:root {
    --bg-color: #f0f7ff;
    --text-color: #222;
    --accent-color: #4285f4;
    --border-color: #ccc;
    --message-sent: #1a73e8;
    --message-received: #333;
    --error-color: #d93025;
    --system-messages-bg: #f8f8f8;
    --video-placeholder-bg: #eee;
    /* --system-color: #aaa; */
    --device-container-bg: #f5f5f5;
    --device-select-text-color: #222;
    --device-select-bg: #fff;
    --device-select-border: #ccc;
    --button-hover: #3367d6;
}

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

html, body {
    margin: 0;
    padding: 0;
    height: 100%; 
}

body {
    font-family: 'Segoe UI', sans-serif;
    background-color: var(--bg-color);
    color: var(--text-color);
    height: 100vh; 
    display: grid; 
    overflow: hidden; 
    grid-template-columns: 2fr 1fr;
    gap: 20px;
    transition: background-color 0.5s ease, color 0.5s ease;
}

body.dark-mode {
    --bg-color: #121212;
    --text-color: #e0e0e0;
    --accent-color: #8ab4f8;
    --border-color: #444;
    --message-sent: #8ab4f8;
    --message-received: #cfcfcf;
    --error-color: #ff6e6e;
    --system-messages-bg: #1a1a1a; 
    --video-placeholder-bg: #222; 
    --device-container-bg: #1a1a1a; 
    --device-select-text-color: #e0e0e0; 
    --device-select-bg: #2c2c2c; 
    --device-select-border: #444;
    --button: #2c2c2c;
    --button-hover: #3a3a3a;
    background-color: var(--bg-color);
    color: var(--text-color);
}

body.dark-mode #messages {
    background-color: #1f1f1f;
    border-color: var(--border-color);
}

body.dark-mode input[type="text"],
body.dark-mode button {
    background-color: var(--button);
    color: var(--text-color);
    border: 1px solid var(--border-color);
}

body.dark-mode button:hover {
    background-color: var(--button-hover);
}

body.dark-mode .right-area h3 { 
    color: var(--accent-color); 

}

body.dark-mode #systemMessagesContent {
    color: #ccc; 
}

body.dark-mode #systemMessagesContent p {
    border-bottom-color: #444; 
}

.hidden {
    display: none;
}

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

.left-area {
    grid-column: 1;
    margin-left: 20px;
    display: flex; 
    flex-direction: column; 
    height: 100%; 
    overflow: hidden; 
}

.right-area {
    grid-column: 2;
    margin-right: 20px;
    display: flex; 
    flex-direction: column; 
    height: 100%; 
    overflow: hidden; 
}

.video-section {
    display: grid;
    gap: 20px;
    grid-template-columns: 1fr 2fr;
    margin-bottom: 20px;
    margin-top: 20px;
    flex-shrink: 0; 
}

.video-column-l, .video-column-r {
    display: flex; 
    flex-direction: column; 
    justify-content: flex-end; 
}

.video-column-l {
    grid-column: 1;
}

.video-column-r {
    grid-column: 2;
}

#localVideo, #remoteVideo {
    width: 100%;
    aspect-ratio: 16 / 9;
    border: 1px solid var(--border-color);
    background: var(--video-placeholder-bg); 
    border-radius: 5px;
    transition: background 0.5s ease, border-color 0.5s ease;
}

h1, h2, h3 {
    color: var(--accent-color);
    transition: color 0.5s ease;
}

#systemMessagesContent {
    overflow-y: auto; 
    font-size: 0.9em;
    color: #555;
    border: 1px solid var(--border-color); 
    flex-grow: 1; 
    background-color: var(--system-messages-bg); 
    padding: 5px;
    border-radius: 8px;
    margin-bottom:20px;
    min-height: 0; 
    transition: background-color 0.5s ease, color 0.5s ease, border-color 0.5s ease;
}

#systemMessagesContent p {
    margin: 3px 0;
    padding: 2px 0;
    border-bottom: 1px dotted #eee;
}

#systemMessagesContent p:last-child {
    border-bottom: none;
}

#messages {
    border: 1px solid var(--border-color); 
    background: #fff;
    padding: 0.5em;
    overflow-y: auto; 
    border-radius: 8px;
    box-shadow: 0 2px 5px rgba(0,0,0,0.05);
    margin-bottom: 0.5rem;
    flex-grow: 1; 
    min-height: 0; 
    word-wrap: break-word; 
    transition: background-color 0.5s ease, border-color 0.5s ease;
}

