/* ============================================================
   conversation.css — 영어회화 AI 실습 전용 스타일
   나사렛대학교 Database and Information Systems
   ============================================================ */

@import url('../../css/variables.css');

/* ============================================================
   1. Reset & Base
   ============================================================ */

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

html {
    font-size: 16px;
    scroll-behavior: smooth;
}

body {
    font-family: var(--font-body);
    font-size: 0.9375rem;
    line-height: 1.7;
    color: var(--color-text);
    background-color: var(--color-bg);
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

ul, ol { list-style: none; }

a { text-decoration: none; color: var(--color-link); }
a:hover { text-decoration: underline; }

button {
    font-family: var(--font-body);
    cursor: pointer;
    border: none;
    background: none;
}

:focus-visible {
    outline: 2px solid var(--color-link);
    outline-offset: 2px;
}

/* ============================================================
   2. Layout Variables
   ============================================================ */

:root {
    --conv-container-max: 1140px;
    --conv-header-height: 56px;
    --chat-topbar-height: 56px;
    --chat-input-height: 120px;
    --radius-sm: 4px;
    --radius-md: 8px;
    --radius-lg: 12px;
    --radius-xl: 20px;
    --shadow-sm: 0 1px 3px rgba(0,0,0,0.08);
    --shadow-md: 0 4px 12px rgba(0,0,0,0.10);
    --shadow-lg: 0 8px 24px rgba(0,0,0,0.12);
    --color-beginner: #16a34a;
    --color-beginner-bg: #dcfce7;
    --color-intermediate: #2563eb;
    --color-intermediate-bg: #dbeafe;
    --color-advanced: #7c3aed;
    --color-advanced-bg: #ede9fe;
    --transition-fast: 0.15s ease;
    --transition-normal: 0.25s ease;
}

/* ============================================================
   3. Container
   ============================================================ */

.conv-container {
    width: 100%;
    max-width: var(--conv-container-max);
    margin-inline: auto;
    padding-inline: var(--sp-lg);
}

/* ============================================================
   4. Header (Index / History pages)
   ============================================================ */

.conv-header {
    height: var(--conv-header-height);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    position: sticky;
    top: 0;
    z-index: 100;
}

.conv-header-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    max-width: var(--conv-container-max);
    margin-inline: auto;
    padding-inline: var(--sp-lg);
}

.conv-header-logo {
    display: flex;
    flex-direction: column;
    color: var(--color-text);
    text-decoration: none;
    line-height: 1.3;
}

.conv-header-logo:hover { text-decoration: none; }

.conv-header-logo-text {
    font-size: 0.9375rem;
    font-weight: 700;
    color: var(--color-text);
}

.conv-header-logo-sub {
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.conv-header-nav {
    display: flex;
    gap: var(--sp-xs);
}

.conv-header-nav-link {
    padding: var(--sp-xs) var(--sp-md);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-muted);
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast), background var(--transition-fast);
}

.conv-header-nav-link:hover {
    color: var(--color-text);
    background: var(--color-bg-alt);
    text-decoration: none;
}

/* ============================================================
   5. Main content area
   ============================================================ */

.conv-main {
    min-height: calc(100vh - var(--conv-header-height) - 60px);
}

/* ============================================================
   6. Student Info Section
   ============================================================ */

.student-info-section {
    background: var(--color-bg-alt);
    border-bottom: 1px solid var(--color-border);
    padding-block: var(--sp-xl);
}

.student-info-card {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--sp-xl);
}

.student-info-title {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--sp-xs);
}

.student-info-desc {
    font-size: 0.875rem;
    color: var(--color-text-muted);
    margin-bottom: var(--sp-lg);
}

.student-form-row {
    display: flex;
    align-items: flex-end;
    gap: var(--sp-md);
    flex-wrap: wrap;
}

.form-field {
    display: flex;
    flex-direction: column;
    gap: var(--sp-xs);
    flex: 1;
    min-width: 160px;
    max-width: 280px;
}

.form-label {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-text-muted);
}

.form-input {
    padding: var(--sp-sm) var(--sp-md);
    font-family: var(--font-body);
    font-size: 0.9375rem;
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.form-input:focus {
    outline: none;
    border-color: var(--color-link);
    box-shadow: 0 0 0 3px rgba(0, 85, 170, 0.12);
}

.form-input::placeholder {
    color: var(--color-text-light);
}

.btn-save-student {
    padding: var(--sp-sm) var(--sp-xl);
    background: var(--color-link);
    color: #fff;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
    white-space: nowrap;
    height: 40px;
    flex-shrink: 0;
}

.btn-save-student:hover {
    background: var(--color-link-hover);
}

.form-hint {
    margin-top: var(--sp-sm);
    font-size: 0.8125rem;
    color: var(--color-beginner);
    font-weight: 500;
}

/* ============================================================
   7. Scenario Section
   ============================================================ */

