/* ============================================================
   DIALOGUE — Monochrome AI Chat Interface
   Typography: IBM Plex Mono + Newsreader
   Palette: Pure black & white, light mode only
   ============================================================ */

/* --- Reset & Variables --- */
*,
*::before,
*::after {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}

:root {
    /* Monochrome scale */
    --white:        #ffffff;
    --gray-50:      #fafafa;
    --gray-100:     #f5f5f5;
    --gray-150:     #efefef;
    --gray-200:     #e5e5e5;
    --gray-300:     #d4d4d4;
    --gray-400:     #a3a3a3;
    --gray-500:     #737373;
    --gray-600:     #525252;
    --gray-700:     #404040;
    --gray-800:     #262626;
    --gray-900:     #171717;
    --black:        #0a0a0a;

    /* Semantic */
    --bg:           var(--white);
    --bg-sidebar:   var(--gray-50);
    --bg-input:     var(--gray-100);
    --bg-user-msg:  var(--gray-900);
    --bg-ai-msg:    transparent;
    --bg-hover:     var(--gray-150);
    --bg-code:      var(--gray-100);
    --border:       var(--gray-200);
    --border-focus: var(--gray-900);
    --text:         var(--gray-900);
    --text-muted:   var(--gray-500);
    --text-faint:   var(--gray-400);
    --text-inverse: var(--white);

    /* Typography */
    --font-mono:    'IBM Plex Mono', 'SF Mono', 'Fira Code', monospace;
    --font-serif:   'Newsreader', 'Georgia', serif;

    /* Dimensions */
    --sidebar-w:    260px;
    --chat-max-w:   720px;
    --input-max-w:  720px;
    --radius-sm:    6px;
    --radius-md:    12px;
    --radius-lg:    20px;
    --radius-pill:  9999px;

    /* Transitions */
    --ease-out:     cubic-bezier(0.16, 1, 0.3, 1);
    --ease-spring:  cubic-bezier(0.34, 1.56, 0.64, 1);
    --dur-fast:     150ms;
    --dur-normal:   250ms;
    --dur-slow:     400ms;
}

html {
    font-size: 16px;
    -webkit-font-smoothing: antialiased;
    -moz-osx-font-smoothing: grayscale;
}

body {
    font-family: var(--font-mono);
    font-weight: 400;
    font-size: 0.875rem;
    line-height: 1.6;
    color: var(--text);
    background: var(--bg);
    display: flex;
    height: 100dvh;
    overflow: hidden;
}

::selection {
    background: var(--gray-900);
    color: var(--white);
}

button {
    font-family: inherit;
    cursor: pointer;
    border: none;
    background: none;
    color: inherit;
}

textarea {
    font-family: inherit;
    border: none;
    background: none;
    color: inherit;
    resize: none;
}

a {
    color: inherit;
    text-decoration: none;
}


/* ============================================================
   SIDEBAR
   ============================================================ */
.sidebar {
    width: var(--sidebar-w);
    height: 100dvh;
    background: var(--bg-sidebar);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
    flex-shrink: 0;
    transition: transform var(--dur-slow) var(--ease-out);
    z-index: 100;
}

.sidebar__top {
    padding: 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
}

.sidebar__logo {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 4px 0;
}

.sidebar__logo-mark {
    width: 32px;
    height: 32px;
    background: var(--gray-900);
    border-radius: var(--radius-sm);
    display: grid;
    place-items: center;
    color: var(--white);
}

.sidebar__logo-text {
    font-size: 0.9375rem;
    font-weight: 600;
    letter-spacing: -0.02em;
}

.sidebar__new-btn {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 10px 14px;
    border: 1px dashed var(--gray-300);
    border-radius: var(--radius-md);
    font-size: 0.8125rem;
    font-weight: 500;
    color: var(--text);
    transition: all var(--dur-fast) ease;
    letter-spacing: -0.01em;
}

.sidebar__new-btn:hover {
    border-color: var(--gray-900);
    background: var(--white);
}

.sidebar__threads {
    flex: 1;
    overflow-y: auto;
    padding: 0 10px;
}

.sidebar__threads::-webkit-scrollbar {
    width: 0;
}

.sidebar__section-label {
    font-size: 0.6875rem;
    font-weight: 500;
    text-transform: uppercase;
    letter-spacing: 0.08em;
    color: var(--text-faint);
    padding: 12px 6px 6px;
}

