:root {
    --background: #f3f4f6;
    --surface: #ffffff;
    --surface_secondary: #f9fafb;
    --border: #e5e7eb;
    --border_strong: #d1d5db;
    --text_primary: #111827;
    --text_secondary: #6b7280;
    --primary: #2563eb;
    --primary_hover: #1d4ed8;
    --success: #059669;
    --warning: #d97706;
    --danger: #dc2626;
    --danger_background: #fef2f2;
    --shadow: 0 18px 50px rgba(17, 24, 39, 0.08);
    --radius_large: 22px;
    --radius_medium: 14px;
    --radius_small: 10px;
}

* {
    box-sizing: border-box;
}

html {
    min-height: 100%;
    background: var(--background);
}

body {
    min-height: 100vh;
    margin: 0;
    color: var(--text_primary);
    background:
        radial-gradient(circle at top left, rgba(37, 99, 235, 0.08), transparent 34rem),
        var(--background);
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", sans-serif;
}

button,
input {
    font: inherit;
}

button {
    cursor: pointer;
}

button:disabled,
input:disabled {
    cursor: not-allowed;
    opacity: 0.55;
}

.page_shell {
    width: min(1180px, calc(100% - 32px));
    margin: 0 auto;
    padding: 42px 0 64px;
}

.app_header {
    display: flex;
    align-items: flex-start;
    justify-content: space-between;
    gap: 24px;
    margin-bottom: 28px;
}

.app_header h1 {
    margin: 3px 0 8px;
    font-size: clamp(2rem, 5vw, 3.4rem);
    letter-spacing: -0.055em;
}

.eyebrow,
.step_label {
    color: var(--primary);
    font-size: 0.74rem;
    font-weight: 800;
    letter-spacing: 0.14em;
}

.eyebrow {
    margin: 0;
}

.header_text {
    max-width: 660px;
    margin: 0;
    color: var(--text_secondary);
    font-size: 1rem;
    line-height: 1.65;
}

.connection_badge {
    display: inline-flex;
    align-items: center;
    gap: 9px;
    min-width: max-content;
    padding: 10px 14px;
    border: 1px solid var(--border);
    border-radius: 999px;
    background: rgba(255, 255, 255, 0.78);
    box-shadow: 0 8px 24px rgba(17, 24, 39, 0.05);
    color: var(--text_secondary);
    font-size: 0.88rem;
    font-weight: 700;
    backdrop-filter: blur(10px);
}

.status_dot {
    width: 9px;
    height: 9px;
    border-radius: 50%;
    background: var(--warning);
    box-shadow: 0 0 0 4px rgba(217, 119, 6, 0.12);
}

.connection_badge_connected .status_dot {
    background: var(--success);
    box-shadow: 0 0 0 4px rgba(5, 150, 105, 0.12);
}

.connection_badge_error .status_dot {
    background: var(--danger);
    box-shadow: 0 0 0 4px rgba(220, 38, 38, 0.12);
}

.connection_grid,
.activity_grid {
    display: grid;
    grid-template-columns: repeat(2, minmax(0, 1fr));
    gap: 20px;
}

.panel {
    border: 1px solid rgba(229, 231, 235, 0.92);
    border-radius: var(--radius_large);
    background: rgba(255, 255, 255, 0.94);
    box-shadow: var(--shadow);
    padding: 24px;
}

.panel_heading {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 18px;
    margin-bottom: 20px;
}

.panel_heading h2 {
    margin: 5px 0 0;
    font-size: 1.14rem;
    letter-spacing: -0.025em;
}

.room_code_box {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    padding: 16px 16px 16px 20px;
    border: 1px solid var(--border);
    border-radius: var(--radius_medium);
    background: var(--surface_secondary);
}

.room_code_primary {
    display: flex;
    align-items: center;
    gap: 16px;
    flex: 1;
    min-width: 0;
}

.room_code {
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: clamp(1.8rem, 5vw, 2.5rem);
    font-weight: 800;
    letter-spacing: 0.18em;
}

.qr_code_container {
    flex-shrink: 0;
    display: flex;
    align-items: center;
    justify-content: center;
    width: 100px;
    height: 100px;
    padding: 5px;
    border-radius: var(--radius_small);
    background: #ffffff;
    box-shadow: 0 1px 4px rgba(0, 0, 0, 0.08);
}

.qr_code_container img {
    display: block;
    width: 100%;
    height: auto;
    image-rendering: pixelated;
}

.helper_text {
    margin: 14px 0 0;
    color: var(--text_secondary);
    font-size: 0.88rem;
    line-height: 1.55;
}

.icon_button,
.text_button {
    border: 0;
    background: transparent;
    color: var(--primary);
    font-weight: 750;
}

.icon_button {
    padding: 10px 12px;
    border: 1px solid var(--border_strong);
    border-radius: var(--radius_small);
    background: var(--surface);
}

.join_form label {
    display: block;
    margin-bottom: 8px;
    color: var(--text_secondary);
    font-size: 0.86rem;
    font-weight: 650;
}

.input_group {
    display: flex;
    gap: 10px;
}

.input_group input {
    width: 100%;
    min-width: 0;
    padding: 14px 15px;
    border: 1px solid var(--border_strong);
    border-radius: var(--radius_small);
    outline: none;
    text-transform: uppercase;
    font-family: ui-monospace, SFMono-Regular, Menlo, Consolas, monospace;
    font-size: 1.05rem;
    font-weight: 750;
    letter-spacing: 0.12em;
    transition: border-color 160ms ease, box-shadow 160ms ease;
}

.input_group input:focus {
    border-color: var(--primary);
    box-shadow: 0 0 0 4px rgba(37, 99, 235, 0.12);
}