.scenario-section {
    padding-block: var(--sp-2xl);
}

.scenario-section-header {
    margin-bottom: var(--sp-xl);
}

.scenario-section-title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--sp-xs);
}

.scenario-section-desc {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
}

/* ============================================================
   8. Filter Area
   ============================================================ */

.filter-area {
    margin-bottom: var(--sp-xl);
}

.filter-row {
    display: flex;
    flex-wrap: wrap;
    gap: var(--sp-lg);
    padding: var(--sp-md) var(--sp-lg);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.filter-group {
    display: flex;
    align-items: center;
    gap: var(--sp-md);
    flex-wrap: wrap;
}

.filter-group-label {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-text-muted);
    white-space: nowrap;
    min-width: 48px;
}

.filter-tabs {
    display: flex;
    flex-wrap: wrap;
    gap: 6px;
}

.filter-tab {
    display: inline-flex;
    align-items: center;
    gap: 5px;
    padding: 5px 14px;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
    cursor: pointer;
}

.filter-tab:hover {
    color: var(--color-text);
    border-color: var(--color-text-muted);
}

.filter-tab.active {
    color: var(--color-bg);
    background: var(--color-text);
    border-color: var(--color-text);
}

.difficulty-dot {
    display: inline-block;
    width: 7px;
    height: 7px;
    border-radius: 50%;
    flex-shrink: 0;
}

.difficulty-dot--beginner  { background: var(--color-beginner); }
.difficulty-dot--intermediate { background: var(--color-intermediate); }
.difficulty-dot--advanced  { background: var(--color-advanced); }

/* ============================================================
   9. Scenario Grid & Cards
   ============================================================ */

.scenario-grid {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: var(--sp-lg);
    margin-bottom: var(--sp-xl);
}

.scenario-card {
    display: flex;
    flex-direction: column;
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    padding: var(--sp-lg);
    cursor: pointer;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast), transform var(--transition-fast);
    text-decoration: none;
    color: inherit;
}

.scenario-card:hover {
    border-color: var(--color-link);
    box-shadow: var(--shadow-md);
    transform: translateY(-2px);
    text-decoration: none;
}

.scenario-card:focus-visible {
    outline: 2px solid var(--color-link);
    outline-offset: 2px;
}

.scenario-card-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--sp-sm);
    margin-bottom: var(--sp-sm);
}

.scenario-card-icon {
    font-size: 1.75rem;
    line-height: 1;
    flex-shrink: 0;
}

.difficulty-badge {
    display: inline-block;
    padding: 2px 10px;
    font-size: 0.6875rem;
    font-weight: 700;
    border-radius: 20px;
    letter-spacing: 0.02em;
    white-space: nowrap;
    flex-shrink: 0;
}

.difficulty-badge--beginner {
    background: var(--color-beginner-bg);
    color: var(--color-beginner);
}

.difficulty-badge--intermediate {
    background: var(--color-intermediate-bg);
    color: var(--color-intermediate);
}

.difficulty-badge--advanced {
    background: var(--color-advanced-bg);
    color: var(--color-advanced);
}

.scenario-card-title {
    font-size: 1rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: var(--sp-xs);
    line-height: 1.4;
}

.scenario-card-title-en {
    display: block;
    font-size: 0.75rem;
    font-weight: 400;
    color: var(--color-text-muted);
    margin-top: 2px;
}

.scenario-card-desc {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
    line-height: 1.6;
    margin-bottom: var(--sp-md);
    flex: 1;
}

.scenario-card-footer {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-sm);
    padding-top: var(--sp-sm);
    border-top: 1px solid var(--color-border);
    margin-top: auto;
}

.scenario-card-meta {
    display: flex;
    gap: var(--sp-md);
}

.scenario-meta-item {
    font-size: 0.75rem;
    color: var(--color-text-light);
    display: flex;
    align-items: center;
    gap: 3px;
}

.scenario-meta-icon {
    font-size: 0.8125rem;
}

.scenario-card-start {
    font-size: 0.8125rem;
    font-weight: 600;
    color: var(--color-link);
    display: flex;
    align-items: center;
    gap: 2px;
    transition: gap var(--transition-fast);
}

.scenario-card:hover .scenario-card-start {
    gap: 5px;
}

/* ============================================================
   10. Loading / Error / Empty States
   ============================================================ */

.scenarios-loading,
.history-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--sp-md);
    padding: var(--sp-2xl);
    color: var(--color-text-muted);
    font-size: 0.9375rem;
}

.loading-spinner {
    width: 24px;
    height: 24px;
    border: 2px solid var(--color-border);
    border-top-color: var(--color-link);
    border-radius: 50%;
    animation: spin 0.7s linear infinite;
    flex-shrink: 0;
}

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

.scenarios-error,
.history-error {
    text-align: center;
    padding: var(--sp-2xl);
}

