:root {
    --wa-green-dark: #075E54;
    --wa-green: #128C7E;
    --wa-green-light: #25D366;
    --wa-bg: #ECE5DD;
    --wa-bubble-out: #DCF8C6;
    --wa-bubble-in: #FFFFFF;
    --wa-text: #111B21;
    --wa-muted: #667781;
    --wa-border: rgba(0, 0, 0, 0.08);
    --wa-shadow: 0 1px 0.5px rgba(0, 0, 0, 0.13);
    --wa-error: #B00020;
}

* {
    box-sizing: border-box;
}

[hidden] {
    display: none !important;
}

html, body {
    margin: 0;
    padding: 0;
    height: 100%;
    font-family: -apple-system, BlinkMacSystemFont, "Segoe UI", Roboto, "Helvetica Neue", Arial, sans-serif;
    color: var(--wa-text);
    background: var(--wa-bg);
}

.screen {
    min-height: 100vh;
    display: flex;
    flex-direction: column;
}

/* ---------- Login ---------- */

.login-screen {
    align-items: center;
    justify-content: center;
    background: linear-gradient(180deg, var(--wa-green-dark) 0%, var(--wa-green-dark) 220px, #F0F2F5 220px, #F0F2F5 100%);
    padding: 24px;
}

.login-card {
    width: 100%;
    max-width: 420px;
    background: #FFFFFF;
    border-radius: 12px;
    padding: 32px 28px;
    box-shadow: 0 12px 40px rgba(0, 0, 0, 0.15);
}

.login-brand {
    text-align: center;
    margin-bottom: 24px;
}

.brand-circle {
    width: 64px;
    height: 64px;
    border-radius: 50%;
    background: var(--wa-green);
    display: inline-flex;
    align-items: center;
    justify-content: center;
    margin-bottom: 16px;
}

.login-brand h1 {
    margin: 0 0 6px;
    font-size: 22px;
    font-weight: 600;
}

.muted {
    color: var(--wa-muted);
    font-size: 14px;
    margin: 0;
}

.muted.small {
    font-size: 13px;
    margin-bottom: 18px;
}

.step {
    display: flex;
    flex-direction: column;
    gap: 14px;
}

.field {
    display: flex;
    flex-direction: column;
    gap: 6px;
    font-size: 13px;
    color: var(--wa-muted);
}

.field input,
.field select {
    width: 100%;
    padding: 10px 12px;
    border: 1px solid #D1D7DB;
    border-radius: 8px;
    font-size: 15px;
    color: var(--wa-text);
    background: #FFFFFF;
    transition: border-color 0.15s ease, box-shadow 0.15s ease;
}

.field input:focus,
.field select:focus {
    outline: none;
    border-color: var(--wa-green);
    box-shadow: 0 0 0 3px rgba(18, 140, 126, 0.15);
}

.btn-primary {
    background: var(--wa-green);
    color: #FFFFFF;
    border: none;
    border-radius: 24px;
    padding: 12px 18px;
    font-size: 15px;
    font-weight: 600;
    cursor: pointer;
    transition: background-color 0.15s ease, transform 0.05s ease;
}

.btn-primary:hover:not(:disabled) {
    background: var(--wa-green-dark);
}

.btn-primary:active:not(:disabled) {
    transform: scale(0.99);
}

.btn-primary:disabled {
    opacity: 0.6;
    cursor: progress;
}

.btn-link {
    background: none;
    border: none;
    color: var(--wa-green);
    font-size: 14px;
    cursor: pointer;
    padding: 4px;
}

.btn-link:hover {
    text-decoration: underline;
}

.error {
    color: var(--wa-error);
    font-size: 13px;
    margin: 14px 0 0;
    text-align: center;
}

/* ---------- Chat ---------- */

.chat-screen {
    height: 100vh;
    min-height: 0;
    overflow: hidden;
    background: var(--wa-bg);
    background-image:
        radial-gradient(circle at 20% 25%, rgba(255, 255, 255, 0.5) 1px, transparent 1px),
        radial-gradient(circle at 80% 75%, rgba(255, 255, 255, 0.4) 1px, transparent 1px);
    background-size: 36px 36px, 48px 48px;
}

