@import url('https://fonts.googleapis.com/css2?family=Inter:wght@400;500;600;700&display=swap');

:root {
    --font: 'Inter', -apple-system, BlinkMacSystemFont, sans-serif;
    --radius: 14px;
    --radius-sm: 8px;
    --radius-pill: 100px;
    --transition: 0.3s cubic-bezier(0.4, 0, 0.2, 1);
    --max-w: 480px;
}

[data-theme="dark"] {
    --bg: #0d0d11;
    --bg-card: #161620;
    --bg-card-hover: #1c1c2a;
    --bg-input: #121218;
    --border: rgba(255, 255, 255, 0.06);
    --border-focus: rgba(120, 110, 220, 0.45);
    --text-1: #ededf0;
    --text-2: #7e7e96;
    --text-3: #4e4e64;
    --accent: #786edc;
    --accent-hover: #8b82e8;
    --accent-subtle: rgba(120, 110, 220, 0.12);
    --accent-glow: rgba(120, 110, 220, 0.25);
    --danger: #e05572;
    --danger-subtle: rgba(224, 85, 114, 0.1);
    --danger-border: rgba(224, 85, 114, 0.18);
    --success: #3dd68c;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.5);
    --overlay: rgba(10, 10, 14, 0.92);
}

[data-theme="light"] {
    --bg: #f4f4f6;
    --bg-card: #ffffff;
    --bg-card-hover: #f0f0f4;
    --bg-input: #eeeef2;
    --border: rgba(0, 0, 0, 0.06);
    --border-focus: rgba(100, 88, 200, 0.35);
    --text-1: #1a1a2e;
    --text-2: #6e6e84;
    --text-3: #a0a0b4;
    --accent: #6458c8;
    --accent-hover: #5648b8;
    --accent-subtle: rgba(100, 88, 200, 0.08);
    --accent-glow: rgba(100, 88, 200, 0.18);
    --danger: #d04060;
    --danger-subtle: rgba(208, 64, 96, 0.06);
    --danger-border: rgba(208, 64, 96, 0.12);
    --success: #28b870;
    --shadow: 0 4px 20px rgba(0, 0, 0, 0.06);
    --overlay: rgba(244, 244, 246, 0.94);
}

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

body {
    font-family: var(--font);
    background: var(--bg);
    color: var(--text-1);
    min-height: 100dvh;
    display: flex;
    justify-content: center;
    transition: background var(--transition), color var(--transition);
    -webkit-font-smoothing: antialiased;
    overflow-x: hidden;
}

.app-container {
    width: 100%;
    max-width: var(--max-w);
    min-height: 100dvh;
    padding: 1.5rem 1.25rem 2rem;
    display: flex;
    flex-direction: column;
    gap: 1.25rem;
}

.header {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.6rem;
}

.header-top {
    width: 100%;
    display: flex;
    justify-content: space-between;
    align-items: flex-start;
}

.header h1 {
    font-size: 1.35rem;
    font-weight: 700;
    letter-spacing: -0.4px;
    color: var(--text-1);
    transition: color var(--transition);
}

.header-subtitle {
    color: var(--text-2);
    font-size: 0.75rem;
    display: flex;
    align-items: center;
    gap: 0.35rem;
    margin-top: 0.15rem;
    transition: color var(--transition);
}

.status-indicator {
    width: 6px;
    height: 6px;
    border-radius: 50%;
    background: var(--danger);
    transition: all var(--transition);
    flex-shrink: 0;
}

.status-indicator.ready {
    background: var(--success);
    box-shadow: 0 0 6px rgba(61, 214, 140, 0.4);
}

.theme-toggle {
    width: 34px;
    height: 34px;
    border-radius: var(--radius-sm);
    border: 1px solid var(--border);
    background: var(--bg-card);
    color: var(--text-2);
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: all var(--transition);
    flex-shrink: 0;
}

.theme-toggle:hover {
    color: var(--text-1);
    border-color: var(--border-focus);
    background: var(--bg-card-hover);
}

[data-theme="dark"] .icon-moon { display: none; }
[data-theme="light"] .icon-sun { display: none; }

.room-info {
    display: flex;
    align-items: center;
    gap: 0.6rem;
    background: var(--bg-card);
    padding: 0.4rem 0.85rem;
    border-radius: var(--radius-pill);
    border: 1px solid var(--border);
    transition: all var(--transition);
}

.room-info span {
    color: var(--text-2);
    font-size: 0.78rem;
}

.room-info strong {
    color: var(--accent);
    font-size: 0.9rem;
    letter-spacing: 2px;
    font-weight: 700;
}

.leave-btn {
    background: var(--danger-subtle);
    color: var(--danger);
    border: 1px solid var(--danger-border);
    padding: 0.2rem 0.6rem;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 0.7rem;
    font-weight: 600;
    font-family: var(--font);
    transition: all var(--transition);
}

