* {
    margin: 0;
    padding: 0;
    box-sizing: border-box;
}
:root {
    --primary: #2563eb;
    --primary-dark: #1d4ed8;
    --success: #16a34a;
    --danger: #dc2626;
    --bg-dark: #1e293b;
    --bg-darker: #0f172a;
    --bg-light: #334155;
    --text-primary: #f8fafc;
    --text-secondary: #94a3b8;
    --border: #475569;
}
body {
    font-family: -apple-system, BlinkMacSystemFont, sans-serif;
    background: var(--bg-darker);
    color: var(--text-primary);
    height: 100vh;
    overflow: hidden;
}
.app-container {
    display: flex;
    flex-direction: column;
    height: 100vh;
}
.header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 12px 24px;
    background: var(--bg-dark);
    border-bottom: 1px solid var(--border);
}
.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}
.logo-icon { font-size: 24px; color: var(--primary); }
.logo-text { font-size: 20px; font-weight: 600; }
.header-right {
    display: flex;
    align-items: center;
    gap: 20px;
}
.user-display, .balance-display {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: var(--bg-light);
    border-radius: 8px;
    font-size: 14px;
}
.balance-display { color: var(--success); }
.btn-icon {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 18px;
    cursor: pointer;
    padding: 8px;
    border-radius: 8px;
}
.btn-icon:hover { background: var(--bg-light); color: var(--text-primary); }
.main-content {
    display: flex;
    flex: 1;
    overflow: hidden;
}
.side-panel {
    width: 280px;
    background: var(--bg-dark);
    border-right: 1px solid var(--border);
    display: flex;
    flex-direction: column;
}
.panel-tabs {
    display: flex;
    border-bottom: 1px solid var(--border);
}
.tab-btn {
    flex: 1;
    padding: 12px;
    background: none;
    border: none;
    color: var(--text-secondary);
    cursor: pointer;
}
.tab-btn.active {
    color: var(--primary);
    border-bottom: 2px solid var(--primary);
}
.tab-content {
    display: none;
    flex: 1;
    overflow-y: auto;
    padding: 12px;
}
.tab-content.active {
    display: flex;
    flex-direction: column;
}
.search-box {
    position: relative;
    margin-bottom: 12px;
}
.search-box i {
    position: absolute;
    left: 12px;
    top: 50%;
    transform: translateY(-50%);
    color: var(--text-secondary);
}
.search-box input {
    width: 100%;
    padding: 10px 12px 10px 36px;
    background: var(--bg-light);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    font-size: 14px;
}
.contacts-list, .history-list {
    flex: 1;
    overflow-y: auto;
}
.contact-item, .history-item {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 12px;
    border-radius: 8px;
    cursor: pointer;
}
.contact-item:hover, .history-item:hover { background: var(--bg-light); }
.contact-avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--primary);
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 600;
}
.contact-info { flex: 1; }
.contact-name { font-weight: 500; margin-bottom: 2px; }
.contact-number { font-size: 12px; color: var(--text-secondary); }
.btn-add {
    display: flex;
    align-items: center;
    justify-content: center;
    gap: 8px;
    padding: 12px;
    background: var(--primary);
    border: none;
    border-radius: 8px;
    color: white;
    font-weight: 500;
    cursor: pointer;
    margin-top: 12px;
}
.btn-add:hover { background: var(--primary-dark); }
.dialer-panel {
    flex: 1;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
    padding: 24px;
}
.call-status {
    text-align: center;
    margin-bottom: 24px;
}
.status-text {
    font-size: 16px;
    color: var(--text-secondary);
    margin-bottom: 8px;
}
.call-timer {
    font-size: 48px;
    font-weight: 300;
    font-variant-numeric: tabular-nums;
}
.number-input-container {
    display: flex;
    align-items: center;
    gap: 12px;
    margin-bottom: 24px;
}
.number-input {
    width: 300px;
    padding: 16px 20px;
    background: var(--bg-dark);
    border: 2px solid var(--border);
    border-radius: 12px;
    color: var(--text-primary);
    font-size: 24px;
    text-align: center;
    letter-spacing: 2px;
}
.number-input:focus { outline: none; border-color: var(--primary); }
