:root {
    --primary-color: #3b82f6;
    --success-color: #22c55e;
    --danger-color: #ef4444;
    --bg-color: #f8f9fa;
    --text-color: #1f2937;
    --white: #ffffff;
    --gray: #9ca3af;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    -webkit-tap-highlight-color: transparent;
}

body {
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, Helvetica, Arial, sans-serif;
    font-size: 20px;
    background-color: var(--bg-color);
    color: var(--text-color);
    line-height: 1.5;
    overflow: hidden;
    user-select: none; /* Metin seçmeyi engelle (yaşlı dostu) */
}

/* Layout */
.screen {
    position: fixed;
    top: 0;
    left: 0;
    width: 100vw;
    height: 100vh;
    padding: 20px;
    background: var(--bg-color);
    z-index: 10;
    overflow-y: auto;
}

.content-center {
    display: flex;
    flex-direction: column;
    justify-content: center;
    align-items: center;
    height: 100%;
    text-align: center;
}

header {
    margin-bottom: 24px;
    padding: 10px 0;
    border-bottom: 2px solid #e5e7eb;
}

/* Typography */
h1 { font-size: 32px; margin-bottom: 16px; }
h2 { font-size: 28px; margin-bottom: 12px; }
p { margin-bottom: 20px; }

/* Buttons */
button {
    font-family: inherit;
    font-weight: bold;
    font-size: 22px;
    border: none;
    border-radius: 16px;
    cursor: pointer;
    min-height: 80px;
    padding: 12px 24px;
    transition: transform 0.1s;
    width: 100%;
    margin-top: 10px;
}

button:active {
    transform: scale(0.98);
}

.btn-primary { background-color: var(--primary-color); color: var(--white); }
.btn-success { background-color: var(--success-color); color: var(--white); }
.btn-danger { background-color: var(--danger-color); color: var(--white); }

/* Forms */
input[type="text"] {
    width: 100%;
    min-height: 60px;
    font-size: 22px;
    padding: 16px;
    border: 2px solid var(--gray);
    border-radius: 12px;
    margin-bottom: 20px;
}

/* Presence List */
.person-card {
    background: var(--white);
    padding: 24px;
    border-radius: 16px;
    box-shadow: 0 4px 6px -1px rgba(0, 0, 0, 0.1);
    margin-bottom: 16px;
    display: flex;
    flex-direction: column;
}

.person-name {
    font-size: 26px;
    font-weight: bold;
    margin-bottom: 12px;
}

.empty-state {
    color: var(--gray);
    text-align: center;
    margin-top: 40px;
}

/* Call Screens */
.dark-bg {
    background-color: #1e293b;
    color: var(--white);
}

.call-type {
    color: var(--gray);
    text-transform: uppercase;
    letter-spacing: 1px;
    margin-bottom: 8px;
}

.call-actions {
    display: flex;
    gap: 16px;
    width: 100%;
    margin-top: 30px;
}

#call-container {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: #000;
}

/* Overlay */
.overlay {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.8);
    display: flex;
    justify-content: center;
    align-items: center;
    z-index: 100;
}

.overlay-content {
    background: var(--white);
    padding: 30px;
    border-radius: 20px;
    max-width: 80%;
    text-align: center;
}

/* Spinner */
.spinner {
    border: 6px solid #f3f3f3;
    border-top: 6px solid var(--primary-color);
    border-radius: 50%;
    width: 60px;
    height: 60px;
    animation: spin 1s linear infinite;
    margin-bottom: 24px;
}

@keyframes spin {
    0% { transform: rotate(0deg); }
    100% { transform: rotate(360deg); }
}