static/styles.css

:root {
    --text-main: #ecf6ff;
    --text-muted: #a5c6d9;
    --surface: rgba(9, 30, 44, 0.80);
    --surface-soft: rgba(255, 255, 255, 0.08);
    --surface-strong: rgba(255, 255, 255, 0.13);
    --border: rgba(133, 205, 236, 0.22);
    --accent: #25c88d;
    --accent-hover: #1fb078;
    --assistant-bg: rgba(15, 44, 63, 0.82);
    --user-bg: linear-gradient(120deg, #1ec18a, #1ca675);
    --danger-bg: rgba(255, 92, 92, 0.15);
    --danger-border: rgba(255, 92, 92, 0.45);
    --danger-text: #ffd7d7;
}

* {
    box-sizing: border-box;
    margin: 0;
    padding: 0;
    font-family: "Segoe UI", "Helvetica Neue", Arial, sans-serif;
}

html,
body {
    width: 100%;
    height: 100%;
    overflow: hidden;
}

body {
    color: var(--text-main);
    background: #04121e;
}

.background-image {
    position: fixed;
    inset: 0;
    z-index: -2;
    background: url('background.jpeg') center/cover no-repeat;
    transform: scale(1.02);
}

.background-overlay {
    position: fixed;
    inset: 0;
    z-index: -1;
    background:
        radial-gradient(circle at 18% 18%, rgba(55, 197, 187, 0.22), transparent 45%),
        radial-gradient(circle at 80% 82%, rgba(6, 170, 140, 0.30), transparent 40%),
        linear-gradient(145deg, rgba(3, 13, 23, 0.78), rgba(3, 13, 23, 0.44));
}

.site-header {
    position: fixed;
    top: 0;
    left: 0;
    width: 100%;
    height: 92px;
    padding: 10px 28px;
    display: flex;
    align-items: center;
    justify-content: space-between;
    z-index: 10;
    background: linear-gradient(to bottom, rgba(4, 12, 19, 0.56), rgba(4, 12, 19, 0.06));
    backdrop-filter: blur(6px);
}

.logo img {
    height: 76px;
    width: auto;
}

.site-header nav {
    display: flex;
    align-items: center;
    gap: 24px;
}

.site-header nav a {
    color: #e9f7ff;
    text-decoration: none;
    font-size: 1.1rem;
    font-weight: 600;
    letter-spacing: 0.01em;
    transition: color 0.2s ease;
}

.site-header nav a:hover {
    color: #74f2c5;
}

.hero-layout {
    height: 100vh;
    width: 100%;
    padding: 112px 28px 24px;
    display: grid;
    grid-template-columns: minmax(360px, 1fr) minmax(470px, 520px);
    gap: 30px;
    align-items: center;
}

.hero-copy {
    max-width: 760px;
    padding: 18px 8px 18px 4px;
}

.hero-kicker {
    margin-bottom: 10px;
    color: #8ed8f9;
    font-size: clamp(1rem, 1.4vw, 1.28rem);
    letter-spacing: 0.12em;
    text-transform: uppercase;
    font-weight: 700;
}

.hero-copy h1 {
    font-size: clamp(3.35rem, 6.2vw, 6.3rem);
    line-height: 0.95;
    text-shadow: 0 10px 30px rgba(2, 8, 15, 0.5);
    margin-bottom: 20px;
}

.hero-subtitle {
    max-width: 58ch;
    color: var(--text-muted);
    font-size: 1.08rem;
    line-height: 1.6;
    text-shadow: 0 4px 20px rgba(0, 0, 0, 0.4);
}

.chatbot-container {
    width: 100%;
    height: calc(100vh - 150px);
    min-height: 640px;
    max-height: 860px;
}

.card {
    height: 100%;
    display: flex;
    flex-direction: column;
    border-radius: 24px;
    border: 1px solid var(--border);
    background: var(--surface);
    backdrop-filter: blur(12px);
    box-shadow: 0 22px 70px rgba(2, 8, 18, 0.65);
    overflow: hidden;
}

.card-header {
    padding: 18px 20px;
    border-bottom: 1px solid var(--border);
    background: linear-gradient(145deg, rgba(255, 255, 255, 0.06), rgba(255, 255, 255, 0.02));
}

.chatbot-brand {
    display: flex;
    align-items: center;
    gap: 12px;
}

.chatbot-brand img {
    width: 58px;
    height: 58px;
    object-fit: contain;
    border-radius: 12px;
    background: rgba(255, 255, 255, 0.12);
    border: 1px solid var(--border);
    padding: 3px;
}

