/* ============================================
   SmallTalk — Socratic AI Study Companion
   ============================================ */

:root {
  --color-bg: #faf9f7;
  --color-surface: #ffffff;
  --color-surface-hover: #f5f4f1;
  --color-border: #e8e6e1;
  --color-border-light: #f0eeea;
  --color-text: #1a1a1a;
  --color-text-secondary: #6b6560;
  --color-text-muted: #9b9590;
  --color-primary: #1a535c;
  --color-primary-hover: #15454d;
  --color-primary-light: #e8f4f6;
  --color-accent: #f4a261;
  --color-accent-light: #fef3e6;
  --color-danger: #d63031;
  --color-assistant-bg: #f0f7f8;
  --color-user-bg: #1a535c;
  --color-user-text: #ffffff;
  --radius-sm: 8px;
  --radius-md: 12px;
  --radius-lg: 20px;
  --radius-full: 9999px;
  --shadow-sm: 0 1px 3px rgba(0,0,0,0.06);
  --shadow-md: 0 4px 12px rgba(0,0,0,0.08);
  --shadow-lg: 0 8px 30px rgba(0,0,0,0.12);
  --font-sans: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
  --font-serif: 'Instrument Serif', Georgia, serif;
}

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

html, body {
  height: 100%;
  font-family: var(--font-sans);
  background: var(--color-bg);
  color: var(--color-text);
  font-size: 15px;
  line-height: 1.6;
  -webkit-font-smoothing: antialiased;
}

/* ============================================
   Modal
   ============================================ */

.modal-overlay {
  position: fixed;
  inset: 0;
  background: rgba(26, 26, 26, 0.5);
  backdrop-filter: blur(8px);
  display: flex;
  align-items: center;
  justify-content: center;
  z-index: 100;
  padding: 20px;
  animation: fadeIn 0.3s ease;
}

.hidden {
  display: none !important;
}

.modal {
  background: var(--color-surface);
  border-radius: var(--radius-lg);
  padding: 48px 40px;
  max-width: 440px;
  width: 100%;
  box-shadow: var(--shadow-lg);
  text-align: center;
  animation: slideUp 0.4s ease;
}

.modal-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.modal h2 {
  font-family: var(--font-serif);
  font-size: 28px;
  font-weight: 400;
  margin-bottom: 8px;
  letter-spacing: -0.01em;
}

.modal-subtitle {
  color: var(--color-text-secondary);
  font-size: 15px;
  margin-bottom: 24px;
}

.modal-description {
  color: var(--color-text-muted);
  font-size: 13px;
  margin-bottom: 24px;
  line-height: 1.5;
}

.modal-description a {
  color: var(--color-primary);
  text-decoration: none;
  font-weight: 500;
}

.modal-description a:hover {
  text-decoration: underline;
}

.waitlist-success-icon {
  font-size: 48px;
  margin-bottom: 16px;
}

.modal-dismiss {
  display: inline-block;
  margin-top: 14px;
  font-size: 13px;
  color: var(--color-text-muted);
  text-decoration: none;
  cursor: pointer;
  transition: color 0.2s;
}

.modal-dismiss:hover {
  color: var(--color-text-secondary);
  text-decoration: underline;
}

/* ============================================
   Forms
   ============================================ */

.input-group {
  text-align: left;
  margin-bottom: 20px;
}

.input-group label {
  display: block;
  font-size: 13px;
  font-weight: 600;
  color: var(--color-text-secondary);
  margin-bottom: 6px;
  letter-spacing: 0.02em;
}

.input-group input {
  width: 100%;
  padding: 12px 14px;
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--color-text);
  background: var(--color-bg);
  transition: border-color 0.2s, box-shadow 0.2s;
  outline: none;
}

.input-group input:focus {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

.input-group input::placeholder {
  color: var(--color-text-muted);
}

.input-hint {
  display: block;
  margin-top: 6px;
  font-size: 12px;
  color: var(--color-text-muted);
}

