@import url('https://fonts.googleapis.com/css2?family=Inter:wght@300;400;500;600;700;800&display=swap');

:root {
  --bg-primary: #0a0e1a;
  --bg-secondary: #111827;
  --bg-card: rgba(17, 24, 39, 0.7);
  --bg-glass: rgba(255, 255, 255, 0.04);
  --border-glass: rgba(255, 255, 255, 0.08);
  --text-primary: #f1f5f9;
  --text-secondary: #94a3b8;
  --text-muted: #64748b;
  --accent: #6366f1;
  --accent-light: #818cf8;
  --accent-glow: rgba(99, 102, 241, 0.3);
  --success: #10b981;
  --success-glow: rgba(16, 185, 129, 0.3);
  --error: #ef4444;
  --error-glow: rgba(239, 68, 68, 0.2);
  --warning: #f59e0b;
  --gradient-1: linear-gradient(135deg, #6366f1 0%, #8b5cf6 50%, #a78bfa 100%);
  --gradient-2: linear-gradient(135deg, #0ea5e9 0%, #6366f1 100%);
  --radius: 12px;
  --radius-lg: 16px;
  --shadow: 0 4px 24px rgba(0, 0, 0, 0.3);
  --transition: all 0.3s cubic-bezier(0.4, 0, 0.2, 1);

  /* Concentration Colors */
  --de-color: #0ea5e9;
  --de-glow: rgba(14, 165, 233, 0.25);
  --de-gradient: linear-gradient(135deg, #0ea5e9 0%, #38bdf8 100%);

  --ai-color: #a855f7;
  --ai-glow: rgba(168, 85, 247, 0.25);
  --ai-gradient: linear-gradient(135deg, #a855f7 0%, #c084fc 100%);

  --bi-color: #f97316;
  --bi-glow: rgba(249, 115, 22, 0.25);
  --bi-gradient: linear-gradient(135deg, #f97316 0%, #fb923c 100%);
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { scroll-behavior: smooth; }

body {
  font-family: 'Inter', -apple-system, sans-serif;
  background: var(--bg-primary);
  color: var(--text-primary);
  min-height: 100vh;
  line-height: 1.6;
  overflow-x: hidden;
}

body::before {
  content: '';
  position: fixed;
  top: -50%; left: -50%;
  width: 200%; height: 200%;
  background:
    radial-gradient(circle at 30% 20%, rgba(99, 102, 241, 0.08) 0%, transparent 50%),
    radial-gradient(circle at 70% 80%, rgba(139, 92, 246, 0.06) 0%, transparent 50%),
    radial-gradient(circle at 50% 50%, rgba(14, 165, 233, 0.04) 0%, transparent 60%);
  z-index: -1;
  animation: bgShift 20s ease-in-out infinite alternate;
}

@keyframes bgShift {
  0% { transform: translate(0, 0) rotate(0deg); }
  100% { transform: translate(-2%, -2%) rotate(3deg); }
}

.container {
  max-width: 900px;
  margin: 0 auto;
  padding: 24px 16px 60px;
}

/* ============ Header ============ */
.app-header {
  text-align: center;
  padding: 40px 0 32px;
}

.app-header .logo {
  width: 72px; height: 72px;
  background: var(--gradient-1);
  border-radius: 20px;
  display: inline-flex;
  align-items: center; justify-content: center;
  font-size: 32px;
  margin-bottom: 16px;
  box-shadow: 0 8px 32px var(--accent-glow);
  animation: float 3s ease-in-out infinite;
}

@keyframes float {
  0%, 100% { transform: translateY(0); }
  50% { transform: translateY(-6px); }
}

.app-header h1 {
  font-size: 1.75rem;
  font-weight: 800;
  background: var(--gradient-1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
  margin-bottom: 6px;
}

.app-header p {
  color: var(--text-secondary);
  font-size: 0.9rem;
}

/* ============ Card ============ */
.card {
  background: var(--bg-card);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 32px 28px;
  backdrop-filter: blur(16px);
  -webkit-backdrop-filter: blur(16px);
  box-shadow: var(--shadow);
  animation: cardIn 0.4s ease-out;
}

@keyframes cardIn {
  from { opacity: 0; transform: translateY(16px); }
  to { opacity: 1; transform: translateY(0); }
}

.card-title {
  font-size: 1.25rem;
  font-weight: 700;
  margin-bottom: 4px;
  display: flex;
  align-items: center;
  gap: 10px;
}

.card-title .icon { font-size: 1.3rem; }

.card-subtitle {
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-bottom: 24px;
}

/* ============ Form Elements ============ */
.form-group {
  margin-bottom: 20px;
}

