px 16px;
    border-radius: 20px;
  }
  .tab-btn {
    padding: 12px 8px;
    font-size: 14px;
  }
}

/* Segmented Tab control buttons */
.tabs-control {
  display: flex;
  background: rgba(14, 94, 111, 0.05);
  border: 1px solid var(--border);
  padding: 6px;
  border-radius: 16px;
  gap: 8px;
  margin-bottom: 24px;
}

.tab-btn {
  flex: 1;
  border: none;
  background: transparent;
  padding: 14px 18px;
  font-size: 15px;
  font-weight: 700;
  color: var(--muted);
  border-radius: 12px;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.tab-btn span {
  display: flex;
  align-items: center;
  gap: 8px;
}

.tab-btn:hover {
  color: var(--primary);
  background: rgba(14, 94, 111, 0.04);
}

.tab-btn.active {
  background: #ffffff;
  color: var(--primary);
  box-shadow: 0 4px 12px rgba(14, 94, 111, 0.08);
}

/* Form Sections */
.tab-content {
  display: none;
}

.tab-content.active {
  display: block;
  animation: fadeIn 0.3s ease;
}

.form-section-title {
  font-family: 'Montserrat', sans-serif;
  font-size: 18px;
  font-weight: 700;
  color: var(--primary);
  margin-bottom: 20px;
  padding-bottom: 8px;
  border-bottom: 2px solid var(--border);
}

/* Input Fields Styles */
label {
  display: block;
  font-size: 14px;
  font-weight: 700;
  color: var(--primary);
  margin: 18px 0 6px;
}

.required-label::after {
  content: " *";
  color: var(--danger);
}

.field-hint {
  font-size: 12.5px;
  color: var(--muted);
  margin-top: -4px;
  margin-bottom: 8px;
}

input[type="text"],
input[type="date"],
textarea {
  width: 100%;
  padding: 12px 16px;
  border-radius: 14px;
  border: 1px solid #CFE6E3;
  background: #ffffff;
  color: var(--text);
  font-size: 16px; /* iOS Safari requires >=16px to prevent zoom */
  font-family: inherit;
  outline: none;
  transition: var(--transition);
}

input::placeholder,
textarea::placeholder {
  color: #a3b8b5;
}

input:focus,
textarea:focus {
  border-color: var(--border-focus);
  box-shadow: 0 0 0 4px var(--accent-glow);
}

textarea {
  min-height: 100px;
  resize: vertical;
}

/* Grids layout */
.grid-2 {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 16px;
}

@media (max-width: 650px) {
  .grid-2 {
    grid-template-columns: 1fr;
    gap: 16px;
  }
}

/* Pill radio buttons group */
.pill-group {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  padding: 8px;
  border: 1px solid var(--border);
  border-radius: 16px;
  background: rgba(47, 184, 172, 0.04);
}

.scrollable-pills {
  max-height: 130px;
  overflow-y: auto;
}

.pill input[type="radio"],
.pill input[type="checkbox"] {
  display: none;
}

.pill span {
  display: inline-block;
  padding: 8px 14px;
  border-radius: 10px;
  border: 2px solid transparent;
  color: var(--primary);
  background: #ffffff;
  font-size: 13.5px;
  font-weight: 700;
  cursor: pointer;
  box-shadow: var(--shadow-sm);
  transition: var(--transition);
  user-select: none;
}

.pill:hover span {
  border-color: var(--border);
}

.pill input[type="radio"]:checked + span,
.pill input[type="checkbox"]:checked + span {
  background: var(--accent);
  color: #ffffff;
  box-shadow: 0 6px 15px var(--accent-glow);
  transform: translateY(-1px);
}

/* Date Pickers container styling */
.date-input-wrapper {
  position: relative;
}

.date-native-picker {
  position: absolute;
  inset: 0;
  opacity: 0.01;
  cursor: pointer;
  z-index: 2;
}