.error-message {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    margin-bottom: var(--sp-md);
}

.btn-retry {
    padding: var(--sp-sm) var(--sp-xl);
    background: var(--color-link);
    color: #fff;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    transition: background var(--transition-fast);
}

.btn-retry:hover {
    background: var(--color-link-hover);
}

.scenarios-empty,
.history-empty {
    padding: var(--sp-2xl);
    text-align: center;
    color: var(--color-text-muted);
}

.empty-state-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--sp-md);
    padding: var(--sp-2xl);
}

.empty-state-icon {
    font-size: 2.5rem;
    line-height: 1;
}

.empty-state-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
}

.empty-state-desc {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    text-align: center;
}

/* ============================================================
   11. History Link
   ============================================================ */

.history-link-area {
    text-align: center;
    padding-top: var(--sp-lg);
    border-top: 1px solid var(--color-border);
}

.btn-history-link {
    font-size: 0.9375rem;
    font-weight: 500;
    color: var(--color-link);
    padding: var(--sp-sm) var(--sp-lg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    display: inline-block;
    transition: background var(--transition-fast), border-color var(--transition-fast);
}

.btn-history-link:hover {
    background: var(--color-bg-alt);
    border-color: var(--color-link);
    text-decoration: none;
}

/* ============================================================
   12. Footer
   ============================================================ */

.conv-footer {
    border-top: 1px solid var(--color-border);
    padding-block: var(--sp-xl);
    background: var(--color-bg);
}

.conv-footer-text {
    font-size: 0.8125rem;
    color: var(--color-text-light);
    text-align: center;
}

/* ============================================================
   13. Chat Page — Top Bar
   ============================================================ */

body.chat-page {
    display: flex;
    flex-direction: column;
    height: 100dvh;
    height: 100vh;
    overflow: hidden;
    background: #f7f8fa;
}

.chat-topbar {
    height: var(--chat-topbar-height);
    background: var(--color-bg);
    border-bottom: 1px solid var(--color-border);
    flex-shrink: 0;
    z-index: 50;
}

.chat-topbar-inner {
    display: flex;
    align-items: center;
    justify-content: space-between;
    height: 100%;
    padding-inline: var(--sp-md);
    gap: var(--sp-md);
}

.chat-back-btn {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    color: var(--color-text-muted);
    font-size: 0.875rem;
    font-weight: 500;
    padding: var(--sp-xs) var(--sp-sm);
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast), background var(--transition-fast);
    flex-shrink: 0;
    text-decoration: none;
}

.chat-back-btn:hover {
    color: var(--color-text);
    background: var(--color-bg-alt);
    text-decoration: none;
}

.chat-topbar-info {
    display: flex;
    align-items: center;
    gap: var(--sp-sm);
    flex: 1;
    min-width: 0;
    justify-content: center;
}

.chat-topbar-title {
    font-size: 0.9375rem;
    font-weight: 700;
    color: var(--color-text);
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
    max-width: 260px;
}

.chat-topbar-right {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    gap: var(--sp-sm);
}

.chat-turn-counter {
    font-size: 0.8125rem;
    font-family: var(--font-mono);
    color: var(--color-text-muted);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: 20px;
    padding: 2px 10px;
    white-space: nowrap;
}

/* ============================================================
   14. Chat Main Layout
   ============================================================ */

.chat-main {
    display: flex;
    flex-direction: column;
    flex: 1;
    min-height: 0;
    overflow: hidden;
    position: relative;
}

.chat-messages-area {
    flex: 1;
    overflow-y: auto;
    overflow-x: hidden;
    padding: var(--sp-lg) var(--sp-md);
    scroll-behavior: smooth;
}

.chat-messages-list {
    display: flex;
    flex-direction: column;
    gap: var(--sp-md);
    max-width: 800px;
    margin-inline: auto;
}

/* ============================================================
   15. Chat Message Bubbles
   ============================================================ */

.chat-message {
    display: flex;
    gap: var(--sp-sm);
    max-width: 78%;
    animation: messageIn 0.2s ease;
}

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

.chat-message--ai {
    align-self: flex-start;
    flex-direction: row;
}

.chat-message--user {
    align-self: flex-end;
    flex-direction: row-reverse;
}

.chat-message--system {
    align-self: center;
    max-width: 90%;
}

.chat-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1rem;
    flex-shrink: 0;
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    margin-top: 2px;
}

.chat-bubble-wrap {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.chat-message--user .chat-bubble-wrap {
    align-items: flex-end;
}

.chat-bubble {
    padding: var(--sp-sm) var(--sp-md);
    border-radius: var(--radius-lg);
    font-size: 0.9375rem;
    line-height: 1.65;
    word-break: break-word;
    white-space: pre-wrap;
}