.btn-backspace {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 20px;
    cursor: pointer;
    padding: 8px;
}
.dialpad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 12px;
    margin-bottom: 24px;
}
.dialpad-btn {
    width: 80px;
    height: 80px;
    border-radius: 50%;
    background: var(--bg-dark);
    border: 2px solid var(--border);
    color: var(--text-primary);
    font-size: 24px;
    cursor: pointer;
    display: flex;
    flex-direction: column;
    align-items: center;
    justify-content: center;
}
.dialpad-btn:hover { background: var(--bg-light); border-color: var(--primary); }
.dialpad-btn:active { transform: scale(0.95); }
.dialpad-btn .letters { font-size: 10px; color: var(--text-secondary); margin-top: 2px; }
.call-controls { display: flex; gap: 16px; }
.btn-call, .btn-hangup {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    border: none;
    font-size: 24px;
    cursor: pointer;
}
.btn-call { background: var(--success); color: white; }
.btn-call:hover { background: #15803d; }
.btn-hangup { background: var(--danger); color: white; }
.btn-hangup:hover { background: #b91c1c; }
.btn-control {
    width: 48px;
    height: 48px;
    border-radius: 50%;
    background: var(--bg-dark);
    border: 2px solid var(--border);
    color: var(--text-primary);
    font-size: 16px;
    cursor: pointer;
}
.btn-control:hover:not(:disabled) { background: var(--bg-light); border-color: var(--primary); }
.btn-control:disabled { opacity: 0.5; cursor: not-allowed; }
.dtmf-keypad {
    display: grid;
    grid-template-columns: repeat(3, 1fr);
    gap: 8px;
    margin-top: 16px;
    padding: 16px;
    background: var(--bg-dark);
    border-radius: 12px;
}
.dtmf-btn {
    width: 60px;
    height: 50px;
    border-radius: 8px;
    background: var(--bg-light);
    border: 1px solid var(--border);
    color: var(--text-primary);
    font-size: 18px;
    cursor: pointer;
}
.dtmf-btn:hover { background: var(--primary); }
.info-panel {
    width: 240px;
    background: var(--bg-dark);
    border-left: 1px solid var(--border);
    padding: 16px;
}
.info-section h3 {
    font-size: 14px;
    color: var(--text-secondary);
    margin-bottom: 16px;
}
.info-row {
    display: flex;
    justify-content: space-between;
    padding: 8px 0;
    border-bottom: 1px solid var(--border);
}
.info-label { color: var(--text-secondary); font-size: 13px; }
.info-value { font-size: 13px; font-weight: 500; }
.hidden { display: none !important; }
.notification {
    position: fixed;
    top: 20px;
    right: 20px;
    padding: 16px 24px;
    background: var(--bg-dark);
    border: 1px solid var(--border);
    border-radius: 8px;
    box-shadow: 0 4px 12px rgba(0,0,0,0.3);
    z-index: 1000;
}
.notification.success { border-color: var(--success); }
.notification.error { border-color: var(--danger); }
@media (max-width: 1024px) {
    .side-panel { width: 240px; }
    .info-panel { display: none; }
}
@media (max-width: 768px) {
    .side-panel { display: none; }
    .dialpad-btn { width: 60px; height: 60px; font-size: 20px; }
    .number-input { width: 250px; }
}

.modal {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 100%;
    background: rgba(0,0,0,0.7);
    display: flex;
    align-items: center;
    justify-content: center;
    z-index: 1000;
}
.modal-content {
    background: var(--bg-dark);
    border-radius: 12px;
    width: 400px;
    max-width: 90%;
}
.modal-header {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 16px 20px;
    border-bottom: 1px solid var(--border);
}
.modal-header h2 {
    font-size: 18px;
    display: flex;
    align-items: center;
    gap: 8px;
}
.btn-close {
    background: none;
    border: none;
    color: var(--text-secondary);
    font-size: 24px;
    cursor: pointer;
}
.modal-body {
    padding: 20px;
}
.setting-group {
    margin-bottom: 16px;
}
.setting-group label {
    display: flex;
    align-items: center;
    gap: 8px;
    color: var(--text-secondary);
    font-size: 14px;
}
.setting-group select, .setting-group input[type="text"] {
    width: 100%;
    padding: 10px;
    background: var(--bg-light);
    border: 1px solid var(--border);
    border-radius: 8px;
    color: var(--text-primary);
    margin-top: 8px;
}