:root {
    --bg: #121417;
    --bg-elevated: #1a1e24;
    --bg-panel: rgba(28, 33, 41, 0.92);
    --border: rgba(255, 255, 255, 0.08);
    --border-strong: rgba(255, 255, 255, 0.16);
    --text: #ecf1f8;
    --muted: #94a2b8;
    --accent: #6ea8fe;
    --accent-2: #67d5c4;
    --shadow: 0 20px 40px rgba(0, 0, 0, 0.28);
    --radius: 1.1rem;
}

html, body {
    min-height: 100%;
    overscroll-behavior: none;
}

body.theme-charcoal {
    font-family: "Manrope", sans-serif;
    color: var(--text);
    background:
        radial-gradient(circle at top left, rgba(94, 122, 255, 0.18), transparent 24%),
        radial-gradient(circle at top right, rgba(70, 196, 175, 0.14), transparent 24%),
        linear-gradient(180deg, #151920 0%, #111317 100%);
}

.guest-body { display: grid; place-items: center; padding: 2rem; }
.guest-shell { width: min(100%, 980px); }

.login-panel,
.panel-card,
.modal-content {
    background: var(--bg-panel);
    border: 1px solid var(--border);
    border-radius: calc(var(--radius) + 0.2rem);
    box-shadow: var(--shadow);
    backdrop-filter: blur(18px);
}

.login-panel { max-width: 560px; padding: 2rem; }
.login-panel h1 { font-size: clamp(2.1rem, 4vw, 3.4rem); font-weight: 800; margin-bottom: 0.75rem; }
.lead, .section-label, .message-time, .chat-item small, .message-card-footer, .model-option small, dt { color: var(--muted); }
.eyebrow { text-transform: uppercase; font-size: 0.75rem; letter-spacing: 0.12em; color: var(--accent-2); margin-bottom: 0.75rem; }
.feature-list { padding-left: 1.1rem; margin-bottom: 1.5rem; }

.workbench {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
    overflow: hidden;
}
.topbar { border-bottom: 1px solid var(--border); background: rgba(14, 17, 22, 0.72); backdrop-filter: blur(16px); }
.workspace { display: grid; grid-template-columns: 320px minmax(0, 1fr); min-height: calc(100vh - 72px); }
.workbench-sidebar { background: rgba(18, 21, 26, 0.92); border-right: 1px solid var(--border); }
.sidebar-section { margin-bottom: 1.25rem; }
.section-label { font-size: 0.78rem; text-transform: uppercase; letter-spacing: 0.08em; margin-bottom: 0.5rem; }
.chat-list { display: grid; gap: 0.45rem; }

.chat-item {
    display: flex;
    justify-content: space-between;
    gap: 0.75rem;
    color: var(--text);
    text-decoration: none;
    background: rgba(255, 255, 255, 0.03);
    border: 1px solid transparent;
    border-radius: 0.9rem;
    padding: 0.75rem 0.85rem;
}

.chat-item:hover,
.chat-item.active {
    border-color: rgba(110, 168, 254, 0.32);
    background: rgba(110, 168, 254, 0.08);
}

.conversation-shell {
    display: grid;
    grid-template-rows: auto 1fr auto;
    min-width: 0;
    min-height: 0;
    overflow: hidden;
}
.conversation-header { display: flex; justify-content: space-between; gap: 1rem; align-items: start; padding: 1.25rem 1.5rem 0.75rem; }
.conversation-title { font-size: 1.65rem; font-weight: 800; }
.conversation-actions, .composer-toolbar, .composer-actions, .preset-card-actions, .message-tools { display: flex; flex-wrap: wrap; gap: 0.5rem; }