.date-icon-btn {
  position: absolute;
  right: 12px;
  top: 50%;
  transform: translateY(-50%);
  border: 1px solid var(--border);
  background: #ffffff;
  border-radius: 10px;
  padding: 10px 12px;
  font-size: 16px;
  cursor: pointer;
  z-index: 1;
  transition: var(--transition);
}

.date-icon-btn:hover {
  background: var(--primary-light);
}

#ngayDayDisplay,
#ngayTrucDisplay {
  padding-right: 52px;
  cursor: pointer;
}

/* Names inline + add/remove buttons (Nộp video) */
.names-inline-container {
  display: flex;
  flex-wrap: wrap;
  gap: 10px;
  align-items: center;
}

.name-input-row {
  flex: 1 1 200px;
}

.name-input-row input {
  padding: 10px 14px;
  font-size: 14px;
}

.name-action-buttons {
  display: flex;
  gap: 8px;
}

.btn-circle {
  width: 38px;
  height: 38px;
  border-radius: 50%;
  border: 1px solid rgba(14, 94, 111, 0.2);
  background: rgba(14, 94, 111, 0.05);
  color: var(--primary);
  font-size: 20px;
  font-weight: 700;
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: var(--transition);
}

.btn-circle:hover:not(:disabled) {
  background: var(--primary);
  color: #ffffff;
  box-shadow: var(--shadow-sm);
}

.btn-circle:disabled {
  opacity: 0.45;
  cursor: not-allowed;
}

.sub-btn {
  font-size: 22px;
  line-height: 0;
}

/* Radio circle layout (Nộp video shifts) */
.ca-group {
  display: flex;
  flex-wrap: wrap;
  gap: 20px;
  align-items: center;
  padding: 10px 0;
}

.ca-item {
  display: flex;
  align-items: center;
  gap: 8px;
  cursor: pointer;
  font-weight: 700;
  color: var(--text);
  user-select: none;
  margin: 0;
}

.ca-item input[type="radio"] {
  accent-color: var(--primary);
  width: 18px;
  height: 18px;
  cursor: pointer;
}

/* File Upload Zone styling */
.file-upload-box {
  padding: 16px;
  border: 2px dashed rgba(14, 94, 111, 0.25);
  border-radius: 18px;
  background: rgba(244, 251, 250, 0.6);
  transition: var(--transition);
}

.file-upload-box:hover {
  border-color: var(--accent);
  background: rgba(47, 184, 172, 0.03);
}

.file-upload-dropzone {
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  padding: 20px;
  cursor: pointer;
}

.upload-icon {
  font-size: 32px;
  margin-bottom: 8px;
  transition: transform 0.2s ease;
}

.file-upload-dropzone:hover .upload-icon {
  transform: scale(1.15);
}

.upload-text {
  font-size: 13.5px;
  font-weight: 700;
  color: var(--primary);
}

/* File preview list */
.file-preview-list {
  margin-top: 12px;
  display: flex;
  flex-direction: column;
  gap: 8px;
}

.file-preview-item {
  display: flex;
  align-items: center;
  justify-content: space-between;
  gap: 12px;
  background: #ffffff;
  border: 1px solid var(--border);
  padding: 10px 14px;
  border-radius: 12px;
  box-shadow: var(--shadow-sm);
  animation: slideIn 0.2s ease;
}

.no-files-hint {
  font-size: 12.5px;
  color: #a3b8b5;
  text-align: center;
  padding: 6px 0;
}

.file-info-col {
  display: flex;
  align-items: center;
  gap: 8px;
  overflow: hidden;
  flex: 1;
}

.file-num {
  font-size: 13px;
  font-weight: 700;
  color: var(--accent);
}

.file-details {
  display: flex;
  flex-direction: column;
  overflow: hidden;
  flex: 1;
}

.file-name {
  font-size: 13.5px;
  font-weight: 700;
  white-space: nowrap;
  text-overflow: ellipsis;
  overflow: hidden;
  color: var(--text);
}