.chat-header {
    display: flex;
    align-items: center;
    gap: 12px;
    padding: 10px 16px;
    background: var(--wa-green-dark);
    color: #FFFFFF;
    box-shadow: 0 2px 4px rgba(0, 0, 0, 0.15);
    position: sticky;
    top: 0;
    z-index: 10;
}

.avatar {
    width: 40px;
    height: 40px;
    border-radius: 50%;
    background: var(--wa-green-light);
    color: #FFFFFF;
    display: flex;
    align-items: center;
    justify-content: center;
    font-weight: 700;
    font-size: 14px;
}

.chat-header .meta {
    flex: 1;
    min-width: 0;
}

.chat-header .name {
    font-weight: 600;
    font-size: 16px;
}

.chat-header .phone {
    font-size: 12px;
    opacity: 0.8;
}

.btn-icon {
    background: none;
    border: none;
    color: #FFFFFF;
    cursor: pointer;
    padding: 6px;
    border-radius: 50%;
    display: flex;
    align-items: center;
    justify-content: center;
    transition: background-color 0.15s ease;
}

.btn-icon:hover {
    background: rgba(255, 255, 255, 0.12);
}

.messages {
    flex: 1;
    overflow-y: auto;
    padding: 16px 12px;
    display: flex;
    flex-direction: column;
    gap: 4px;
}

.bubble {
    max-width: min(75%, 560px);
    padding: 6px 10px 6px;
    border-radius: 8px;
    box-shadow: var(--wa-shadow);
    font-size: 14.5px;
    line-height: 1.4;
    word-wrap: break-word;
    white-space: pre-wrap;
}

.bubble.incoming {
    background: var(--wa-bubble-in);
    align-self: flex-start;
    border-top-left-radius: 0;
    margin-left: 8px;
}

.bubble.outgoing {
    background: var(--wa-bubble-out);
    align-self: flex-end;
    border-top-right-radius: 0;
    margin-right: 8px;
}

.bubble .time {
    margin-top: 2px;
    text-align: right;
    font-size: 11px;
    color: var(--wa-muted);
    white-space: nowrap;
}

.bubble + .bubble.incoming,
.bubble + .bubble.outgoing {
    margin-top: 2px;
}

.empty-state {
    align-self: center;
    margin: auto;
    padding: 12px 18px;
    background: rgba(225, 245, 254, 0.85);
    border-radius: 8px;
    color: var(--wa-muted);
    font-size: 13px;
    text-align: center;
}

.chat-composer {
    display: flex;
    align-items: center;
    gap: 8px;
    padding: 8px 12px;
    background: #F0F2F5;
    border-top: 1px solid var(--wa-border);
    flex-shrink: 0;
}

.chat-composer input {
    flex: 1;
    padding: 10px 16px;
    border: none;
    border-radius: 24px;
    background: #FFFFFF;
    font-size: 15px;
    color: var(--wa-text);
    box-shadow: var(--wa-shadow);
}

.chat-composer input:focus {
    outline: none;
    box-shadow: 0 0 0 2px rgba(18, 140, 126, 0.25);
}

.btn-send {
    width: 42px;
    height: 42px;
    border-radius: 50%;
    border: none;
    background: var(--wa-green);
    color: #FFFFFF;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: background-color 0.15s ease, transform 0.05s ease;
}

.btn-send:hover:not(:disabled) {
    background: var(--wa-green-dark);
}

.btn-send:active:not(:disabled) {
    transform: scale(0.96);
}

.btn-send:disabled {
    opacity: 0.55;
    cursor: not-allowed;
}

/* ---------- Responsive ---------- */

@media (max-width: 480px) {
    .login-card {
        padding: 24px 20px;
    }

    .bubble {
        max-width: 85%;
    }
}