/* =============================================
   schulorganizer.de – Mathe-Tutor Styles v2
   ============================================= */

:root {
  --bg-page:        #f0f4ff;
  --bg-app:         #ffffff;
  --bg-tutor:       #eef2ff;
  --bg-student:     #4f46e5;
  --bg-header:      #1e1b4b;
  --bg-sidebar:     #f8f9ff;
  --accent:         #4f46e5;
  --accent-light:   #818cf8;
  --accent-hover:   #3730a3;
  --accent-soft:    #e0e7ff;
  --success:        #059669;
  --success-bg:     #d1fae5;
  --pending:        #9ca3af;
  --text-dark:      #1e1b4b;
  --text-mid:       #4b5563;
  --text-light:     #9ca3af;
  --text-student:   #ffffff;
  --text-tutor:     #1e1b4b;
  --border:         #e0e7ff;
  --shadow-sm:      0 2px 8px rgba(79,70,229,0.08);
  --shadow-md:      0 4px 20px rgba(79,70,229,0.13);
  --shadow-lg:      0 8px 40px rgba(79,70,229,0.18);
  --radius-bubble:  18px;
  --radius-input:   14px;
  --sidebar-width:  280px;
  --font-main:      'Nunito', sans-serif;
  --font-mono:      'Fira Mono', monospace;
}

*, *::before, *::after { box-sizing: border-box; margin: 0; padding: 0; }
html { font-size: 16px; -webkit-text-size-adjust: 100%; }

body {
  font-family: var(--font-main);
  background: var(--bg-page);
  background-image:
    radial-gradient(circle at 15% 15%, rgba(129,140,248,0.15) 0%, transparent 50%),
    radial-gradient(circle at 85% 85%, rgba(79,70,229,0.10) 0%, transparent 50%);
  min-height: 100dvh;
  display: flex;
  align-items: stretch;
  justify-content: center;
}

/* ── App Shell ───────────────────────────────── */
.app-shell {
  width: 100%;
  max-width: 1100px;
  display: flex;
  flex-direction: column;
  background: var(--bg-app);
  box-shadow: var(--shadow-lg);
  min-height: 100dvh;
}

/* ── Header ──────────────────────────────────── */
.app-header {
  background: var(--bg-header);
  padding: 16px 24px;
  display: flex;
  align-items: center;
  gap: 12px;
  flex-shrink: 0;
  position: sticky;
  top: 0;
  z-index: 100;
}

.header-logo {
  display: flex;
  align-items: center;
  gap: 8px;
  font-size: 1.15rem;
  font-weight: 800;
  color: #fff;
  letter-spacing: -0.02em;
}
.logo-icon { color: var(--accent-light); }
.logo-dot  { color: var(--accent-light); }

.header-subtitle {
  font-size: 0.72rem;
  color: rgba(255,255,255,0.45);
  font-weight: 600;
  letter-spacing: 0.05em;
  text-transform: uppercase;
  flex: 1;
}

.sidebar-toggle {
  display: none;
  background: rgba(255,255,255,0.1);
  border: none;
  border-radius: 8px;
  color: #fff;
  width: 38px;
  height: 38px;
  cursor: pointer;
  align-items: center;
  justify-content: center;
  transition: background 0.2s;
}
.sidebar-toggle:hover { background: rgba(255,255,255,0.2); }

/* ── App Body (Sidebar + Main) ───────────────── */
.app-body {
  display: flex;
  flex: 1;
  overflow: hidden;
  height: calc(100dvh - 57px);
}

/* ── Sidebar ─────────────────────────────────── */
.sidebar {
  width: var(--sidebar-width);
  flex-shrink: 0;
  background: var(--bg-sidebar);
  border-right: 1px solid var(--border);
  display: flex;
  flex-direction: column;
  overflow-y: auto;
  transition: transform 0.3s ease;
}

.sidebar::-webkit-scrollbar { width: 3px; }
.sidebar::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

.sidebar-header {
  padding: 16px 16px 12px;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.sidebar-title {
  font-size: 0.8rem;
  font-weight: 800;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--accent);
}

.sidebar-section {
  padding: 14px 16px 8px;
  border-bottom: 1px solid var(--border);
}