.file-size {
  font-size: 11px;
  color: var(--muted);
  margin-top: 1px;
}

.drive-preview-name {
  font-size: 11.5px;
  color: var(--muted);
  margin-top: 2px;
  overflow-wrap: anywhere;
}

.drive-preview-name b {
  color: var(--primary);
}

.btn-remove-file {
  border: 1px solid rgba(211, 47, 47, 0.2);
  background: var(--danger-bg);
  color: var(--danger);
  padding: 6px 12px;
  border-radius: 8px;
  font-size: 12px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
}

.btn-remove-file:hover {
  background: var(--danger);
  color: #ffffff;
  border-color: var(--danger);
}

/* Premium Buttons */
button.btn-primary {
  display: block;
  width: 100%;
  border: none;
  background: linear-gradient(135deg, var(--accent) 0%, var(--primary) 100%);
  color: #ffffff;
  padding: 15px 24px;
  border-radius: 16px;
  font-size: 15px;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 10px 24px rgba(14, 94, 111, 0.2);
  margin-top: 28px;
  transition: var(--transition);
}

button.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 14px 30px rgba(14, 94, 111, 0.28);
  filter: brightness(1.04);
}

button.btn-primary:active {
  transform: translateY(1px);
  filter: brightness(0.96);
}

/* Modal Overlay styling */
.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(11, 43, 51, 0.45);
  backdrop-filter: blur(8px);
  -webkit-backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 9999;
  padding: 16px;
}

.modal-box {
  background: #ffffff;
  border-radius: 24px;
  width: min(780px, 95vw);
  max-height: calc(100vh - 40px);
  box-shadow: var(--shadow-lg);
  border: 1px solid var(--border);
  overflow: hidden;
  display: flex;
  flex-direction: column;
  animation: modalScale 0.25s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.modal-header {
  padding: 20px 24px;
  background: linear-gradient(180deg, rgba(47, 184, 172, 0.08) 0%, rgba(14, 94, 111, 0.03) 100%);
  border-bottom: 1px solid var(--border);
  flex: 0 0 auto;
}

.modal-title {
  font-family: 'Montserrat', sans-serif;
  font-size: 18px;
  font-weight: 800;
  color: var(--primary);
}

.modal-subtitle {
  font-size: 12.5px;
  color: var(--muted);
  margin-top: 4px;
}

.modal-body {
  padding: 24px;
  overflow-y: auto;
  flex: 1 1 auto;
  max-height: calc(100vh - 200px);
}

.modal-actions {
  padding: 16px 24px;
  border-top: 1px solid var(--border);
  background: #ffffff;
  display: flex;
  justify-content: flex-end;
  gap: 12px;
  flex: 0 0 auto;
}

/* Confirm Details Grid Layout */
.confirm-grid {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 10px 20px;
  font-size: 14px;
  line-height: 1.45;
}

.confirm-grid .col-full {
  grid-column: 1 / -1;
}

.confirm-grid b {
  color: var(--primary);
}

@media (max-width: 600px) {
  .confirm-grid {
    grid-template-columns: 1fr;
    gap: 8px;
  }
}

.box-text-pre {
  background: rgba(244, 251, 250, 0.8);
  border: 1px solid var(--border);
  padding: 10px 14px;
  border-radius: 12px;
  font-family: inherit;
  font-size: 13.5px;
  color: var(--text);
  white-space: pre-wrap;
  overflow-wrap: anywhere;
  margin-top: 4px;
}

.total-file-badge {
  background: var(--primary-light);
  border: 1px solid rgba(14, 94, 111, 0.2);
  color: var(--primary);
  font-weight: 800;
  padding: 8px 12px;
  border-radius: 10px;
  text-align: center;
}

/* File list on drive view */
.file-drive-preview-list {
  background: #FAFDFC;
  border: 1px solid var(--border);
  border-radius: 12px;
  padding: 10px;
  margin-top: 6px;
  display: flex;
  flex-direction: column;
  gap: 6px;
}

.preview-name-row {
  display: flex;
  align-items: center;
  font-size: 13px;
  gap: 8px;
  flex-wrap: wrap;
}