.form-group label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

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

input[type="text"],
input[type="number"],
select,
textarea {
  width: 100%;
  padding: 12px 16px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  color: var(--text-primary);
  font-family: 'Inter', sans-serif;
  font-size: 0.9rem;
  transition: var(--transition);
  outline: none;
}

input:focus, select:focus, textarea:focus {
  border-color: var(--accent);
  box-shadow: 0 0 0 3px var(--accent-glow);
  background: rgba(99, 102, 241, 0.05);
}

input::placeholder, textarea::placeholder {
  color: var(--text-muted);
}

textarea {
  min-height: 80px;
  resize: vertical;
}

select {
  cursor: pointer;
  appearance: none;
  background-image: url("data:image/svg+xml,%3Csvg xmlns='http://www.w3.org/2000/svg' width='12' height='12' fill='%2394a3b8' viewBox='0 0 16 16'%3E%3Cpath d='M8 11L3 6h10l-5 5z'/%3E%3C/svg%3E");
  background-repeat: no-repeat;
  background-position: right 14px center;
  padding-right: 36px;
}

select option {
  background: var(--bg-secondary);
  color: var(--text-primary);
}

/* ============ Buttons ============ */
.btn-group {
  display: flex;
  gap: 12px;
  margin-top: 28px;
}

.btn {
  flex: 1;
  padding: 14px 24px;
  border: none;
  border-radius: var(--radius);
  font-family: 'Inter', sans-serif;
  font-size: 0.9rem;
  font-weight: 600;
  cursor: pointer;
  transition: var(--transition);
  display: flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
}

.btn-primary {
  background: var(--gradient-1);
  color: #fff;
  box-shadow: 0 4px 16px var(--accent-glow);
}

.btn-primary:hover {
  transform: translateY(-2px);
  box-shadow: 0 8px 24px var(--accent-glow);
}

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

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

.btn-secondary:hover {
  border-color: var(--accent);
  color: var(--text-primary);
}

.btn:disabled {
  opacity: 0.5;
  cursor: not-allowed;
  transform: none !important;
}

/* ============ Alert Messages ============ */
.alert {
  padding: 14px 18px;
  border-radius: var(--radius);
  font-size: 0.85rem;
  font-weight: 500;
  display: none;
  align-items: center;
  gap: 10px;
  margin-top: 16px;
  animation: shakeIn 0.4s ease;
}

@keyframes shakeIn {
  0% { transform: translateX(-8px); opacity: 0; }
  50% { transform: translateX(4px); }
  100% { transform: translateX(0); opacity: 1; }
}

.alert.show { display: flex; }

.alert-error {
  background: var(--error-glow);
  border: 1px solid rgba(239, 68, 68, 0.3);
  color: #fca5a5;
}

.alert-success {
  background: var(--success-glow);
  border: 1px solid rgba(16, 185, 129, 0.3);
  color: #6ee7b7;
}

.alert-warning {
  background: rgba(245, 158, 11, 0.15);
  border: 1px solid rgba(245, 158, 11, 0.3);
  color: #fcd34d;
}

/* ============ Loading ============ */
.loading-state {
  text-align: center;
  padding: 60px 20px;
}

.spinner {
  width: 24px; height: 24px;
  border: 2.5px solid rgba(255,255,255,0.2);
  border-top-color: var(--accent-light);
  border-radius: 50%;
  animation: spin 0.7s linear infinite;
  display: inline-block;
  margin-bottom: 12px;
}

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

.loading-state p {
  color: var(--text-muted);
  font-size: 0.85rem;
}

/* ============ Concentration Cards Grid ============ */
.concentration-section {
  margin-top: 8px;
}

.concentration-section .section-title {
  font-size: 1.1rem;
  font-weight: 700;
  margin-bottom: 6px;
  display: flex;
  align-items: center;
  gap: 8px;
}

.concentration-section .section-subtitle {
  color: var(--text-muted);
  font-size: 0.82rem;
  margin-bottom: 20px;
}

.conc-grid {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.conc-card {
  background: var(--bg-card);
  border: 2px solid var(--border-glass);
  border-radius: var(--radius-lg);
  padding: 24px;
  cursor: pointer;
  transition: var(--transition);
  position: relative;
  overflow: hidden;
}

.conc-card::before {
  content: '';
  position: absolute;
  top: 0; left: 0;
  width: 100%; height: 4px;
  opacity: 0.6;
  transition: opacity 0.3s;
}

.conc-card:hover {
  transform: translateY(-3px);
  box-shadow: 0 8px 32px rgba(0,0,0,0.3);
}