.chat-message--ai .chat-bubble {
    background: var(--color-bg);
    color: var(--color-text);
    border: 1px solid var(--color-border);
    border-top-left-radius: var(--radius-sm);
}

.chat-message--user .chat-bubble {
    background: var(--color-link);
    color: #fff;
    border-top-right-radius: var(--radius-sm);
}

.chat-message--system .chat-bubble {
    background: #fef3c7;
    color: #92400e;
    border: 1px solid #fde68a;
    border-radius: var(--radius-md);
    font-size: 0.875rem;
    text-align: center;
}

.chat-time {
    font-size: 0.6875rem;
    color: var(--color-text-light);
    padding-inline: 2px;
}

/* Typing indicator */
.chat-typing {
    display: flex;
    align-items: center;
    gap: var(--sp-sm);
    padding: var(--sp-sm) var(--sp-md);
    max-width: 78%;
    align-self: flex-start;
}

.chat-typing-bubble {
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    border-top-left-radius: var(--radius-sm);
    padding: var(--sp-sm) var(--sp-md);
    display: flex;
    align-items: center;
    gap: 4px;
}

.typing-dot {
    width: 6px;
    height: 6px;
    background: var(--color-text-light);
    border-radius: 50%;
    animation: typingBounce 1.2s ease-in-out infinite;
}

.typing-dot:nth-child(2) { animation-delay: 0.2s; }
.typing-dot:nth-child(3) { animation-delay: 0.4s; }

@keyframes typingBounce {
    0%, 60%, 100% { transform: translateY(0); opacity: 0.5; }
    30% { transform: translateY(-5px); opacity: 1; }
}

/* Streaming cursor */
.stream-cursor {
    display: inline-block;
    width: 2px;
    height: 1em;
    background: var(--color-text-muted);
    margin-left: 2px;
    vertical-align: text-bottom;
    animation: cursorBlink 0.8s step-end infinite;
}

@keyframes cursorBlink {
    0%, 100% { opacity: 1; }
    50% { opacity: 0; }
}

/* ============================================================
   16. Chat Hint Banner
   ============================================================ */

.chat-hint-banner {
    background: #eff6ff;
    border-top: 1px solid #bfdbfe;
    border-bottom: 1px solid #bfdbfe;
    padding: var(--sp-sm) var(--sp-lg);
    font-size: 0.875rem;
    color: #1e40af;
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-md);
    flex-shrink: 0;
}

.chat-hint-close {
    font-size: 0.875rem;
    color: #93c5fd;
    cursor: pointer;
    flex-shrink: 0;
    padding: 2px 6px;
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast);
}

.chat-hint-close:hover { color: #1e40af; }

/* ============================================================
   17. Chat Input Area
   ============================================================ */

.chat-input-area {
    background: var(--color-bg);
    border-top: 1px solid var(--color-border);
    flex-shrink: 0;
    padding: var(--sp-md);
}

.chat-input-inner {
    max-width: 800px;
    margin-inline: auto;
    display: flex;
    flex-direction: column;
    gap: var(--sp-sm);
}

.chat-input-row {
    display: flex;
    gap: var(--sp-sm);
    align-items: flex-end;
}

.chat-textarea {
    flex: 1;
    min-height: 42px;
    max-height: 120px;
    padding: var(--sp-sm) var(--sp-md);
    font-family: var(--font-body);
    font-size: 0.9375rem;
    line-height: 1.5;
    color: var(--color-text);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-lg);
    resize: none;
    overflow-y: auto;
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.chat-textarea:focus {
    outline: none;
    border-color: var(--color-link);
    box-shadow: 0 0 0 3px rgba(0, 85, 170, 0.10);
}

.chat-textarea::placeholder {
    color: var(--color-text-light);
    font-size: 0.875rem;
}

.chat-send-btn {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    background: var(--color-link);
    color: #fff;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: background var(--transition-fast), transform var(--transition-fast);
}

.chat-send-btn:hover:not(:disabled) {
    background: var(--color-link-hover);
    transform: scale(1.05);
}

.chat-send-btn:disabled {
    background: var(--color-border);
    color: var(--color-text-light);
    cursor: not-allowed;
}

.chat-input-actions {
    display: flex;
    align-items: center;
    gap: var(--sp-xs);
    flex-wrap: wrap;
}

.btn-chat-action {
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-text-muted);
    padding: 4px 10px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    background: var(--color-bg);
    transition: color var(--transition-fast), background var(--transition-fast);
}

.btn-chat-action:hover {
    color: var(--color-text);
    background: var(--color-bg-alt);
}

.btn-chat-action--end {
    color: var(--color-beginner);
    border-color: #bbf7d0;
}

.btn-chat-action--end:hover {
    background: var(--color-beginner-bg);
}

.char-counter {
    margin-left: auto;
    font-size: 0.75rem;
    color: var(--color-text-light);
    font-family: var(--font-mono);
}