.input-hint a {
  color: var(--color-primary);
  text-decoration: none;
}

.input-hint a:hover {
  text-decoration: underline;
}

.error-text {
  color: var(--color-danger);
  font-size: 13px;
  margin-top: 12px;
  min-height: 20px;
}

/* ============================================
   Buttons
   ============================================ */

.btn-primary {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  gap: 8px;
  width: 100%;
  padding: 12px 24px;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 14px;
  font-weight: 600;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

.btn-primary:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.btn-primary:active:not(:disabled) {
  transform: scale(0.98);
}

.btn-primary:disabled {
  opacity: 0.5;
  cursor: not-allowed;
}

.btn-secondary {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: var(--color-primary);
  color: white;
  border: none;
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: background 0.2s, transform 0.1s;
}

.btn-secondary:hover {
  background: var(--color-primary-hover);
}

.btn-secondary:active {
  transform: scale(0.97);
}

.btn-ghost {
  display: inline-flex;
  align-items: center;
  gap: 6px;
  padding: 8px 14px;
  background: transparent;
  color: var(--color-text-secondary);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-ghost:hover:not(:disabled) {
  background: var(--color-surface-hover);
  border-color: var(--color-text-muted);
}

.btn-ghost:disabled {
  opacity: 0.4;
  cursor: not-allowed;
}

.btn-icon {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 36px;
  height: 36px;
  background: transparent;
  color: var(--color-text-secondary);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-sm);
  cursor: pointer;
  transition: all 0.2s;
}

.btn-icon:hover {
  background: var(--color-surface-hover);
  border-color: var(--color-text-muted);
}

.btn-danger {
  display: inline-flex;
  align-items: center;
  justify-content: center;
  width: 100%;
  padding: 10px 20px;
  background: transparent;
  color: var(--color-danger);
  border: 1.5px solid var(--color-danger);
  border-radius: var(--radius-sm);
  font-family: var(--font-sans);
  font-size: 13px;
  font-weight: 500;
  cursor: pointer;
  transition: all 0.2s;
}

.btn-danger:hover {
  background: var(--color-danger);
  color: white;
}

/* ============================================
   Layout
   ============================================ */

.app {
  display: flex;
  flex-direction: column;
  height: 100vh;
  max-width: 800px;
  margin: 0 auto;
}

.app.hidden {
  display: none;
}

/* ============================================
   Header
   ============================================ */

.header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  padding: 16px 24px;
  border-bottom: 1px solid var(--color-border-light);
  background: var(--color-surface);
  flex-shrink: 0;
}

.header-left {
  display: flex;
  align-items: baseline;
  gap: 10px;
}

.logo {
  font-family: var(--font-serif);
  font-size: 24px;
  font-weight: 400;
  color: var(--color-primary);
  letter-spacing: -0.02em;
}

.tagline {
  font-size: 12px;
  color: var(--color-text-muted);
  font-weight: 500;
  letter-spacing: 0.03em;
  text-transform: uppercase;
}

.header-right {
  display: flex;
  align-items: center;
  gap: 8px;
}

/* ============================================
   Chat Area
   ============================================ */

.chat-area {
  flex: 1;
  overflow-y: auto;
  padding: 0;
  scroll-behavior: smooth;
}

/* ============================================
   Welcome State
   ============================================ */

.welcome {
  display: flex;
  align-items: center;
  justify-content: center;
  min-height: 100%;
  padding: 40px 24px;
}

.welcome.hidden {
  display: none;
}

.welcome-content {
  text-align: center;
  max-width: 520px;
}

.welcome-title {
  font-family: var(--font-serif);
  font-size: 36px;
  font-weight: 400;
  color: var(--color-text);
  margin-bottom: 12px;
  letter-spacing: -0.02em;
}

.welcome-text {
  color: var(--color-text-secondary);
  font-size: 15px;
  margin-bottom: 32px;
  line-height: 1.7;
}