.conc-card.selected {
  transform: translateY(-3px);
}

.conc-card.selected::before {
  opacity: 1;
}

/* DE Card */
.conc-card.de::before { background: var(--de-gradient); }
.conc-card.de:hover, .conc-card.de.selected {
  border-color: var(--de-color);
  box-shadow: 0 8px 32px var(--de-glow);
}

/* AI Card */
.conc-card.ai::before { background: var(--ai-gradient); }
.conc-card.ai:hover, .conc-card.ai.selected {
  border-color: var(--ai-color);
  box-shadow: 0 8px 32px var(--ai-glow);
}

/* BI Card */
.conc-card.bi::before { background: var(--bi-gradient); }
.conc-card.bi:hover, .conc-card.bi.selected {
  border-color: var(--bi-color);
  box-shadow: 0 8px 32px var(--bi-glow);
}

.conc-card-header {
  display: flex;
  align-items: flex-start;
  justify-content: space-between;
  gap: 12px;
  margin-bottom: 16px;
}

.conc-card-info {
  flex: 1;
}

.conc-card-badge {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 4px 10px;
  border-radius: 20px;
  font-size: 0.7rem;
  font-weight: 700;
  letter-spacing: 0.5px;
  text-transform: uppercase;
  white-space: nowrap;
}

.conc-card.de .conc-card-badge {
  background: rgba(14, 165, 233, 0.15);
  color: var(--de-color);
  border: 1px solid rgba(14, 165, 233, 0.3);
}

.conc-card.ai .conc-card-badge {
  background: rgba(168, 85, 247, 0.15);
  color: var(--ai-color);
  border: 1px solid rgba(168, 85, 247, 0.3);
}

.conc-card.bi .conc-card-badge {
  background: rgba(249, 115, 22, 0.15);
  color: var(--bi-color);
  border: 1px solid rgba(249, 115, 22, 0.3);
}

.conc-check {
  width: 26px; height: 26px;
  border-radius: 50%;
  border: 2px solid var(--border-glass);
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 14px;
  transition: var(--transition);
  flex-shrink: 0;
  margin-top: 2px;
  background: var(--bg-glass);
}

.conc-card.selected .conc-check {
  border-color: transparent;
  color: #fff;
  font-size: 13px;
}

.conc-card.de.selected .conc-check { background: var(--de-gradient); box-shadow: 0 0 12px var(--de-glow); }
.conc-card.ai.selected .conc-check { background: var(--ai-gradient); box-shadow: 0 0 12px var(--ai-glow); }
.conc-card.bi.selected .conc-check { background: var(--bi-gradient); box-shadow: 0 0 12px var(--bi-glow); }

.conc-card-name {
  font-size: 1.05rem;
  font-weight: 700;
  margin-bottom: 4px;
}

.conc-card-desc {
  color: var(--text-muted);
  font-size: 0.78rem;
  line-height: 1.5;
}

/* Courses List */
.courses-list {
  display: grid;
  grid-template-columns: 1fr 1fr;
  gap: 8px;
}

.course-item {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 12px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: 10px;
  transition: var(--transition);
}

.conc-card:hover .course-item,
.conc-card.selected .course-item {
  background: rgba(255, 255, 255, 0.06);
}

.course-num {
  width: 24px; height: 24px;
  border-radius: 6px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 0.7rem;
  font-weight: 700;
  flex-shrink: 0;
}

.conc-card.de .course-num {
  background: rgba(14, 165, 233, 0.15);
  color: var(--de-color);
}

.conc-card.ai .course-num {
  background: rgba(168, 85, 247, 0.15);
  color: var(--ai-color);
}

.conc-card.bi .course-num {
  background: rgba(249, 115, 22, 0.15);
  color: var(--bi-color);
}

.course-info {
  flex: 1;
  min-width: 0;
}

.course-name {
  font-size: 0.78rem;
  font-weight: 600;
  color: var(--text-primary);
  line-height: 1.3;
}

.course-sks {
  font-size: 0.68rem;
  color: var(--text-muted);
  font-weight: 500;
}

/* Mandatory Course Bar */
.mandatory-bar {
  margin-top: 16px;
  padding: 14px 18px;
  background: rgba(99, 102, 241, 0.08);
  border: 1px solid rgba(99, 102, 241, 0.2);
  border-radius: var(--radius);
  display: flex;
  align-items: center;
  gap: 10px;
  font-size: 0.82rem;
}

.mandatory-bar .mandatory-icon {
  font-size: 1.1rem;
}

.mandatory-bar .mandatory-label {
  color: var(--text-secondary);
  font-weight: 500;
}