/* ============================================================
   18. Chat Loading / Error Overlay
   ============================================================ */

.chat-loading-overlay,
.chat-error-overlay {
    position: fixed;
    inset: 0;
    background: rgba(255, 255, 255, 0.95);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 200;
}

.chat-loading-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--sp-md);
    color: var(--color-text-muted);
    font-size: 0.9375rem;
}

.chat-error-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--sp-md);
    max-width: 380px;
    text-align: center;
    padding: var(--sp-2xl);
}

.chat-error-icon {
    font-size: 2.5rem;
}

.chat-error-title {
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
}

.chat-error-msg {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
    line-height: 1.6;
}

.chat-error-actions {
    display: flex;
    gap: var(--sp-md);
    flex-wrap: wrap;
    justify-content: center;
}

/* ============================================================
   19. Common Buttons
   ============================================================ */

.btn-chat-primary {
    display: inline-block;
    padding: var(--sp-sm) var(--sp-xl);
    background: var(--color-link);
    color: #fff;
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    transition: background var(--transition-fast);
    text-decoration: none;
}

.btn-chat-primary:hover {
    background: var(--color-link-hover);
    text-decoration: none;
    color: #fff;
}

.btn-chat-secondary {
    display: inline-block;
    padding: var(--sp-sm) var(--sp-xl);
    background: var(--color-bg);
    color: var(--color-text);
    font-size: 0.875rem;
    font-weight: 600;
    border-radius: var(--radius-sm);
    border: 1px solid var(--color-border);
    cursor: pointer;
    transition: background var(--transition-fast), border-color var(--transition-fast);
    text-decoration: none;
}

.btn-chat-secondary:hover {
    background: var(--color-bg-alt);
    border-color: var(--color-text-muted);
    text-decoration: none;
}

/* ============================================================
   20. Chat Ended Panel
   ============================================================ */

.chat-ended-panel {
    position: fixed;
    inset: 0;
    background: rgba(255, 255, 255, 0.97);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 150;
    animation: fadeIn 0.3s ease;
}

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

.chat-ended-box {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: var(--sp-md);
    max-width: 420px;
    text-align: center;
    padding: var(--sp-2xl);
}

.chat-ended-icon {
    font-size: 3rem;
    line-height: 1;
    animation: popIn 0.4s cubic-bezier(0.175, 0.885, 0.32, 1.275);
}

@keyframes popIn {
    from { transform: scale(0.5); opacity: 0; }
    to { transform: scale(1); opacity: 1; }
}

.chat-ended-title {
    font-family: var(--font-heading);
    font-size: 1.375rem;
    font-weight: 700;
    color: var(--color-text);
}

.chat-ended-desc {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
}

.chat-ended-stats {
    display: flex;
    gap: var(--sp-xl);
    padding: var(--sp-lg) var(--sp-xl);
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
}

.ended-stat {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 2px;
}

.ended-stat-value {
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    font-family: var(--font-mono);
}

.ended-stat-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
}

.chat-ended-actions {
    display: flex;
    gap: var(--sp-md);
    flex-wrap: wrap;
    justify-content: center;
}

/* ============================================================
   21. History Page
   ============================================================ */

.history-page-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: var(--sp-md);
    padding-block: var(--sp-xl);
    border-bottom: 1px solid var(--color-border);
    margin-bottom: var(--sp-xl);
}

.history-page-title {
    font-family: var(--font-heading);
    font-size: 1.5rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 4px;
}

.history-page-student {
    font-size: 0.9375rem;
    color: var(--color-text-muted);
}

/* Stats Cards */
.history-stats {
    display: grid;
    grid-template-columns: repeat(4, 1fr);
    gap: var(--sp-md);
    margin-bottom: var(--sp-xl);
}

.stat-card {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 4px;
    padding: var(--sp-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    text-align: center;
}

.stat-value {
    font-size: 1.75rem;
    font-weight: 700;
    color: var(--color-text);
    font-family: var(--font-mono);
    line-height: 1;
}

.stat-label {
    font-size: 0.75rem;
    color: var(--color-text-muted);
    font-weight: 500;
}

/* Session List */
.history-list-header {
    margin-bottom: var(--sp-md);
}

.history-list-title {
    font-family: var(--font-heading);
    font-size: 1.125rem;
    font-weight: 700;
    color: var(--color-text);
}

.session-list {
    display: flex;
    flex-direction: column;
    gap: var(--sp-sm);
    margin-bottom: var(--sp-xl);
}

.session-item {
    display: flex;
    align-items: center;
    gap: var(--sp-md);
    padding: var(--sp-md) var(--sp-lg);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-md);
    transition: border-color var(--transition-fast), box-shadow var(--transition-fast);
}

.session-item:hover {
    border-color: var(--color-text-muted);
    box-shadow: var(--shadow-sm);
}