.sidebar-section-label {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.07em;
  color: var(--text-light);
  margin-bottom: 8px;
}

.sidebar-topic {
  font-size: 0.88rem;
  font-weight: 700;
  color: var(--text-dark);
  background: var(--accent-soft);
  border-radius: 8px;
  padding: 8px 12px;
  line-height: 1.4;
}

/* ── Schritte-Liste ──────────────────────────── */
.steps-list {
  list-style: none;
  display: flex;
  flex-direction: column;
  gap: 6px;
  padding: 0;
}

.step-item {
  display: flex;
  align-items: flex-start;
  gap: 10px;
  padding: 8px 10px;
  border-radius: 10px;
  border: 1px solid var(--border);
  background: #fff;
  transition: border-color 0.2s, background 0.2s;
  animation: fadeInStep 0.3s ease-out;
}

@keyframes fadeInStep {
  from { opacity: 0; transform: translateX(-8px); }
  to   { opacity: 1; transform: translateX(0); }
}

.step-item.done {
  background: var(--success-bg);
  border-color: #6ee7b7;
}

.step-item.active {
  border-color: var(--accent);
  background: var(--accent-soft);
}

.step-number {
  flex-shrink: 0;
  width: 22px;
  height: 22px;
  border-radius: 50%;
  background: var(--border);
  color: var(--text-mid);
  font-size: 0.7rem;
  font-weight: 800;
  display: flex;
  align-items: center;
  justify-content: center;
  margin-top: 1px;
}

.step-item.done   .step-number { background: var(--success); color: #fff; }
.step-item.active .step-number { background: var(--accent);  color: #fff; }

.step-content {
  flex: 1;
  min-width: 0;
}

.step-text {
  font-size: 0.82rem;
  color: var(--text-dark);
  line-height: 1.4;
  font-weight: 600;
}

.step-item.done .step-text { color: var(--success); }

/* Erklärung-Button */
.step-explain-btn {
  flex-shrink: 0;
  background: none;
  border: 1px solid var(--border);
  border-radius: 6px;
  color: var(--accent);
  font-size: 0.68rem;
  font-weight: 700;
  padding: 2px 7px;
  cursor: pointer;
  transition: background 0.15s, border-color 0.15s;
  white-space: nowrap;
  margin-top: 2px;
  font-family: var(--font-main);
}
.step-explain-btn:hover {
  background: var(--accent-soft);
  border-color: var(--accent);
}

/* ── Leer-Zustand Sidebar ────────────────────── */
.sidebar-empty {
  padding: 32px 20px;
  text-align: center;
  color: var(--text-light);
  flex: 1;
  display: flex;
  flex-direction: column;
  align-items: center;
  justify-content: center;
  gap: 10px;
}
.sidebar-empty-icon { font-size: 2.2rem; }
.sidebar-empty p    { font-size: 0.82rem; line-height: 1.6; }

/* ── Hauptbereich ────────────────────────────── */
.main-area {
  flex: 1;
  display: flex;
  flex-direction: column;
  overflow: hidden;
  min-width: 0;
}

/* ── Aufgaben-Eingabe ────────────────────────── */
.task-input-area {
  padding: 16px 20px 14px;
  background: #f8f9ff;
  border-bottom: 1px solid var(--border);
  flex-shrink: 0;
}

.task-label {
  display: block;
  font-size: 0.72rem;
  font-weight: 700;
  color: var(--accent);
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 7px;
}

.task-input-row {
  display: flex;
  gap: 10px;
  align-items: center;
}

.task-input {
  flex: 1;
  padding: 11px 15px;
  border: 2px solid var(--border);
  border-radius: var(--radius-input);
  font-family: var(--font-mono);
  font-size: 0.92rem;
  color: var(--text-dark);
  background: #fff;
  outline: none;
  transition: border-color 0.2s, box-shadow 0.2s;
}
.task-input::placeholder { color: var(--text-light); font-family: var(--font-main); font-size: 0.85rem; }
.task-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(79,70,229,0.12); }