.topic-suggestions {
  display: flex;
  flex-wrap: wrap;
  gap: 8px;
  justify-content: center;
}

.topic-chip {
  padding: 8px 16px;
  background: var(--color-surface);
  color: var(--color-text-secondary);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-full);
  font-family: var(--font-sans);
  font-size: 13px;
  cursor: pointer;
  transition: all 0.2s;
  white-space: nowrap;
}

.topic-chip:hover {
  background: var(--color-primary-light);
  border-color: var(--color-primary);
  color: var(--color-primary);
}

/* ============================================
   Messages
   ============================================ */

.messages {
  padding: 24px;
  display: flex;
  flex-direction: column;
  gap: 20px;
}

.message {
  display: flex;
  gap: 12px;
  animation: messageIn 0.3s ease;
  max-width: 100%;
}

.message.user {
  flex-direction: row-reverse;
}

.message-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
  flex-shrink: 0;
  margin-top: 2px;
}

.message.assistant .message-avatar {
  background: var(--color-primary);
  color: white;
}

.message.user .message-avatar {
  background: var(--color-accent);
  color: white;
}

.message-bubble {
  max-width: 75%;
  padding: 12px 16px;
  border-radius: var(--radius-md);
  font-size: 14px;
  line-height: 1.65;
  word-wrap: break-word;
  overflow-wrap: break-word;
}

.message.assistant .message-bubble {
  background: var(--color-assistant-bg);
  color: var(--color-text);
  border-top-left-radius: 4px;
}

.message.user .message-bubble {
  background: var(--color-user-bg);
  color: var(--color-user-text);
  border-top-right-radius: 4px;
}

.message-bubble p {
  margin-bottom: 8px;
}

.message-bubble p:last-child {
  margin-bottom: 0;
}

.message-bubble strong {
  font-weight: 600;
}

.message-bubble em {
  font-style: italic;
}

.message-bubble code {
  background: rgba(0,0,0,0.06);
  padding: 2px 6px;
  border-radius: 4px;
  font-size: 13px;
}

.message.user .message-bubble code {
  background: rgba(255,255,255,0.15);
}

/* ============================================
   Typing Indicator
   ============================================ */

.typing-indicator {
  display: flex;
  align-items: center;
  gap: 12px;
  padding: 0 24px 16px;
}

.typing-indicator.hidden {
  display: none;
}

.typing-avatar {
  width: 32px;
  height: 32px;
  border-radius: 50%;
  background: var(--color-primary);
  color: white;
  display: flex;
  align-items: center;
  justify-content: center;
  font-size: 13px;
  font-weight: 600;
  flex-shrink: 0;
}

.typing-dots {
  display: flex;
  gap: 4px;
  padding: 12px 16px;
  background: var(--color-assistant-bg);
  border-radius: var(--radius-md);
  border-top-left-radius: 4px;
}

.typing-dots span {
  width: 7px;
  height: 7px;
  background: var(--color-text-muted);
  border-radius: 50%;
  animation: typingBounce 1.2s infinite;
}

.typing-dots span:nth-child(2) {
  animation-delay: 0.15s;
}

.typing-dots span:nth-child(3) {
  animation-delay: 0.3s;
}

/* ============================================
   Input Area
   ============================================ */

.input-area {
  padding: 16px 24px 20px;
  border-top: 1px solid var(--color-border-light);
  background: var(--color-surface);
  flex-shrink: 0;
}

.input-area.read-only {
  opacity: 0.5;
  pointer-events: none;
}

.read-only-banner {
  text-align: center;
  padding: 12px 24px;
  background: var(--color-accent-light);
  color: var(--color-text-secondary);
  font-size: 13px;
  border-top: 1px solid var(--color-border-light);
  flex-shrink: 0;
}

.input-container {
  display: flex;
  align-items: flex-end;
  gap: 10px;
  background: var(--color-bg);
  border: 1.5px solid var(--color-border);
  border-radius: var(--radius-md);
  padding: 8px 8px 8px 16px;
  transition: border-color 0.2s, box-shadow 0.2s;
}