.session-item-icon {
    font-size: 1.5rem;
    flex-shrink: 0;
    width: 40px;
    text-align: center;
}

.session-item-body {
    flex: 1;
    min-width: 0;
}

.session-item-title {
    font-size: 0.9375rem;
    font-weight: 600;
    color: var(--color-text);
    margin-bottom: 3px;
    white-space: nowrap;
    overflow: hidden;
    text-overflow: ellipsis;
}

.session-item-meta {
    display: flex;
    align-items: center;
    flex-wrap: wrap;
    gap: var(--sp-sm);
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.session-item-meta-sep {
    color: var(--color-border);
}

.session-status-badge {
    display: inline-block;
    padding: 1px 8px;
    font-size: 0.6875rem;
    font-weight: 600;
    border-radius: 20px;
}

.session-status-badge--done {
    background: var(--color-beginner-bg);
    color: var(--color-beginner);
}

.session-status-badge--incomplete {
    background: #f3f4f6;
    color: var(--color-text-muted);
}

.session-item-actions {
    display: flex;
    gap: var(--sp-sm);
    flex-shrink: 0;
}

.btn-session-view {
    padding: 5px 14px;
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--color-link);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-bg);
    transition: background var(--transition-fast), border-color var(--transition-fast);
    cursor: pointer;
}

.btn-session-view:hover {
    background: var(--color-bg-alt);
    border-color: var(--color-link);
}

.btn-session-mp3 {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    width: 32px;
    height: 32px;
    font-size: 1rem;
    color: var(--color-link);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    background: var(--color-bg);
    text-decoration: none;
    transition: background var(--transition-fast), border-color var(--transition-fast);
    cursor: pointer;
}

.btn-session-mp3:hover {
    background: var(--color-bg-alt);
    border-color: var(--color-link);
    text-decoration: none;
}

.btn-mp3-download {
    display: inline-flex;
    align-items: center;
    gap: 4px;
    text-decoration: none;
}

.btn-mp3-download:hover {
    text-decoration: none;
}

/* Pagination */
.pagination {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--sp-xs);
    margin-bottom: var(--sp-xl);
}

.page-btn {
    display: inline-flex;
    align-items: center;
    justify-content: center;
    min-width: 36px;
    height: 36px;
    padding: 0 var(--sp-sm);
    font-size: 0.875rem;
    font-weight: 500;
    color: var(--color-text-muted);
    background: var(--color-bg);
    border: 1px solid var(--color-border);
    border-radius: var(--radius-sm);
    cursor: pointer;
    transition: color var(--transition-fast), background var(--transition-fast), border-color var(--transition-fast);
}

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

.page-btn.active {
    background: var(--color-text);
    color: var(--color-bg);
    border-color: var(--color-text);
}

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

/* ============================================================
   22. Message Modal
   ============================================================ */

.modal-overlay {
    position: fixed;
    inset: 0;
    background: rgba(0, 0, 0, 0.45);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 300;
    padding: var(--sp-md);
    animation: fadeIn 0.2s ease;
}

.modal-box {
    background: var(--color-bg);
    border-radius: var(--radius-lg);
    box-shadow: var(--shadow-lg);
    width: 100%;
    max-width: 600px;
    max-height: 85vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
    animation: slideUp 0.25s ease;
}

@keyframes slideUp {
    from { transform: translateY(24px); opacity: 0; }
    to { transform: translateY(0); opacity: 1; }
}

.modal-header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: var(--sp-md);
    padding: var(--sp-lg) var(--sp-xl);
    border-bottom: 1px solid var(--color-border);
    flex-shrink: 0;
}

.modal-title {
    font-family: var(--font-heading);
    font-size: 1.0625rem;
    font-weight: 700;
    color: var(--color-text);
    margin-bottom: 2px;
}

.modal-subtitle {
    font-size: 0.8125rem;
    color: var(--color-text-muted);
}

.modal-close-btn {
    color: var(--color-text-light);
    padding: var(--sp-xs);
    border-radius: var(--radius-sm);
    transition: color var(--transition-fast), background var(--transition-fast);
    flex-shrink: 0;
}

.modal-close-btn:hover {
    color: var(--color-text);
    background: var(--color-bg-alt);
}

.modal-body {
    overflow-y: auto;
    padding: var(--sp-lg) var(--sp-xl);
    flex: 1;
}

.modal-loading {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: var(--sp-md);
    padding: var(--sp-2xl);
    color: var(--color-text-muted);
}

.modal-messages {
    display: flex;
    flex-direction: column;
    gap: var(--sp-md);
}

.modal-message {
    display: flex;
    flex-direction: column;
    gap: 3px;
}

.modal-message--user {
    align-items: flex-end;
}

.modal-message--ai {
    align-items: flex-start;
}

.modal-message-role {
    font-size: 0.6875rem;
    font-weight: 600;
    color: var(--color-text-light);
    text-transform: uppercase;
    letter-spacing: 0.04em;
    padding-inline: 2px;
}