#messages p.sent {
    color: var(--message-sent);
}

#messages p.received {
    color: var(--message-received);
}

#messages p.error {
    color: var(--error-color);
}

.sent, .received, .error {
    transition: color 0.5s ease; 
}

input[type="text"],
button {
    padding: 10px;
    border-radius: 4px;
    border: 1px solid var(--border-color); 
    margin-top: 10px; 
    flex-shrink: 0; 
    transition: background-color 0.5s ease, color 0.5s ease, border-color 0.5s ease;
}

button {
    background-color: var(--accent-color);
    color: white;
    cursor: pointer;
}

button:hover {
    background-color: var(--button-hover); 
}

.sent { color: var(--message-sent); }
.received { color: var(--message-received); }
/* .system { color: var(--system-color); } */
.error { color: var(--error-color); }

.message-input-wrapper {
    display: flex;
    gap: 0.5rem;
    margin-bottom: 20px;
    flex-shrink: 0; 
}

#messageInput {
    flex: 0 1 93%; 
    padding: 5px;
}

#sendMessageButton {
    flex: 0 1 7%; 
}

#calleeStatus {
    border-radius: 5px;
    flex-shrink: 0; 
}

#incomingCallDiv {
    flex-shrink: 0; 
}

#calleeStatus, #incomingCallDiv {
    transition: background-color 0.5s ease, color 0.5s ease, border-color 0.5s ease;
}

#toggleDevices {
    flex-shrink: 0; 
}

.device-select-wrapper {
    display: flex;
    flex-direction: column;
    gap: 1rem;
    width: 65%; 
    flex-shrink: 0; 
	margin: 0 auto; 
	padding: 20px;
}

.device-select-wrapper label {
    color: var(--text-color); 
    font-weight: bold;
    margin-bottom: 5px;
}

.device-select-wrapper select {
    padding: 8px;
    border-radius: 4px;
    border: 1px solid var(--device-select-border); 
    background-color: var(--device-select-bg); 
    color: var(--device-select-text-color); 
    width: 100%;
}

#logoimg {
    max-width: 100%;
    height: auto;
    object-fit: contain;
    display: block;
    margin: 0 auto 20px 0;
}

#deviceContainer {
    overflow: hidden;
    transition: height 0.4s ease;
    height: 0; 
	background: var(--device-container-bg); 
    flex-shrink: 0; 
    border-radius: 8px; 
    transition: height 0.4s ease, background 0.5s ease, border-color 0.5s ease;
}

#imageContainer {
    position: relative;
    height: 200px;
    overflow: hidden;
    display: flex;
    justify-content: center;
    align-items: center;
    /* mask-image: radial-gradient(ellipse at center, rgba(0,0,0,1) 80%, rgba(0,0,0,0) 100%); */
    mask-image: linear-gradient(to top, transparent 0px, black 20px, black calc(100% - 20px), transparent 100%);
    /* -webkit-mask-image: radial-gradient(ellipse at center, rgba(0,0,0,1) 80%, rgba(0,0,0,0) 100%); */
    border-radius: 12px;
}

.image-fade {
    position: absolute;
    width: 100%;
    /* height: 100%; */
    max-width: none;
    max-height: none;
    opacity: 0;
    transition: all 2s ease;
    /* object-fit: cover; */
    border-radius: 12px;
}

.zoom-in    { transform: scale(1.4); }
.zoom-out   { transform: scale(0.6); }
.rotate     { transform: rotate(10deg); }
.skew       { transform: skew(15deg, 5deg); }
.flip       { transform: rotateY(180deg); }
.slide-left { transform: translateX(-100%); }
.slide-right{ transform: translateX(100%); }
.slide-up   { transform: translateY(-100%); }
.slide-down { transform: translateY(100%); }
.blur       { filter: blur(5px); }
.grayscale  { filter: grayscale(100%); }
.hue        { filter: hue-rotate(90deg); }
.sepia      { filter: sepia(100%); }
.invert     { filter: invert(100%); }

.visible {
    opacity: 1;
    transform: none !important;
    filter: none !important;
}

.button-grid {
    display: flex;
    justify-content: space-evenly;
    gap: 1rem;
}

.grid-button {
    flex: 1 1 0;
    min-width: 0;
    padding: 1em 0;
    margin: 0;
    border: none;
    background: #eee;
    cursor: pointer;
}

#muteSoundToggle {
    background-color: #f0ad4e; 
    color: white;
    border: none;
    padding: 6px 12px;
    border-radius: 4px;
    cursor: pointer;
}

#muteSoundToggle.muted {
    background-color: #d9534f; 
}

#muteSoundToggle:hover {
    opacity: 0.9;
}

body.dark-mode #muteSoundToggle {
    background-color: #8c4e00;
}

body.dark-mode #muteSoundToggle.muted {
    background-color: #a00;
}