.preview-name-row .arrow-right {
  color: var(--accent);
  font-weight: bold;
}

.preview-name-row .drive-name {
  color: var(--primary);
}

/* Progress Layout on Upload */
.progress-container {
  display: flex;
  flex-direction: column;
  gap: 12px;
}

.progress-header-row {
  display: flex;
  justify-content: space-between;
  align-items: center;
}

.progress-status-title {
  font-weight: 800;
  color: var(--primary);
  font-size: 15px;
}

.progress-badge {
  background: var(--accent-glow);
  color: var(--primary);
  font-weight: 800;
  font-size: 12.5px;
  padding: 4px 10px;
  border-radius: 20px;
}

.progress-bar-bg {
  height: 12px;
  background: rgba(47, 184, 172, 0.12);
  border-radius: 20px;
  overflow: hidden;
  border: 1px solid rgba(47, 184, 172, 0.2);
}

.progress-bar-fill {
  height: 100%;
  width: 0%;
  background: linear-gradient(90deg, var(--accent) 0%, var(--primary) 100%);
  border-radius: 20px;
  transition: width 0.15s ease;
}

.progress-meta-row {
  display: flex;
  flex-wrap: wrap;
  gap: 10px 20px;
  font-size: 12.5px;
  color: var(--muted);
  border-bottom: 1px solid var(--border);
  padding-bottom: 12px;
}

.progress-meta-row b {
  color: var(--text);
}

/* Logging Console styling */
.log-output-box {
  background: #0B2B33;
  color: #E8F5F3;
  border-radius: 14px;
  padding: 14px;
  font-family: ui-monospace, SFMono-Regular, SF Mono, Menlo, Monaco, Consolas, monospace;
  font-size: 12px;
  line-height: 1.5;
  height: 200px;
  overflow-y: auto;
  white-space: pre-wrap;
  box-shadow: inset 0 2px 8px rgba(0, 0, 0, 0.35);
  border: 1px solid rgba(14, 94, 111, 0.4);
}

.warning-banner {
  background: var(--danger-bg);
  border: 1px solid var(--danger-border);
  color: #7A1A1A;
  padding: 10px 14px;
  border-radius: 12px;
  font-size: 12.5px;
  text-align: center;
  margin-top: 6px;
}

/* Action controls */
.btn-ghost {
  background: #ffffff;
  color: var(--muted);
  border: 1px solid var(--border);
  padding: 10px 20px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
}

.btn-ghost:hover {
  background: var(--primary-light);
  color: var(--primary);
  border-color: var(--primary);
}

.btn-primary-action {
  border: none;
  background: var(--primary);
  color: #ffffff;
  padding: 10px 20px;
  border-radius: 12px;
  font-size: 14px;
  font-weight: 800;
  cursor: pointer;
  box-shadow: 0 4px 12px rgba(14, 94, 111, 0.15);
  transition: var(--transition);
}

.btn-primary-action:hover {
  filter: brightness(1.05);
  box-shadow: 0 6px 18px rgba(14, 94, 111, 0.25);
  transform: translateY(-1px);
}

.btn-primary-action:disabled {
  opacity: 0.55;
  cursor: not-allowed;
  transform: none;
  box-shadow: none;
}

/* Animations */
@keyframes fadeIn {
  from { opacity: 0; transform: translateY(6px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideIn {
  from { opacity: 0; transform: translateX(-10px); }
  to { opacity: 1; transform: translateX(0); }
}

@keyframes modalScale {
  from { opacity: 0; transform: scale(0.95); }
  to { opacity: 1; transform: scale(1); }
}

.ok {
  background: var(--ok-bg);
  border: 1px solid rgba(46, 125, 50, 0.2);
  color: var(--ok);
  padding: 12px;
  border-radius: 14px;
  font-size: 14px;
  font-weight: 700;
  margin-bottom: 12px;
}