.input-container:focus-within {
  border-color: var(--color-primary);
  box-shadow: 0 0 0 3px var(--color-primary-light);
}

#message-input {
  flex: 1;
  border: none;
  background: transparent;
  font-family: var(--font-sans);
  font-size: 14px;
  color: var(--color-text);
  resize: none;
  outline: none;
  line-height: 1.5;
  max-height: 120px;
  padding: 4px 0;
}

#message-input::placeholder {
  color: var(--color-text-muted);
}

.send-btn {
  width: 36px;
  height: 36px;
  border: none;
  background: var(--color-primary);
  color: white;
  border-radius: var(--radius-sm);
  cursor: pointer;
  display: flex;
  align-items: center;
  justify-content: center;
  transition: background 0.2s, transform 0.1s, opacity 0.2s;
  flex-shrink: 0;
}

.send-btn:hover:not(:disabled) {
  background: var(--color-primary-hover);
}

.send-btn:active:not(:disabled) {
  transform: scale(0.92);
}

.send-btn:disabled {
  opacity: 0.3;
  cursor: not-allowed;
}

.send-btn svg {
  transform: rotate(180deg);
}

.input-footer {
  text-align: center;
  font-size: 11px;
  color: var(--color-text-muted);
  margin-top: 10px;
}

/* ============================================
   Settings Panel
   ============================================ */

.settings-panel {
  position: fixed;
  inset: 0;
  background: rgba(26, 26, 26, 0.3);
  backdrop-filter: blur(4px);
  z-index: 50;
  display: flex;
  justify-content: flex-end;
  animation: fadeIn 0.2s ease;
}

.settings-panel.hidden {
  display: none;
}

.settings-content {
  width: 360px;
  max-width: 100%;
  background: var(--color-surface);
  height: 100%;
  padding: 24px;
  box-shadow: var(--shadow-lg);
  animation: slideInRight 0.3s ease;
}

.settings-header {
  display: flex;
  align-items: center;
  justify-content: space-between;
  margin-bottom: 24px;
}

.settings-header h3 {
  font-size: 18px;
  font-weight: 600;
}

.settings-body {
  display: flex;
  flex-direction: column;
  gap: 16px;
}

.settings-body hr {
  border: none;
  border-top: 1px solid var(--color-border-light);
  margin: 8px 0;
}

.settings-email-display {
  font-size: 14px;
  color: var(--color-text);
  padding: 10px 14px;
  background: var(--color-bg);
  border-radius: var(--radius-sm);
  border: 1.5px solid var(--color-border);
  word-break: break-all;
}

/* ============================================
   Animations
   ============================================ */

@keyframes fadeIn {
  from { opacity: 0; }
  to { opacity: 1; }
}

@keyframes slideUp {
  from { opacity: 0; transform: translateY(20px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes slideInRight {
  from { transform: translateX(100%); }
  to { transform: translateX(0); }
}

@keyframes messageIn {
  from { opacity: 0; transform: translateY(8px); }
  to { opacity: 1; transform: translateY(0); }
}

@keyframes typingBounce {
  0%, 60%, 100% { transform: translateY(0); }
  30% { transform: translateY(-4px); }
}

/* ============================================
   Responsive
   ============================================ */

@media (max-width: 640px) {
  .header {
    padding: 12px 16px;
  }

  .header-right .btn-secondary,
  .header-right .btn-ghost {
    padding: 8px 10px;
    font-size: 12px;
  }

  .welcome-title {
    font-size: 28px;
  }

  .messages {
    padding: 16px;
  }

  .message-bubble {
    max-width: 85%;
  }

  .input-area {
    padding: 12px 16px 16px;
  }

  .modal {
    padding: 32px 24px;
  }

  .topic-chip {
    font-size: 12px;
    padding: 6px 12px;
  }
}