.modal-message-bubble {
    max-width: 85%;
    padding: var(--sp-sm) var(--sp-md);
    border-radius: var(--radius-lg);
    font-size: 0.875rem;
    line-height: 1.65;
    white-space: pre-wrap;
    word-break: break-word;
}

.modal-message--ai .modal-message-bubble {
    background: var(--color-bg-alt);
    border: 1px solid var(--color-border);
    border-top-left-radius: var(--radius-sm);
}

.modal-message--user .modal-message-bubble {
    background: var(--color-link);
    color: #fff;
    border-top-right-radius: var(--radius-sm);
}

.modal-message-time {
    font-size: 0.6875rem;
    color: var(--color-text-light);
    padding-inline: 2px;
}

/* ============================================================
   23. Responsive — Tablet (max 900px)
   ============================================================ */

@media (max-width: 900px) {
    .scenario-grid {
        grid-template-columns: repeat(2, 1fr);
    }

    .history-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .chat-topbar-title {
        max-width: 180px;
    }
}

/* ============================================================
   24. Responsive — Mobile (max 600px)
   ============================================================ */

@media (max-width: 600px) {
    .conv-container {
        padding-inline: var(--sp-md);
    }

    .conv-header-logo-sub {
        display: none;
    }

    .conv-header-nav-link:not(:last-child) {
        display: none;
    }

    .student-form-row {
        flex-direction: column;
        align-items: stretch;
    }

    .form-field {
        max-width: 100%;
    }

    .btn-save-student {
        width: 100%;
    }

    .scenario-section-title {
        font-size: 1.25rem;
    }

    .scenario-grid {
        grid-template-columns: 1fr;
    }

    .filter-row {
        flex-direction: column;
        gap: var(--sp-sm);
    }

    .history-stats {
        grid-template-columns: repeat(2, 1fr);
    }

    .session-item {
        flex-wrap: wrap;
    }

    .session-item-actions {
        width: 100%;
        justify-content: flex-end;
    }

    .chat-topbar-title {
        max-width: 130px;
        font-size: 0.875rem;
    }

    .chat-back-label {
        display: none;
    }

    .chat-message {
        max-width: 92%;
    }

    .chat-input-area {
        padding: var(--sp-sm);
    }

    .btn-chat-action {
        font-size: 0.75rem;
        padding: 3px 8px;
    }

    .modal-box {
        max-height: 92vh;
    }

    .modal-header {
        padding: var(--sp-md) var(--sp-lg);
    }

    .modal-body {
        padding: var(--sp-md) var(--sp-lg);
    }

    .chat-ended-stats {
        gap: var(--sp-lg);
        padding: var(--sp-md) var(--sp-lg);
    }

    .history-page-header {
        flex-direction: column;
        align-items: flex-start;
    }

    .chat-topbar-inner {
        padding-inline: var(--sp-sm);
    }
}

/* ============================================================
   25. Responsive — Small Mobile (max 380px)
   ============================================================ */

@media (max-width: 380px) {
    html { font-size: 15px; }

    .scenario-card-title {
        font-size: 0.9375rem;
    }

    .history-stats {
        grid-template-columns: 1fr 1fr;
    }
}

/* ============================================================
   26. Utility
   ============================================================ */

.visually-hidden {
    position: absolute;
    width: 1px;
    height: 1px;
    padding: 0;
    margin: -1px;
    overflow: hidden;
    clip: rect(0,0,0,0);
    white-space: nowrap;
    border: 0;
}

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

.text-center {
    text-align: center;
}

/* ============================================================
   Voice Controls
   ============================================================ */

.voice-controls {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 6px 0 8px;
}

.btn-voice-toggle {
    display: inline-flex;
    align-items: center;
    gap: 6px;
    padding: 6px 14px;
    border: 2px solid #d1d5db;
    border-radius: 20px;
    background: #fff;
    font-size: 0.85rem;
    font-weight: 600;
    color: #6b7280;
    cursor: pointer;
    transition: all 0.25s ease;
}

.btn-voice-toggle:hover {
    border-color: #3b82f6;
    color: #3b82f6;
}

.btn-voice-toggle.active {
    border-color: #3b82f6;
    background: #eff6ff;
    color: #2563eb;
    box-shadow: 0 0 0 3px rgba(59, 130, 246, 0.15);
}

.btn-voice-toggle.active .voice-toggle-icon {
    animation: voice-pulse 1.5s ease-in-out infinite;
}

.voice-toggle-icon {
    font-size: 1.1rem;
}

.voice-status {
    font-size: 0.8rem;
    color: #6b7280;
    font-weight: 500;
    min-height: 1.2em;
}