.ok a {
  color: var(--primary);
  text-decoration: underline;
}

.ok a:hover {
  color: var(--accent);
}

/* In-App Browser Warning Banner styling */
.warning-banner-top {
  background: rgba(255, 235, 235, 0.95);
  backdrop-filter: blur(12px);
  -webkit-backdrop-filter: blur(12px);
  border: 1px solid rgba(211, 47, 47, 0.25);
  color: #7A1A1A;
  padding: 14px 40px 14px 20px;
  border-radius: 16px;
  font-size: 13.5px;
  line-height: 1.5;
  margin-bottom: 20px;
  box-shadow: 0 8px 32px rgba(211, 47, 47, 0.08);
  animation: fadeIn 0.4s ease;
  position: relative;
}

.warning-banner-top b {
  color: var(--danger);
}

.warning-banner-top .close-banner-btn {
  position: absolute;
  right: 14px;
  top: 50%;
  transform: translateY(-50%);
  border: none;
  background: transparent;
  font-size: 22px;
  color: #7A1A1A;
  cursor: pointer;
  opacity: 0.6;
  transition: opacity 0.2s ease;
  line-height: 1;
}

.warning-banner-top .close-banner-btn:hover {
  opacity: 1;
}

/* Full-screen blocker overlay for In-App Browsers */
.in-app-blocker-overlay {
  position: fixed;
  inset: 0;
  background: linear-gradient(135deg, rgba(11, 43, 51, 0.92) 0%, rgba(14, 94, 111, 0.96) 100%);
  backdrop-filter: blur(20px);
  -webkit-backdrop-filter: blur(20px);
  z-index: 100000;
  display: flex;
  align-items: center;
  justify-content: center;
  padding: 24px;
}

.blocker-box {
  background: rgba(255, 255, 255, 0.95);
  border-radius: 28px;
  width: min(480px, 90vw);
  padding: 32px 24px;
  text-align: center;
  box-shadow: 0 20px 50px rgba(0, 0, 0, 0.3);
  border: 1px solid rgba(255, 255, 255, 0.25);
  animation: modalScale 0.35s cubic-bezier(0.34, 1.56, 0.64, 1);
}

.blocker-icon {
  font-size: 54px;
  margin-bottom: 16px;
  animation: pulse 1.5s infinite;
}

.blocker-box h2 {
  font-family: 'Montserrat', sans-serif;
  color: #D32F2F;
  font-size: 20px;
  font-weight: 800;
  margin-bottom: 12px;
}

.blocker-desc {
  font-size: 14px;
  color: var(--text);
  line-height: 1.5;
  margin-bottom: 24px;
}

.blocker-instruction {
  background: var(--primary-light);
  border: 1px solid var(--border);
  border-radius: 18px;
  padding: 18px;
  text-align: left;
  margin-bottom: 20px;
}

.blocker-instruction h3 {
  font-size: 13.5px;
  color: var(--primary);
  font-weight: 800;
  margin-bottom: 10px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

.blocker-instruction ol {
  padding-left: 20px;
  font-size: 13.5px;
  color: var(--text);
  line-height: 1.6;
}

.blocker-instruction li {
  margin-bottom: 8px;
}

.blocker-instruction li:last-child {
  margin-bottom: 0;
}

.blocker-footer {
  font-size: 12.5px;
  color: var(--muted);
  font-weight: 500;
}

@keyframes pulse {
  0% { transform: scale(1); }
  50% { transform: scale(1.1); }
  100% { transform: scale(1); }
}

/* Music Control Panel in Progress Modal */
.music-control-panel {
  display: flex;
  align-items: center;
  justify-content: space-between;
  background: var(--primary-light);
  border: 1px solid var(--border);
  padding: 10px 16px;
  border-radius: 14px;
  margin-bottom: 16px;
  gap: 12px;
}

.music-info-row {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 13px;
  color: var(--primary);
}

.music-disk-icon {
  font-size: 18px;
  animation: spin-cd 3s linear infinite;
  display: inline-block;
}