.sidebar__thread-list {
    display: flex;
    flex-direction: column;
    gap: 1px;
}

.sidebar__thread {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 9px 10px;
    border-radius: var(--radius-sm);
    font-size: 0.8125rem;
    color: var(--text);
    transition: background var(--dur-fast) ease;
    cursor: pointer;
    overflow: hidden;
    white-space: nowrap;
    text-overflow: ellipsis;
    position: relative;
}

.sidebar__thread::before {
    content: '';
    width: 4px;
    height: 4px;
    border-radius: 50%;
    background: var(--gray-400);
    flex-shrink: 0;
}

.sidebar__thread:hover {
    background: var(--bg-hover);
}

.sidebar__thread.is-active {
    background: var(--white);
    font-weight: 500;
}

.sidebar__thread.is-active::before {
    background: var(--gray-900);
}

.sidebar__thread-text {
    overflow: hidden;
    text-overflow: ellipsis;
}

.sidebar__bottom {
    padding: 12px 16px 16px;
}

.sidebar__divider {
    height: 1px;
    background: var(--border);
    margin-bottom: 12px;
}

.sidebar__user {
    display: flex;
    align-items: center;
    gap: 10px;
    padding: 6px 4px;
}

.sidebar__avatar {
    width: 28px;
    height: 28px;
    background: var(--gray-900);
    color: var(--white);
    border-radius: 50%;
    display: grid;
    place-items: center;
    font-size: 0.6875rem;
    font-weight: 600;
}

.sidebar__username {
    font-size: 0.8125rem;
    font-weight: 500;
}


/* ============================================================
   SIDEBAR TOGGLE (Mobile)
   ============================================================ */
.sidebar-toggle {
    position: fixed;
    top: 16px;
    left: 16px;
    z-index: 200;
    width: 40px;
    height: 40px;
    border-radius: var(--radius-sm);
    background: var(--white);
    border: 1px solid var(--border);
    display: none;
    place-items: center;
    color: var(--text);
    transition: all var(--dur-fast) ease;
}

.sidebar-toggle:hover {
    background: var(--gray-100);
}


/* ============================================================
   MAIN
   ============================================================ */
.main {
    flex: 1;
    display: flex;
    flex-direction: column;
    min-width: 0;
    position: relative;
}


/* ============================================================
   WELCOME STATE
   ============================================================ */
.welcome {
    flex: 1;
    display: flex;
    align-items: center;
    justify-content: center;
    padding: 40px 24px 160px;
    animation: fadeIn var(--dur-slow) var(--ease-out);
}

.welcome__content {
    max-width: 560px;
    width: 100%;
    text-align: center;
}

.welcome__mark {
    width: 56px;
    height: 56px;
    border: 1.5px solid var(--border);
    border-radius: var(--radius-md);
    display: grid;
    place-items: center;
    margin: 0 auto 28px;
    color: var(--gray-500);
    animation: floatIn 0.6s var(--ease-out) both;
}

.welcome__title {
    font-family: var(--font-serif);
    font-size: clamp(1.75rem, 4vw, 2.5rem);
    font-weight: 300;
    letter-spacing: -0.03em;
    line-height: 1.2;
    color: var(--text);
    margin-bottom: 8px;
    animation: floatIn 0.6s var(--ease-out) 0.08s both;
}

.welcome__title span {
    font-style: italic;
}

.welcome__subtitle {
    font-size: 0.875rem;
    color: var(--text-muted);
    margin-bottom: 40px;
    animation: floatIn 0.6s var(--ease-out) 0.14s both;
}

.welcome__prompts {
    display: grid;
    grid-template-columns: 1fr 1fr;
    gap: 8px;
    animation: floatIn 0.6s var(--ease-out) 0.22s both;
}

.prompt-chip {
    display: flex;
    align-items: flex-start;
    gap: 10px;
    padding: 14px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-md);
    text-align: left;
    font-size: 0.8125rem;
    line-height: 1.5;
    color: var(--text);
    transition: all var(--dur-fast) ease;
}

.prompt-chip:hover {
    border-color: var(--gray-400);
    background: var(--gray-50);
}

.prompt-chip__icon {
    flex-shrink: 0;
    margin-top: 2px;
    color: var(--text-faint);
}