.leave-btn:hover {
    background: var(--danger);
    color: #fff;
}

.mode-toggle {
    display: flex;
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius-pill);
    padding: 3px;
    transition: all var(--transition);
}

.mode-toggle-btn {
    padding: 0.4rem 1.1rem;
    border-radius: var(--radius-pill);
    border: none;
    background: transparent;
    color: var(--text-3);
    font-family: var(--font);
    font-size: 0.8rem;
    font-weight: 600;
    cursor: pointer;
    transition: all var(--transition);
}

.mode-toggle-btn.active {
    background: var(--accent);
    color: #fff;
    box-shadow: 0 2px 8px var(--accent-glow);
}

.mode-toggle-btn:not(.active):hover {
    color: var(--text-1);
    background: var(--accent-subtle);
}

.main-content {
    flex: 1;
    display: flex;
    flex-direction: column;
    gap: 0.75rem;
}

.image-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    min-height: 300px;
    position: relative;
    overflow: hidden;
    transition: all var(--transition);
    box-shadow: var(--shadow);
}

.upload-prompt {
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.75rem;
    padding: 2.5rem 2rem;
    text-align: center;
}

.upload-icon {
    color: var(--text-3);
    opacity: 0.6;
}

.upload-btn {
    background: var(--accent);
    color: #fff;
    padding: 0.65rem 1.5rem;
    border-radius: var(--radius-pill);
    cursor: pointer;
    font-weight: 600;
    font-size: 0.85rem;
    font-family: var(--font);
    transition: all var(--transition);
    border: none;
    box-shadow: 0 3px 12px var(--accent-glow);
}

.upload-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
    box-shadow: 0 5px 16px var(--accent-glow);
}

.upload-btn:active { transform: translateY(0); }

.instruction-text {
    color: var(--text-3);
    font-size: 0.75rem;
}

.drop-zone {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 0.6rem;
    padding: 3rem 2rem;
    text-align: center;
    width: calc(100% - 2rem);
    height: calc(100% - 2rem);
    min-height: 280px;
    border: 2px dashed var(--border);
    border-radius: var(--radius);
    margin: 1rem;
    transition: all var(--transition);
}

.drop-zone.drag-over {
    border-color: var(--accent);
    background: var(--accent-subtle);
}

.drop-zone-icon {
    color: var(--text-3);
    opacity: 0.4;
    transition: all var(--transition);
}

.drop-zone.drag-over .drop-zone-icon {
    opacity: 0.8;
    color: var(--accent);
    transform: scale(1.08);
}

.drop-zone-text {
    font-size: 1rem;
    font-weight: 600;
    color: var(--text-1);
}

.drop-zone-subtext {
    font-size: 0.75rem;
    color: var(--text-3);
}

.loading-overlay {
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    gap: 1rem;
    padding: 3rem 2rem;
    text-align: center;
    width: calc(100% - 2rem);
    height: calc(100% - 2rem);
    min-height: 280px;
}

.spinner {
    width: 36px;
    height: 36px;
    border: 3px solid var(--border);
    border-top-color: var(--accent);
    border-radius: 50%;
    animation: spin 1s linear infinite;
}

.loading-text {
    font-size: 0.9rem;
    font-weight: 500;
    color: var(--text-2);
    animation: pulseText 1.5s ease-in-out infinite;
}

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

@keyframes pulseText {
    0%, 100% { opacity: 0.5; }
    50% { opacity: 1; }
}

#imageContainer {
    width: 100%;
    display: flex;
    flex-direction: column;
    align-items: center;
    gap: 0.85rem;
    padding: 1.25rem;
}

#sharedImage {
    max-width: 100%;
    max-height: 50vh;
    border-radius: var(--radius-sm);
    box-shadow: var(--shadow);
    object-fit: contain;
    transform-origin: center;
}

.download-btn,
.receive-btn {
    background: var(--accent);
    color: #fff;
    padding: 0.55rem 1.25rem;
    border-radius: var(--radius-pill);
    border: none;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.8rem;
    font-family: var(--font);
    transition: all var(--transition);
    box-shadow: 0 3px 12px var(--accent-glow);
    display: flex;
    align-items: center;
    gap: 0.4rem;
}

.download-btn:hover,
.receive-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

@keyframes dropItem {
    0% { transform: scale(0.85) translateY(16px); opacity: 0; }
    60% { transform: scale(1.01) translateY(-2px); opacity: 1; }
    100% { transform: scale(1) translateY(0); opacity: 1; }
}

@keyframes grabItem {
    0% { transform: scale(1); opacity: 1; }
    100% { transform: scale(0.88); opacity: 0; }
}

@keyframes fadeVanish {
    0% { opacity: 1; transform: scale(1); }
    100% { opacity: 0; transform: scale(0.96); }
}