.btn-music-toggle {
  background: #ffffff;
  border: 1px solid var(--border);
  color: var(--primary);
  padding: 6px 12px;
  border-radius: 10px;
  font-size: 12.5px;
  font-weight: 700;
  cursor: pointer;
  transition: var(--transition);
}

.btn-music-toggle:hover {
  background: var(--primary);
  color: #ffffff;
  border-color: var(--primary);
}

.btn-music-toggle.muted {
  background: var(--accent-glow);
  color: var(--primary);
}

@keyframes spin-cd {
  from { transform: rotate(0deg); }
  to { transform: rotate(360deg); }
}

/* ==========================================================================
   CLASS INFOMATION CONTAINER LAYOUT (DESKTOP & MOBILE RESPONSIVE OPTIMIZATION)
   ========================================================================== */
.classes-layout-container {
  display: grid;
  grid-template-columns: 1fr;
  gap: 20px;
  margin-top: 15px;
  width: 100%;
}

.class-info-block {
  background: rgba(47, 184, 172, 0.02);
  border: 1px solid rgba(47, 184, 172, 0.12);
  border-radius: 20px;
  padding: 20px;
  transition: all 0.3s ease;
  box-shadow: 0 4px 12px rgba(14, 94, 111, 0.02);
  width: 100%;
  box-sizing: border-box;
}

.class-info-block:hover {
  background: rgba(47, 184, 172, 0.03);
  border-color: rgba(47, 184, 172, 0.2);
  box-shadow: 0 6px 16px rgba(14, 94, 111, 0.04);
}

.class-section-header {
  font-family: 'Montserrat', sans-serif;
  font-weight: 800;
  color: var(--primary);
  font-size: 15px;
  border-bottom: 2px solid rgba(14, 94, 111, 0.1);
  padding-bottom: 8px;
  margin-bottom: 16px;
  letter-spacing: 0.5px;
  text-transform: uppercase;
}

/* Hiển thị song song 2 cột trên màn hình Desktop (từ 769px trở lên) */
@media (min-width: 769px) {
  .classes-layout-container.dual-classes {
    grid-template-columns: 1fr 1fr;
  }
}

/* Tối ưu hóa padding của form và container trên màn hình di động nhỏ */
@media (max-width: 600px) {
  .wrap {
    padding: 12px 8px;
  }
  .card {
    padding: 16px 12px;
    border-radius: 18px;
  }
  .header {
    flex-direction: column;
    align-items: flex-start;
    gap: 12px;
  }
  h1 {
    font-size: 19px;
  }
  .form-section-title {
    font-size: 16px;
    margin-bottom: 14px;
  }
  .class-info-block {
    padding: 12px 10px;
    border-radius: 14px;
  }
}

/* Dynamic upload blocks per class style improvements */
#dynamicUploadsContainer {
  margin-top: 20px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.class-upload-block {
  background: rgba(255, 255, 255, 0.45);
  border: 1px solid rgba(14, 94, 111, 0.15);
  border-radius: 20px;
  padding: 24px;
  backdrop-filter: blur(6px);
  -webkit-backdrop-filter: blur(6px);
  box-shadow: 0 8px 32px rgba(14, 94, 111, 0.03);
  transition: all 0.3s ease;
}

.class-upload-block:hover {
  border-color: var(--accent);
  box-shadow: 0 12px 40px rgba(14, 94, 111, 0.06);
  transform: translateY(-2px);
}

.class-upload-header {
  font-family: 'Montserrat', sans-serif;
  font-size: 16px;
  font-weight: 800;
  color: var(--primary);
  margin-bottom: 18px;
  border-bottom: 2px solid rgba(47, 184, 172, 0.15);
  padding-bottom: 8px;
  text-transform: uppercase;
  letter-spacing: 0.5px;
}

/* Adjust mobile layout for class upload block */
@media (max-width: 600px) {
  .class-upload-block {
    padding: 16px 12px;
    border-radius: 16px;
  }
  .class-upload-header {
    font-size: 14px;
    margin-bottom: 12px;
  }
}