/* ===== CSS Variables ===== */
:root {
    --bg: #f5f5f5;
    --bg2: #ffffff;
    --bg3: #e8e8e8;
    --text: #1a1a1a;
    --text2: #555;
    --border: #ddd;
    --primary: #6c63ff;
    --primary-hover: #5a52d5;
    --bot-bg: #ffffff;
    --bot-text: #1a1a1a;
    --shadow: 0 2px 12px rgba(0,0,0,0.08);
    --radius: 18px;
    --radius-sm: 8px;
    --header-h: 64px;
}

body.dark {
    --bg: #0f0f0f;
    --bg2: #1a1a1a;
    --bg3: #252525;
    --text: #f0f0f0;
    --text2: #aaa;
    --border: #333;
    --bot-bg: #1e1e1e;
    --bot-text: #f0f0f0;
    --shadow: 0 2px 12px rgba(0,0,0,0.4);
}

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

body {
    font-family: -apple-system, BlinkMacSystemFont, 'Segoe UI', sans-serif;
    background: var(--bg);
    color: var(--text);
    height: 100dvh;
    overflow: hidden;
    transition: background 0.3s, color 0.3s;
}

/* ===== App Layout ===== */
.app {
    display: flex;
    flex-direction: column;
    height: 100dvh;
    max-width: 800px;
    margin: 0 auto;
}

/* ===== Header ===== */
.header {
    display: flex;
    align-items: center;
    justify-content: space-between;
    padding: 0 16px;
    height: var(--header-h);
    background: var(--bg2);
    border-bottom: 1px solid var(--border);
    flex-shrink: 0;
    box-shadow: var(--shadow);
    z-index: 10;
}

.header-left {
    display: flex;
    align-items: center;
    gap: 12px;
}

.logo { font-size: 28px; }

.header-left h1 {
    font-size: 18px;
    font-weight: 700;
}

.model-badge {
    display: inline-block;
    font-size: 11px;
    font-weight: 600;
    color: var(--primary);
    background: color-mix(in srgb, var(--primary) 12%, transparent);
    border: 1px solid color-mix(in srgb, var(--primary) 30%, transparent);
    padding: 2px 8px;
    border-radius: 20px;
}

.header-right {
    display: flex;
    gap: 4px;
}

.icon-btn {
    background: none;
    border: none;
    cursor: pointer;
    font-size: 18px;
    padding: 8px;
    border-radius: var(--radius-sm);
    transition: background 0.2s;
}

.icon-btn:hover { background: var(--bg3); }

/* ===== Chat Area ===== */
.chat-area {
    flex: 1;
    overflow-y: auto;
    padding: 20px 16px;
    display: flex;
    flex-direction: column;
    gap: 12px;
    scroll-behavior: smooth;
}

/* ===== Welcome Screen ===== */
.welcome {
    margin: auto;
    text-align: center;
    padding: 20px;
    max-width: 480px;
}

.welcome-icon {
    font-size: 56px;
    margin-bottom: 16px;
}

.welcome h2 {
    font-size: 24px;
    margin-bottom: 8px;
}

.welcome p {
    color: var(--text2);
    line-height: 1.6;
    margin-bottom: 6px;
}

.welcome .tip {
    font-size: 13px;
    margin-bottom: 20px;
}

.example-prompts {
    display: flex;
    flex-direction: column;
    gap: 8px;
    margin-top: 16px;
}

.example-btn {
    background: var(--bg3);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 10px 16px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 13px;
    text-align: left;
    transition: background 0.2s, border-color 0.2s;
}

.example-btn:hover {
    background: color-mix(in srgb, var(--primary) 10%, var(--bg3));
    border-color: var(--primary);
    color: var(--primary);
}

/* ===== Messages ===== */
.message {
    display: flex;
    gap: 10px;
    max-width: 100%;
    animation: fadeUp 0.2s ease;
}

@keyframes fadeUp {
    from { opacity: 0; transform: translateY(8px); }
    to   { opacity: 1; transform: translateY(0); }
}

.message.user { flex-direction: row-reverse; }

.message .avatar {
    width: 32px;
    height: 32px;
    border-radius: 50%;
    font-size: 16px;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    background: var(--bg3);
    margin-top: 2px;
}

.message.user .avatar { background: var(--primary); }

.bubble {
    max-width: calc(100% - 48px);
    padding: 12px 16px;
    border-radius: var(--radius);
    line-height: 1.65;
    font-size: 15px;
    word-break: break-word;
}

.message.user .bubble {
    background: var(--primary);
    color: #fff;
    border-bottom-right-radius: 4px;
}

.message.assistant .bubble {
    background: var(--bot-bg);
    color: var(--bot-text);
    border-bottom-left-radius: 4px;
    box-shadow: var(--shadow);
}

.message.error .bubble {
    background: rgba(255, 77, 77, 0.1);
    border: 1px solid rgba(255, 77, 77, 0.3);
    color: #ff6b6b;
}

/* Code blocks */
.bubble pre {
    background: var(--bg);
    border: 1px solid var(--border);
    border-radius: var(--radius-sm);
    padding: 12px;
    overflow-x: auto;
    margin: 8px 0;
    font-size: 13px;
}

.bubble code {
    font-family: 'Menlo', 'Consolas', monospace;
    font-size: 13px;
    background: var(--bg3);
    padding: 2px 5px;
    border-radius: 4px;
}