.primary_button,
.danger_button {
    border: 0;
    border-radius: var(--radius_small);
    padding: 13px 18px;
    color: #ffffff;
    font-weight: 760;
    transition: transform 150ms ease, background 150ms ease;
}

.primary_button {
    background: var(--primary);
}

.primary_button:hover:not(:disabled) {
    background: var(--primary_hover);
    transform: translateY(-1px);
}

.danger_button {
    background: var(--danger);
}

.danger_button:hover:not(:disabled) {
    transform: translateY(-1px);
}

.transfer_panel {
    margin-top: 20px;
    transition: opacity 180ms ease;
}

.transfer_panel.is_disabled {
    opacity: 0.66;
}

.transfer_heading {
    margin-bottom: 18px;
}

.drop_zone {
    display: flex;
    min-height: 190px;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 26px;
    border: 2px dashed var(--border_strong);
    border-radius: var(--radius_medium);
    background: var(--surface_secondary);
    color: var(--text_secondary);
    text-align: center;
    transition: border-color 160ms ease, background 160ms ease, transform 160ms ease;
}

.drop_zone:not(.is_disabled):hover,
.drop_zone.is_dragging {
    border-color: var(--primary);
    background: rgba(37, 99, 235, 0.055);
    transform: translateY(-1px);
}

.drop_zone input {
    display: none;
}

.drop_zone strong {
    color: var(--text_primary);
    font-size: 1rem;
}

.drop_zone span:last-child {
    font-size: 0.84rem;
}

.drop_icon {
    display: grid;
    width: 48px;
    height: 48px;
    place-items: center;
    border-radius: 14px;
    background: rgba(37, 99, 235, 0.1);
    color: var(--primary);
    font-size: 1.6rem;
    font-weight: 800;
}

.selected_files_container {
    margin-top: 22px;
}

.section_title_row {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 16px;
    margin-bottom: 10px;
}

.section_title_row h3 {
    margin: 0;
    font-size: 0.98rem;
}

.file_list {
    display: grid;
    gap: 9px;
    margin: 0;
    padding: 0;
    list-style: none;
}

.file_item,
.transfer_item,
.received_file_item {
    border: 1px solid var(--border);
    border-radius: var(--radius_small);
    background: var(--surface_secondary);
}

.file_item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
    padding: 12px 14px;
}

.file_item_name,
.transfer_name,
.received_file_name {
    min-width: 0;
    overflow: hidden;
    text-overflow: ellipsis;
    white-space: nowrap;
    font-weight: 720;
}

.file_item_size,
.transfer_meta,
.received_file_meta {
    color: var(--text_secondary);
    font-size: 0.8rem;
}

.send_button {
    width: 100%;
    margin-top: 14px;
}

.activity_grid {
    margin-top: 20px;
}

.empty_state {
    min-height: 82px;
    display: grid;
    place-items: center;
    color: var(--text_secondary);
    font-size: 0.9rem;
    text-align: center;
}

.transfer_items,
.received_file_items {
    display: grid;
    gap: 10px;
}

.transfer_item {
    padding: 13px 14px;
}

.transfer_top_row,
.received_file_item {
    display: flex;
    align-items: center;
    justify-content: space-between;
    gap: 14px;
}

.progress_track {
    height: 7px;
    margin-top: 11px;
    overflow: hidden;
    border-radius: 999px;
    background: #e5e7eb;
}

.progress_bar {
    width: 0;
    height: 100%;
    border-radius: inherit;
    background: var(--primary);
    transition: width 100ms linear;
}

.transfer_item.is_complete .progress_bar {
    background: var(--success);
}

.transfer_item.is_error .progress_bar {
    background: var(--danger);
}

.received_file_item {
    padding: 13px 14px;
}

.download_button {
    flex: 0 0 auto;
    padding: 9px 12px;
    border: 1px solid var(--border_strong);
    border-radius: 9px;
    background: var(--surface);
    color: var(--primary);
    font-weight: 730;
    text-decoration: none;
}

.toast {
    position: fixed;
    right: 24px;
    bottom: 24px;
    z-index: 10;
    max-width: min(390px, calc(100vw - 48px));
    padding: 13px 16px;
    border-radius: 12px;
    background: #111827;
    color: #ffffff;
    box-shadow: 0 16px 38px rgba(17, 24, 39, 0.25);
    font-size: 0.9rem;
    line-height: 1.45;
    opacity: 0;
    pointer-events: none;
    transform: translateY(12px);
    transition: opacity 180ms ease, transform 180ms ease;
}

.toast.is_visible {
    opacity: 1;
    transform: translateY(0);
}

.is_hidden {
    display: none !important;
}

@media (max-width: 820px) {
    .page_shell {
        width: min(100% - 22px, 680px);
        padding-top: 24px;
    }

    .app_header {
        flex-direction: column;
    }

    .connection_grid,
    .activity_grid {
        grid-template-columns: 1fr;
    }

    .connection_badge {
        align-self: flex-start;
    }
}

@media (max-width: 520px) {
    .panel {
        padding: 18px;
        border-radius: 17px;
    }

    .input_group {
        flex-direction: column;
    }

    .input_group .primary_button {
        width: 100%;
    }

    .transfer_heading {
        align-items: flex-start;
        flex-direction: column;
    }

    .danger_button {
        width: 100%;
    }

    .room_code_box {
        align-items: stretch;
        flex-direction: column;
        text-align: center;
    }

    .room_code_primary {
        justify-content: center;
        flex-wrap: wrap;
    }

    .qr_code_container {
        align-self: center;
    }

    .room_code {
        letter-spacing: 0.13em;
    }

    .toast {
        right: 14px;
        bottom: 14px;
        max-width: calc(100vw - 28px);
    }
}