/* ============================================================
   CHAT MESSAGES
   ============================================================ */
.chat {
    flex: 1;
    overflow-y: auto;
    padding-bottom: 160px;
    scroll-behavior: smooth;
}

.chat::-webkit-scrollbar {
    width: 6px;
}

.chat::-webkit-scrollbar-track {
    background: transparent;
}

.chat::-webkit-scrollbar-thumb {
    background: var(--gray-300);
    border-radius: 3px;
}

.chat__messages {
    max-width: var(--chat-max-w);
    margin: 0 auto;
    padding: 32px 24px;
    display: flex;
    flex-direction: column;
    gap: 0;
}


/* --- Message Wrapper --- */
.message {
    display: flex;
    gap: 16px;
    padding: 24px 0;
    animation: messageIn var(--dur-normal) var(--ease-out) both;
    position: relative;
}

.message + .message {
    border-top: 1px solid var(--gray-100);
}

.message__avatar {
    width: 28px;
    height: 28px;
    border-radius: 50%;
    display: grid;
    place-items: center;
    flex-shrink: 0;
    font-size: 0.625rem;
    font-weight: 600;
    margin-top: 2px;
}

.message--user .message__avatar {
    background: var(--gray-900);
    color: var(--white);
}

.message--ai .message__avatar {
    background: var(--white);
    border: 1.5px solid var(--gray-300);
    color: var(--gray-600);
}

.message__body {
    flex: 1;
    min-width: 0;
}

.message__role {
    font-size: 0.75rem;
    font-weight: 600;
    text-transform: uppercase;
    letter-spacing: 0.06em;
    margin-bottom: 6px;
    color: var(--text);
}

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

.message__text {
    font-size: 0.875rem;
    line-height: 1.7;
    color: var(--gray-800);
}

.message__text p {
    margin-bottom: 12px;
}

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

.message__text code {
    font-family: var(--font-mono);
    font-size: 0.8125rem;
    background: var(--bg-code);
    padding: 2px 6px;
    border-radius: 4px;
    border: 1px solid var(--gray-200);
}

.message__text pre {
    background: var(--gray-900);
    color: var(--gray-100);
    padding: 16px 20px;
    border-radius: var(--radius-md);
    overflow-x: auto;
    margin: 12px 0;
    font-size: 0.8125rem;
    line-height: 1.6;
    position: relative;
}

.message__text pre code {
    background: none;
    border: none;
    padding: 0;
    color: inherit;
    font-size: inherit;
}

.message__text ul,
.message__text ol {
    padding-left: 20px;
    margin: 8px 0;
}

.message__text li {
    margin-bottom: 4px;
}

.message__text strong {
    font-weight: 600;
}

.message__text em {
    font-family: var(--font-serif);
    font-style: italic;
}


/* --- Typing Indicator --- */
.typing-indicator {
    display: inline-flex;
    gap: 4px;
    padding: 4px 0;
}

.typing-indicator__dot {
    width: 6px;
    height: 6px;
    background: var(--gray-400);
    border-radius: 50%;
    animation: typingBounce 1.2s ease-in-out infinite;
}

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

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


/* --- Message Actions --- */
.message__actions {
    display: flex;
    gap: 2px;
    margin-top: 10px;
    opacity: 0;
    transition: opacity var(--dur-fast) ease;
}

.message:hover .message__actions {
    opacity: 1;
}

.message__action-btn {
    width: 30px;
    height: 30px;
    border-radius: var(--radius-sm);
    display: grid;
    place-items: center;
    color: var(--text-faint);
    transition: all var(--dur-fast) ease;
}

.message__action-btn:hover {
    background: var(--gray-100);
    color: var(--text);
}


/* ============================================================
   INPUT AREA
   ============================================================ */
.input-area {
    position: absolute;
    bottom: 0;
    left: 0;
    right: 0;
    padding: 0 24px 20px;
    background: linear-gradient(to bottom, transparent, var(--white) 40%);
    pointer-events: none;
}

.input-area__container {
    max-width: var(--input-max-w);
    margin: 0 auto;
    pointer-events: all;
}