/* Mic button */
.chat-mic-btn {
    display: flex;
    align-items: center;
    justify-content: center;
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    background: #f3f4f6;
    color: #6b7280;
    cursor: pointer;
    flex-shrink: 0;
    transition: all 0.2s ease;
}

.chat-mic-btn:hover {
    background: #e5e7eb;
    color: #374151;
}

.chat-mic-btn.listening {
    background: #fee2e2;
    color: #ef4444;
    animation: mic-pulse 1s ease-in-out infinite;
    box-shadow: 0 0 0 4px rgba(239, 68, 68, 0.2);
}

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

@keyframes voice-pulse {
    0%, 100% { opacity: 1; }
    50% { opacity: 0.5; }
}

/* Mobile adjustments */
@media (max-width: 480px) {
    .voice-controls {
        flex-wrap: wrap;
        gap: 8px;
    }
    .voice-status {
        width: 100%;
        font-size: 0.75rem;
    }
}

/* ============================================================
   Dialogue Player
   ============================================================ */

.dialogue-player {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    background: #fff;
    border-top: 1px solid #e5e7eb;
    box-shadow: 0 -4px 20px rgba(0,0,0,0.08);
    z-index: 100;
    padding: 12px 16px 20px;
}

.dialogue-player-inner {
    max-width: 700px;
    margin: 0 auto;
}

.dialogue-speakers {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 16px;
    margin-bottom: 8px;
}

.dialogue-speaker {
    display: flex;
    align-items: center;
    gap: 6px;
}

.speaker-avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    font-size: 1.2rem;
}

.speaker-avatar--alex {
    background: #dbeafe;
}

.speaker-avatar--sarah {
    background: #fce7f3;
}

.speaker-name {
    font-weight: 600;
    font-size: 0.9rem;
    color: #374151;
}

.dialogue-vs {
    font-size: 1.2rem;
}

.dialogue-status {
    text-align: center;
    font-size: 0.85rem;
    color: #6b7280;
    margin-bottom: 10px;
    min-height: 1.4em;
}

.dialogue-controls {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 12px;
    margin-bottom: 10px;
}

.btn-dialogue {
    width: 40px;
    height: 40px;
    border: none;
    border-radius: 50%;
    background: #f3f4f6;
    cursor: pointer;
    font-size: 1.1rem;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all 0.2s;
}

.btn-dialogue:hover { background: #e5e7eb; }
.btn-dialogue:disabled { opacity: 0.4; cursor: not-allowed; }

.btn-dialogue--main {
    width: 52px;
    height: 52px;
    background: #3b82f6;
    color: white;
    font-size: 1.3rem;
    box-shadow: 0 2px 8px rgba(59,130,246,0.3);
}

.btn-dialogue--main:hover { background: #2563eb; }

.btn-dialogue-speed {
    padding: 4px 10px;
    border: 1px solid #d1d5db;
    border-radius: 12px;
    background: #fff;
    font-size: 0.8rem;
    font-weight: 600;
    color: #4b5563;
    cursor: pointer;
}

.btn-dialogue-speed:hover { background: #f3f4f6; }

.dialogue-progress {
    height: 4px;
    background: #e5e7eb;
    border-radius: 2px;
    overflow: hidden;
    margin-bottom: 10px;
}

.dialogue-progress-bar {
    height: 100%;
    background: linear-gradient(90deg, #3b82f6, #8b5cf6);
    border-radius: 2px;
    transition: width 0.5s ease;
}

.dialogue-actions {
    display: flex;
    justify-content: center;
    gap: 12px;
}

/* 메시지 영역 하단 패딩 (플레이어 높이만큼) */
.chat-page .chat-messages-area {
    padding-bottom: 220px;
}

/* Two-Speaker Message Styles */
.chat-message--alex {
    flex-direction: row;
    align-self: flex-start;
}

.chat-message--sarah {
    flex-direction: row-reverse;
    align-self: flex-end;
}

.chat-message--alex .chat-bubble {
    background: #dbeafe;
    color: #1e3a5f;
    border: none;
    border-top-left-radius: var(--radius-sm);
}

.chat-message--sarah .chat-bubble {
    background: #fce7f3;
    color: #4a1942;
    border: none;
    border-top-right-radius: var(--radius-sm);
}

.avatar-alex {
    background: #bfdbfe;
    border-color: #bfdbfe;
}

.avatar-sarah {
    background: #fbcfe8;
    border-color: #fbcfe8;
}

.speaker-label {
    display: block;
    font-size: 0.75rem;
    font-weight: 600;
    color: #6b7280;
    margin-bottom: 2px;
}

.chat-message--sarah .speaker-label {
    text-align: right;
}

.chat-message--sarah .chat-bubble-wrap {
    align-items: flex-end;
}

/* Mobile */
@media (max-width: 480px) {
    .dialogue-player {
        padding: 10px 12px 16px;
    }
    .dialogue-controls {
        gap: 8px;
    }
}