.start-btn {
  flex-shrink: 0;
  width: 44px; height: 44px;
  border: none; border-radius: 12px;
  background: var(--accent); color: #fff;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  box-shadow: var(--shadow-sm);
}
.start-btn:hover { background: var(--accent-hover); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.start-btn:active { transform: translateY(0); }

/* ── Chat-Container ──────────────────────────── */
.chat-container {
  flex: 1;
  padding: 18px 16px;
  overflow-y: auto;
  display: flex;
  flex-direction: column;
  gap: 12px;
  scroll-behavior: smooth;
}
.chat-container::-webkit-scrollbar { width: 4px; }
.chat-container::-webkit-scrollbar-thumb { background: var(--border); border-radius: 4px; }

.chat-welcome {
  margin: auto;
  text-align: center;
  padding: 32px 20px;
  opacity: 0.65;
}
.welcome-icon  { font-size: 2.8rem; margin-bottom: 14px; }
.welcome-text  { color: var(--text-mid); font-size: 0.92rem; line-height: 1.7; }

/* ── Nachrichten ─────────────────────────────── */
.message-row {
  display: flex;
  flex-direction: column;
  max-width: 82%;
  animation: slideIn 0.22s ease-out;
}
@keyframes slideIn {
  from { opacity: 0; transform: translateY(8px); }
  to   { opacity: 1; transform: translateY(0); }
}

.message-row.tutor   { align-self: flex-start; align-items: flex-start; }
.message-row.student { align-self: flex-end;   align-items: flex-end; }

.message-sender {
  font-size: 0.68rem;
  font-weight: 700;
  text-transform: uppercase;
  letter-spacing: 0.06em;
  margin-bottom: 3px;
  padding: 0 3px;
}
.message-row.tutor   .message-sender { color: var(--accent); }
.message-row.student .message-sender { color: var(--text-mid); }

.message-bubble {
  padding: 11px 15px;
  border-radius: var(--radius-bubble);
  line-height: 1.65;
  font-size: 0.93rem;
  box-shadow: var(--shadow-sm);
  word-break: break-word;
}
.message-row.tutor .message-bubble {
  background: var(--bg-tutor);
  color: var(--text-tutor);
  border-bottom-left-radius: 4px;
  border: 1px solid var(--border);
}
.message-row.student .message-bubble {
  background: var(--bg-student);
  color: var(--text-student);
  border-bottom-right-radius: 4px;
}

.task-chip {
  align-self: center;
  background: #fff;
  border: 2px solid var(--accent);
  border-radius: 50px;
  padding: 5px 16px;
  font-family: var(--font-mono);
  font-size: 0.85rem;
  color: var(--accent);
  font-weight: 600;
  box-shadow: var(--shadow-sm);
  max-width: 100%;
  text-align: center;
  word-break: break-all;
}

/* ── Tipp-Indikator ──────────────────────────── */
.typing-indicator {
  display: flex;
  align-items: center;
  gap: 10px;
  padding: 10px 14px;
  background: var(--bg-tutor);
  border: 1px solid var(--border);
  border-radius: var(--radius-bubble);
  border-bottom-left-radius: 4px;
  align-self: flex-start;
  box-shadow: var(--shadow-sm);
  animation: slideIn 0.2s ease-out;
}
.typing-indicator span { font-size: 0.78rem; color: var(--text-mid); font-weight: 600; }

.typing-dots { display: flex; gap: 4px; }
.typing-dots i {
  width: 6px; height: 6px;
  border-radius: 50%;
  background: var(--accent-light);
  display: block;
  animation: bounce 1.2s infinite;
}
.typing-dots i:nth-child(2) { animation-delay: 0.2s; }
.typing-dots i:nth-child(3) { animation-delay: 0.4s; }
@keyframes bounce {
  0%,60%,100% { transform: translateY(0); }
  30%         { transform: translateY(-5px); }
}

/* ── Antwort-Bereich ─────────────────────────── */
.reply-area {
  padding: 10px 16px 14px;
  border-top: 1px solid var(--border);
  background: #fff;
  flex-shrink: 0;
}
.reply-input-row { display: flex; gap: 10px; align-items: flex-end; }