.chatbot-brand h2 {
    font-size: 1.08rem;
    margin-bottom: 2px;
}

.chatbot-brand p {
    font-size: 0.86rem;
    color: #93d7f3;
}

.msg_card_body {
    flex: 1;
    overflow-y: auto;
    padding: 20px 18px;
    scrollbar-width: thin;
    scrollbar-color: rgba(85, 193, 167, 0.7) transparent;
}

.msg_card_body::-webkit-scrollbar {
    width: 8px;
}

.msg_card_body::-webkit-scrollbar-thumb {
    background: rgba(85, 193, 167, 0.7);
    border-radius: 20px;
}

.card-footer {
    border-top: 1px solid var(--border);
    padding: 14px;
    background: linear-gradient(180deg, rgba(255, 255, 255, 0.03), rgba(255, 255, 255, 0.08));
}

.input-group {
    display: flex;
    align-items: flex-end;
    gap: 10px;
}

.type_msg {
    flex: 1;
    min-height: 56px;
    max-height: 120px;
    border: 1px solid var(--border);
    border-radius: 18px;
    padding: 14px 16px;
    color: #eef8ff;
    background: rgba(6, 31, 47, 0.72);
    resize: none;
    font-size: 0.97rem;
    line-height: 1.4;
    outline: none;
}

.type_msg::placeholder {
    color: #89abc1;
}

.type_msg:focus {
    border-color: rgba(67, 225, 174, 0.7);
    box-shadow: 0 0 0 2px rgba(58, 198, 157, 0.2);
}

.input-group-append {
    display: flex;
    gap: 8px;
}

.send_btn {
    width: 48px;
    height: 48px;
    border: none;
    border-radius: 14px;
    background: rgba(6, 32, 48, 0.84);
    color: #72e4b8;
    font-size: 1.06rem;
    cursor: pointer;
    display: inline-flex;
    align-items: center;
    justify-content: center;
    transition: transform 0.2s ease, background-color 0.2s ease, color 0.2s ease;
}

.send_btn:hover {
    transform: translateY(-1px);
    color: #f2fffb;
    background: var(--accent);
}

.d-flex {
    display: flex;
}

.justify-content-start {
    justify-content: flex-start;
}

.justify-content-end {
    justify-content: flex-end;
}

.mb-4 {
    margin-bottom: 12px;
}

.msg_cotainer,
.msg_cotainer_send {
    max-width: 92%;
    border-radius: 16px;
    padding: 12px 14px;
    box-shadow: 0 8px 24px rgba(4, 13, 20, 0.36);
}

.msg_cotainer {
    color: #eaf9ff;
    background: var(--assistant-bg);
    border: 1px solid var(--border);
}

.msg_cotainer_send {
    color: #f3fffb;
    background: var(--user-bg);
}

.error-bubble {
    background: var(--danger-bg);
    border: 1px solid var(--danger-border);
    color: var(--danger-text);
}

@media (max-width: 1180px) {
    .site-header nav {
        gap: 15px;
    }

    .site-header nav a {
        font-size: 0.96rem;
    }

    .hero-layout {
        grid-template-columns: 1fr minmax(430px, 500px);
    }
}

@media (max-width: 980px) {
    .site-header {
        height: 84px;
        padding: 8px 18px;
    }

    .logo img {
        height: 62px;
    }

    .site-header nav {
        display: none;
    }

    .hero-layout {
        grid-template-columns: 1fr;
        padding: 92px 14px 12px;
        gap: 14px;
        align-items: stretch;
    }

    .hero-copy {
        max-width: none;
        padding: 4px;
    }

    .hero-copy h1 {
        font-size: clamp(2.4rem, 8vw, 3.9rem);
        line-height: 0.98;
    }

    .hero-subtitle {
        font-size: 0.95rem;
    }

    .chatbot-container {
        width: 100%;
        height: calc(100vh - 250px);
        min-height: 0;
    }
}

@media (max-width: 700px) {
    .hero-layout {
        padding: 86px 8px 8px;
    }

    .hero-copy {
        display: none;
    }

    .chatbot-container {
        height: calc(100vh - 96px);
    }

    .card {
        border-radius: 18px;
    }

    .card-header {
        padding: 14px;
    }

    .chatbot-brand img {
        width: 50px;
        height: 50px;
    }

    .chatbot-brand h2 {
        font-size: 0.98rem;
    }

    .chatbot-brand p {
        font-size: 0.78rem;
    }

    .msg_card_body {
        padding: 14px 12px;
    }

    .card-footer {
        padding: 10px;
    }

    .type_msg {
        min-height: 52px;
        font-size: 0.92rem;
    }

    .send_btn {
        width: 44px;
        height: 44px;
    }
}