.anim-drop { animation: dropItem 0.45s cubic-bezier(0.2, 0.8, 0.2, 1) forwards !important; }
.anim-grab { animation: grabItem 0.45s cubic-bezier(0.4, 0, 0.2, 1) forwards !important; }
.anim-fade-vanish { animation: fadeVanish 0.7s cubic-bezier(0.4, 0, 0.2, 1) forwards !important; }

.room-selection-overlay {
    position: fixed;
    inset: 0;
    background: var(--overlay);
    backdrop-filter: blur(16px);
    -webkit-backdrop-filter: blur(16px);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
    padding: 1.25rem;
    transition: background var(--transition);
}

.room-card {
    background: var(--bg-card);
    border: 1px solid var(--border);
    border-radius: var(--radius);
    padding: 2.25rem 1.75rem;
    text-align: center;
    max-width: 360px;
    width: 100%;
    box-shadow: var(--shadow);
    transition: all var(--transition);
}

.room-card h2 {
    font-size: 1.4rem;
    font-weight: 700;
    margin-bottom: 0.3rem;
    color: var(--text-1);
    letter-spacing: -0.4px;
}

.room-card > p {
    color: var(--text-2);
    margin-bottom: 1.75rem;
    font-size: 0.8rem;
}

.room-actions {
    display: flex;
    flex-direction: column;
    gap: 1rem;
}

.room-actions .action-btn {
    width: 100%;
    background: var(--accent);
    color: #fff;
    padding: 0.65rem 1.25rem;
    border-radius: var(--radius-pill);
    border: none;
    cursor: pointer;
    font-weight: 600;
    font-size: 0.85rem;
    font-family: var(--font);
    transition: all var(--transition);
    box-shadow: 0 3px 12px var(--accent-glow);
}

.room-actions .action-btn:hover {
    background: var(--accent-hover);
    transform: translateY(-1px);
}

.divider {
    position: relative;
    text-align: center;
}

.divider::before {
    content: '';
    position: absolute;
    left: 0;
    top: 50%;
    width: 100%;
    height: 1px;
    background: var(--border);
}

.divider span {
    background: var(--bg-card);
    padding: 0 0.6rem;
    color: var(--text-3);
    font-size: 0.72rem;
    position: relative;
    font-weight: 500;
    transition: background var(--transition), color var(--transition);
}

.join-form {
    display: flex;
    gap: 0.4rem;
}

#roomCodeInput {
    flex: 1;
    background: var(--bg-input);
    border: 1px solid var(--border);
    border-radius: var(--radius-pill);
    padding: 0.6rem 1rem;
    color: var(--text-1);
    font-size: 0.95rem;
    text-align: center;
    outline: none;
    letter-spacing: 3px;
    font-family: var(--font);
    font-weight: 600;
    transition: all var(--transition);
}

#roomCodeInput:focus {
    border-color: var(--border-focus);
    box-shadow: 0 0 0 3px var(--accent-subtle);
}

#roomCodeInput::placeholder {
    letter-spacing: 0;
    font-weight: 400;
    color: var(--text-3);
}

.error-text {
    color: var(--danger) !important;
    margin-top: 0.75rem !important;
    margin-bottom: 0 !important;
    font-size: 0.78rem;
    min-height: 1.2em;
}

.status-bar {
    display: flex;
    gap: 0.5rem;
    justify-content: center;
}

.status-pill {
    display: flex;
    align-items: center;
    gap: 0.35rem;
    padding: 0.3rem 0.7rem;
    border-radius: var(--radius-pill);
    background: var(--bg-card);
    border: 1px solid var(--border);
    font-size: 0.7rem;
    font-weight: 500;
    color: var(--text-2);
    transition: all var(--transition);
}

.status-pill svg {
    flex-shrink: 0;
}

.status-pill-dot {
    width: 5px;
    height: 5px;
    border-radius: 50%;
    background: var(--text-3);
    transition: all var(--transition);
    flex-shrink: 0;
}

.status-pill-dot.active {
    background: var(--accent);
    box-shadow: 0 0 5px var(--accent-glow);
}

@media (max-width: 480px) {
    .app-container {
        padding: 1rem 1rem 1.5rem;
        gap: 1rem;
    }

    .header h1 { font-size: 1.2rem; }

    .room-card { padding: 1.75rem 1.5rem; }
    .room-card h2 { font-size: 1.2rem; }

    .image-card { min-height: 260px; }
    .drop-zone { min-height: 240px; padding: 2rem 1.5rem; }

    .mode-toggle-btn { padding: 0.35rem 0.9rem; font-size: 0.75rem; }
}

@media (min-width: 769px) {
    body { align-items: center; }
    .app-container { min-height: auto; padding: 2rem; }
}