.reply-input {
  flex: 1;
  padding: 11px 15px;
  border: 2px solid var(--border);
  border-radius: var(--radius-input);
  font-family: var(--font-main);
  font-size: 0.92rem;
  color: var(--text-dark);
  background: #f8f9ff;
  outline: none;
  resize: none;
  min-height: 44px;
  max-height: 110px;
  line-height: 1.5;
  transition: border-color 0.2s, box-shadow 0.2s;
  overflow-y: auto;
}
.reply-input::placeholder { color: var(--text-light); }
.reply-input:focus { border-color: var(--accent); box-shadow: 0 0 0 3px rgba(79,70,229,0.12); background: #fff; }

.send-btn {
  flex-shrink: 0;
  width: 44px; height: 44px;
  border: none; border-radius: 12px;
  background: var(--accent); color: #fff;
  cursor: pointer;
  display: flex; align-items: center; justify-content: center;
  transition: background 0.2s, transform 0.15s, box-shadow 0.2s;
  box-shadow: var(--shadow-sm);
}
.send-btn:hover { background: var(--accent-hover); box-shadow: var(--shadow-md); transform: translateY(-1px); }
.send-btn:active { transform: translateY(0); }

.reply-hint { font-size: 0.68rem; color: var(--text-light); margin-top: 5px; padding-left: 2px; }
.reply-hint kbd {
  background: #f3f4f6;
  border: 1px solid #e5e7eb;
  border-radius: 4px;
  padding: 1px 5px;
  font-family: var(--font-mono);
  font-size: 0.65rem;
  color: var(--text-mid);
}

.error-bubble {
  background: #fef2f2;
  border: 1px solid #fecaca;
  color: #b91c1c;
  border-radius: var(--radius-bubble);
  padding: 10px 14px;
  font-size: 0.85rem;
  align-self: center;
  text-align: center;
  box-shadow: var(--shadow-sm);
  animation: slideIn 0.2s ease-out;
}

/* ── Erklärung-Popup ─────────────────────────── */
.popup-overlay {
  display: none;
  position: fixed;
  inset: 0;
  background: rgba(30,27,75,0.45);
  backdrop-filter: blur(4px);
  z-index: 200;
  align-items: center;
  justify-content: center;
  padding: 20px;
}
.popup-overlay.open { display: flex; }

.popup-box {
  background: #fff;
  border-radius: 20px;
  box-shadow: var(--shadow-lg);
  width: 100%;
  max-width: 520px;
  max-height: 80dvh;
  display: flex;
  flex-direction: column;
  animation: popIn 0.25s cubic-bezier(0.34,1.56,0.64,1);
}
@keyframes popIn {
  from { opacity: 0; transform: scale(0.88); }
  to   { opacity: 1; transform: scale(1); }
}

.popup-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 20px 12px;
  border-bottom: 1px solid var(--border);
}
.popup-title {
  font-weight: 800;
  font-size: 1rem;
  color: var(--text-dark);
}
.popup-close {
  background: var(--bg-tutor);
  border: none;
  border-radius: 8px;
  width: 30px; height: 30px;
  font-size: 0.85rem;
  cursor: pointer;
  color: var(--text-mid);
  display: flex; align-items: center; justify-content: center;
  transition: background 0.15s;
}
.popup-close:hover { background: var(--accent-soft); color: var(--accent); }

.popup-body {
  padding: 18px 20px;
  overflow-y: auto;
  font-size: 0.92rem;
  line-height: 1.7;
  color: var(--text-dark);
}
.popup-body::-webkit-scrollbar { width: 3px; }
.popup-body::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }

.popup-loading {
  display: flex;
  align-items: center;
  gap: 12px;
  color: var(--text-mid);
  font-size: 0.85rem;
  font-weight: 600;
}

/* ── Responsive ──────────────────────────────── */
@media (max-width: 680px) {
  .sidebar-toggle { display: flex; }

  .sidebar {
    position: fixed;
    top: 57px;
    left: 0;
    bottom: 0;
    z-index: 150;
    transform: translateX(-100%);
    box-shadow: var(--shadow-lg);
  }
  .sidebar.open { transform: translateX(0); }

  .message-row { max-width: 90%; }
  .task-input-area { padding: 12px 14px; }
  .chat-container { padding: 14px 12px; }
}