.bubble pre code {
    background: none;
    padding: 0;
}

/* ===== Loading Dots ===== */
.loading-dots {
    display: flex;
    gap: 5px;
    align-items: center;
    padding: 4px 0;
}

.loading-dots span {
    width: 8px;
    height: 8px;
    background: var(--text2);
    border-radius: 50%;
    animation: bounce 1.2s infinite;
}

.loading-dots span:nth-child(2) { animation-delay: 0.2s; }
.loading-dots span:nth-child(3) { animation-delay: 0.4s; }

@keyframes bounce {
    0%, 60%, 100% { transform: translateY(0); opacity: 0.4; }
    30%            { transform: translateY(-6px); opacity: 1; }
}

/* ===== Input Area ===== */
.input-area {
    padding: 12px 16px 16px;
    background: var(--bg2);
    border-top: 1px solid var(--border);
    flex-shrink: 0;
}

.input-wrapper {
    display: flex;
    align-items: flex-end;
    gap: 8px;
    background: var(--bg3);
    border: 1.5px solid var(--border);
    border-radius: var(--radius);
    padding: 10px 10px 10px 16px;
    transition: border-color 0.2s;
}

.input-wrapper:focus-within { border-color: var(--primary); }

textarea#user-input {
    flex: 1;
    background: none;
    border: none;
    outline: none;
    color: var(--text);
    font-size: 15px;
    font-family: inherit;
    resize: none;
    max-height: 200px;
    line-height: 1.5;
}

textarea#user-input::placeholder { color: var(--text2); }

.send-btn {
    background: var(--primary);
    border: none;
    color: #fff;
    width: 36px;
    height: 36px;
    border-radius: 50%;
    cursor: pointer;
    display: flex;
    align-items: center;
    justify-content: center;
    flex-shrink: 0;
    transition: background 0.2s, transform 0.1s;
}

.send-btn:hover:not(:disabled) { background: var(--primary-hover); }
.send-btn:active:not(:disabled) { transform: scale(0.92); }

.send-btn:disabled {
    background: var(--bg3);
    color: var(--text2);
    cursor: not-allowed;
}

.send-btn.stop-mode {
    background: #e53e3e;
}

.send-btn.stop-mode:hover {
    background: #c53030;
}

.disclaimer {
    font-size: 11px;
    color: var(--text2);
    text-align: center;
    margin-top: 8px;
}

/* ===== Modal ===== */
.modal-overlay {
    display: none;
    position: fixed;
    inset: 0;
    background: rgba(0,0,0,0.6);
    z-index: 100;
    align-items: center;
    justify-content: center;
    backdrop-filter: blur(4px);
}

.modal-overlay.show { display: flex; }

.modal {
    background: var(--bg2);
    border: 1px solid var(--border);
    border-radius: 16px;
    padding: 28px;
    width: min(480px, calc(100vw - 32px));
    box-shadow: 0 20px 60px rgba(0,0,0,0.3);
    animation: modalIn 0.2s ease;
}

@keyframes modalIn {
    from { opacity: 0; transform: scale(0.95) translateY(-10px); }
    to   { opacity: 1; transform: scale(1) translateY(0); }
}

.modal h2 { margin-bottom: 20px; font-size: 20px; }

.form-group { margin-bottom: 16px; }

.form-group label {
    display: block;
    font-size: 13px;
    font-weight: 600;
    color: var(--text2);
    margin-bottom: 6px;
    text-transform: uppercase;
    letter-spacing: 0.5px;
}

.key-wrapper { display: flex; gap: 6px; }

.form-group input,
.form-group select,
.form-group textarea {
    width: 100%;
    background: var(--bg3);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 10px 14px;
    border-radius: var(--radius-sm);
    font-size: 14px;
    font-family: inherit;
    outline: none;
    transition: border-color 0.2s;
}

.form-group input:focus,
.form-group select:focus,
.form-group textarea:focus { border-color: var(--primary); }

.form-group textarea { resize: vertical; }

.eye-btn {
    background: var(--bg3);
    border: 1px solid var(--border);
    color: var(--text);
    padding: 0 12px;
    border-radius: var(--radius-sm);
    cursor: pointer;
    font-size: 16px;
    flex-shrink: 0;
}

.modal-buttons {
    display: flex;
    gap: 10px;
    justify-content: flex-end;
    margin-top: 24px;
}

.btn-cancel, .btn-save {
    padding: 10px 20px;
    border-radius: var(--radius-sm);
    border: none;
    cursor: pointer;
    font-size: 14px;
    font-weight: 600;
    transition: background 0.2s;
}

.btn-cancel { background: var(--bg3); color: var(--text); }
.btn-cancel:hover { background: var(--border); }
.btn-save { background: var(--primary); color: #fff; }
.btn-save:hover { background: var(--primary-hover); }

/* ===== Scrollbar ===== */
::-webkit-scrollbar { width: 6px; }
::-webkit-scrollbar-track { background: transparent; }
::-webkit-scrollbar-thumb { background: var(--border); border-radius: 3px; }
::-webkit-scrollbar-thumb:hover { background: var(--text2); }

/* ===== Mobile ===== */
@media (max-width: 600px) {
    .header-left h1 { font-size: 16px; }
    .bubble { font-size: 14px; }
    .example-prompts { display: none; }
}