.input-form {
    position: relative;
}

.input-form__wrapper {
    display: flex;
    align-items: flex-end;
    gap: 8px;
    background: var(--bg-input);
    border: 1.5px solid var(--border);
    border-radius: var(--radius-lg);
    padding: 10px 12px 10px 20px;
    transition: border-color var(--dur-fast) ease, box-shadow var(--dur-fast) ease;
}

.input-form__wrapper:focus-within {
    border-color: var(--gray-900);
    box-shadow: 0 0 0 3px rgba(10, 10, 10, 0.06);
}

.input-form__textarea {
    flex: 1;
    font-size: 0.875rem;
    line-height: 1.5;
    padding: 6px 0;
    max-height: 160px;
    overflow-y: auto;
    color: var(--text);
}

.input-form__textarea::placeholder {
    color: var(--text-faint);
}

.input-form__textarea::-webkit-scrollbar {
    width: 0;
}

.input-form__send {
    width: 36px;
    height: 36px;
    border-radius: var(--radius-sm);
    background: var(--gray-900);
    color: var(--white);
    display: grid;
    place-items: center;
    flex-shrink: 0;
    transition: all var(--dur-fast) ease;
    opacity: 0.3;
    pointer-events: none;
}

.input-form__send:not(:disabled) {
    opacity: 1;
    pointer-events: all;
}

.input-form__send:not(:disabled):hover {
    background: var(--black);
    transform: scale(1.05);
}

.input-form__send:not(:disabled):active {
    transform: scale(0.95);
}

.input-area__disclaimer {
    text-align: center;
    font-size: 0.6875rem;
    color: var(--text-faint);
    margin-top: 10px;
    letter-spacing: 0.01em;
}


/* ============================================================
   ANIMATIONS
   ============================================================ */
@keyframes fadeIn {
    from { opacity: 0; }
    to   { opacity: 1; }
}

@keyframes floatIn {
    from {
        opacity: 0;
        transform: translateY(12px);
    }
    to {
        opacity: 1;
        transform: translateY(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);
    }
}

@keyframes shimmer {
    0%   { background-position: -200% 0; }
    100% { background-position: 200% 0; }
}


/* ============================================================
   COPY BUTTON (CODE BLOCKS)
   ============================================================ */
.code-block-header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 8px 16px;
    background: var(--gray-800);
    border-radius: var(--radius-md) var(--radius-md) 0 0;
    margin-bottom: -4px;
    font-size: 0.6875rem;
    color: var(--gray-400);
    text-transform: uppercase;
    letter-spacing: 0.06em;
}

.copy-btn {
    font-family: var(--font-mono);
    font-size: 0.6875rem;
    color: var(--gray-400);
    display: flex;
    align-items: center;
    gap: 4px;
    padding: 2px 6px;
    border-radius: 4px;
    transition: all var(--dur-fast) ease;
}

.copy-btn:hover {
    color: var(--white);
    background: rgba(255,255,255,0.1);
}


/* ============================================================
   STOP BUTTON
   ============================================================ */
.stop-btn {
    display: none;
    align-items: center;
    gap: 6px;
    padding: 8px 16px;
    border: 1px solid var(--border);
    border-radius: var(--radius-pill);
    font-size: 0.75rem;
    font-weight: 500;
    color: var(--text);
    background: var(--white);
    margin: 0 auto 12px;
    pointer-events: all;
    transition: all var(--dur-fast) ease;
}

.stop-btn.is-visible {
    display: flex;
}

.stop-btn:hover {
    background: var(--gray-100);
    border-color: var(--gray-400);
}

.stop-btn__icon {
    width: 12px;
    height: 12px;
    background: var(--gray-900);
    border-radius: 2px;
}


/* ============================================================
   RESPONSIVE
   ============================================================ */
@media (max-width: 768px) {
    .sidebar {
        position: fixed;
        left: 0;
        top: 0;
        transform: translateX(-100%);
    }

    .sidebar.is-open {
        transform: translateX(0);
    }

    .sidebar-toggle {
        display: grid;
    }

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

    .input-area {
        padding: 0 12px 12px;
    }

    .chat__messages {
        padding: 24px 16px;
    }

    .welcome {
        padding: 40px 16px 140px;
    }
}

@media (max-width: 480px) {
    .welcome__title {
        font-size: 1.5rem;
    }

    .prompt-chip {
        font-size: 0.75rem;
        padding: 12px 14px;
    }
}