.mandatory-bar .mandatory-name {
  color: var(--accent-light);
  font-weight: 600;
}

.mandatory-bar .mandatory-sks {
  margin-left: auto;
  color: var(--text-muted);
  font-size: 0.75rem;
  font-weight: 600;
  background: rgba(99, 102, 241, 0.15);
  padding: 3px 10px;
  border-radius: 20px;
}

/* Total SKS Info */
.total-sks-bar {
  margin-top: 12px;
  padding: 12px 18px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 0.82rem;
}

.total-sks-bar span:first-child {
  color: var(--text-secondary);
  font-weight: 500;
}

.total-sks-bar span:last-child {
  font-weight: 700;
  background: var(--gradient-1);
  -webkit-background-clip: text;
  -webkit-text-fill-color: transparent;
  background-clip: text;
}

/* ============ Reason Section ============ */
.reason-section {
  margin-top: 24px;
  padding-top: 24px;
  border-top: 1px solid var(--border-glass);
}

.reason-section label {
  display: block;
  font-size: 0.85rem;
  font-weight: 600;
  color: var(--text-secondary);
  margin-bottom: 8px;
}

/* ============ Success Screen ============ */
.success-screen {
  text-align: center;
  padding: 48px 24px;
}

.success-screen .check-icon {
  width: 80px; height: 80px;
  background: var(--success);
  border-radius: 50%;
  display: inline-flex;
  align-items: center;
  justify-content: center;
  font-size: 36px;
  margin-bottom: 24px;
  box-shadow: 0 8px 32px var(--success-glow);
  animation: popIn 0.5s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes popIn {
  0% { transform: scale(0); }
  100% { transform: scale(1); }
}

.success-screen h2 {
  font-size: 1.5rem;
  margin-bottom: 8px;
}

.success-screen p {
  color: var(--text-secondary);
  font-size: 0.9rem;
  line-height: 1.6;
}

.success-screen .selected-info {
  margin-top: 24px;
  padding: 20px;
  background: var(--bg-glass);
  border: 1px solid var(--border-glass);
  border-radius: var(--radius);
  text-align: left;
}

.success-screen .selected-info .info-row {
  display: flex;
  justify-content: space-between;
  padding: 8px 0;
  font-size: 0.85rem;
}

.success-screen .selected-info .info-row:not(:last-child) {
  border-bottom: 1px solid var(--border-glass);
}

.success-screen .selected-info .info-label {
  color: var(--text-muted);
}

.success-screen .selected-info .info-value {
  font-weight: 600;
  color: var(--accent-light);
}

/* ============ Validation Error ============ */
.field-error {
  color: #fca5a5;
  font-size: 0.78rem;
  margin-top: 8px;
  display: none;
}

.field-error.show { display: block; }

/* ============ Responsive ============ */
@media (max-width: 640px) {
  .container { padding: 16px 12px 48px; }
  .card { padding: 24px 18px; }
  .app-header h1 { font-size: 1.4rem; }
  .courses-list { grid-template-columns: 1fr; }
  .conc-card { padding: 18px; }
  .btn-group { flex-direction: column-reverse; }
  .mandatory-bar { flex-wrap: wrap; }
  .mandatory-bar .mandatory-sks { margin-left: 0; margin-top: 4px; }
}

/* ============ Scrollbar ============ */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border-glass); border-radius: 100px; }
::-webkit-scrollbar-thumb:hover { background: var(--text-muted); }

/* ============ Selection indicator pulse ============ */
@keyframes pulse-border {
  0%, 100% { opacity: 1; }
  50% { opacity: 0.5; }
}

.conc-card.selected {
  animation: selectPop 0.3s ease-out;
}

@keyframes selectPop {
  0% { transform: scale(0.98); }
  50% { transform: scale(1.01); }
  100% { transform: translateY(-3px) scale(1); }
}

/* ============ Student Info Bar ============ */
.student-info-bar {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 14px 18px;
  background: rgba(99, 102, 241, 0.06);
  border: 1px solid rgba(99, 102, 241, 0.15);
  border-radius: var(--radius);
  margin-bottom: 24px;
  animation: cardIn 0.3s ease-out;
}

.student-info-bar .avatar {
  width: 40px; height: 40px;
  background: var(--gradient-1);
  border-radius: 10px;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 18px;
  flex-shrink: 0;
}

.student-info-bar .student-details {
  flex: 1;
}

.student-info-bar .student-name {
  font-size: 0.9rem;
  font-weight: 700;
  color: var(--text-primary);
}

.student-info-bar .student-nim {
  font-size: 0.75rem;
  color: var(--text-muted);
  font-weight: 500;
}