.message-layout {
    display: grid;
    grid-template-columns: minmax(0, 1fr);
    gap: 1rem;
    min-height: 0;
    padding: 0.5rem 1.5rem 1rem;
    overflow: hidden;
}
.message-layout.split { grid-template-columns: minmax(0, 1.55fr) minmax(300px, 0.9fr); }
.message-column {
    display: grid;
    align-content: start;
    gap: 1rem;
    min-height: 0;
    overflow-y: auto;
    overscroll-behavior: contain;
    -webkit-overflow-scrolling: touch;
    padding-right: 0.25rem;
}
.raw-column {
    display: none;
    min-height: 0;
    overflow: hidden;
}

.raw-column .panel-card {
    min-height: 0;
    height: 100%;
    overflow: auto;
    overscroll-behavior: contain;
}
.message-layout.split .raw-column { display: block; }

.message-card {
    background: linear-gradient(180deg, rgba(31, 36, 44, 0.95), rgba(22, 26, 33, 0.96));
    border: 1px solid var(--border);
    border-radius: var(--radius);
    box-shadow: var(--shadow);
    overflow: hidden;
}

.message-card.role-user { border-color: rgba(103, 213, 196, 0.18); }
.message-card-header, .message-card-footer { display: flex; justify-content: space-between; gap: 0.75rem; padding: 0.8rem 1rem; border-bottom: 1px solid var(--border); }
.message-card-footer { border-bottom: 0; border-top: 1px solid var(--border); font-size: 0.78rem; }
.message-card-body { padding: 1rem; line-height: 1.7; }
.markdown-body a { color: #9cc4ff; }

.markdown-body pre,
.raw-pane {
    background: rgba(10, 13, 18, 0.95);
    border: 1px solid var(--border-strong);
    border-radius: 0.95rem;
    padding: 1rem;
    overflow: auto;
    font-family: "IBM Plex Mono", monospace;
    font-size: 0.92rem;
}

.code-block { position: relative; }
.code-copy { position: absolute; top: 0.75rem; right: 0.75rem; z-index: 2; }
.markdown-body table { width: 100%; border-collapse: collapse; margin: 1rem 0; }
.markdown-body th, .markdown-body td { padding: 0.65rem 0.75rem; border: 1px solid var(--border-strong); }

.composer-shell { padding: 0 1.5rem 1.5rem; }
.composer-box {
    display: flex;
    gap: 0.75rem;
    align-items: end;
    background: rgba(19, 23, 29, 0.95);
    border: 1px solid var(--border);
    border-radius: 1.1rem;
    padding: 0.85rem;
    box-shadow: var(--shadow);
}

.composer-input {
    resize: none;
    min-height: 54px;
    max-height: 220px;
    background: transparent;
    color: var(--text);
    border: 0;
}

.composer-input:focus,
.form-control:focus,
.form-select:focus,
.btn:focus-visible { box-shadow: 0 0 0 0.2rem rgba(110, 168, 254, 0.24); }

.form-control,
.form-select,
.modal-content,
.dropdown-menu { background-color: var(--bg-elevated); color: var(--text); border-color: var(--border); }

.btn-primary {
    background: linear-gradient(135deg, #5f8cff, #62d2c2);
    border: 0;
    color: #08111d;
    font-weight: 800;
}

.btn-outline-light { border-color: var(--border-strong); }
.preset-grid { display: grid; grid-template-columns: repeat(auto-fit, minmax(220px, 1fr)); gap: 1rem; }
.preset-card { background: rgba(255, 255, 255, 0.03); border: 1px solid var(--border); border-radius: 1rem; padding: 1rem; }
.preset-card-header { display: flex; justify-content: space-between; gap: 0.75rem; align-items: start; margin-bottom: 0.6rem; }
.raw-pane { white-space: pre-wrap; }
.search-input::placeholder, .composer-input::placeholder { color: #8291a7; }
.toast-container { z-index: 1090; }

@media (max-width: 991.98px) {
    .workspace { grid-template-columns: minmax(0, 1fr); }
    .conversation-header, .message-layout, .composer-shell { padding-left: 1rem; padding-right: 1rem; }
}

@media (prefers-reduced-motion: reduce) {
    * { scroll-behaviour: auto !important; transition: none !important; animation: none !important; }
}