:root {
    --background-color: #000000;
    --text-color: #FFFFFF;
    --placeholder-color: #444;
    --input-bg-color: #1c1c1e;
    --panel-bg-color: #1c1c1e;
    --button-color: #007aff;
    --border-color: #333;
}

html, body {
    margin: 0;
    padding: 0;
    width: 100%;
    height: 100%;
    overflow: hidden;
    font-family: -apple-system, "Hiragino Kaku Gothic ProN", "Hiragino Sans", Meiryo, sans-serif;
    background-color: var(--background-color);
    color: var(--text-color);
}

.app-container {
    display: flex;
    flex-direction: column;
    width: 100%;
    height: 100%;
    padding: env(safe-area-inset-top) env(safe-area-inset-right) env(safe-area-inset-bottom) env(safe-area-inset-left);
    box-sizing: border-box;
}

.input-area {
    display: flex;
    padding: 15px;
    gap: 10px;
}

#main-input {
    flex-grow: 1;
    background-color: var(--input-bg-color);
    border: 1px solid var(--border-color);
    color: var(--text-color);
    font-size: 18px;
    padding: 10px 15px;
    border-radius: 10px;
    caret-color: var(--button-color);
}

#main-input::placeholder {
    color: var(--placeholder-color);
}

#main-input:focus {
    outline: none;
    border-color: var(--button-color);
}

#display-area {
    flex-grow: 1;
    display: flex;
    justify-content: center;
    align-items: center;
    width: 100%;
    /* Height is managed by flex-grow */
    overflow: hidden; /* Prevent content from spilling out */
    text-align: center;
}

#display-text {
    /* font-size is now set dynamically by JavaScript */
    font-weight: bold;
    line-height: 1;
    padding: 0 10px; /* Add some padding */
    box-sizing: border-box;
}

button {
    background-color: var(--button-color);
    color: white;
    border: none;
    padding: 0 20px;
    font-size: 16px;
    border-radius: 10px;
    cursor: pointer;
}

/* History Panel */
#history-panel {
    position: fixed;
    bottom: 0;
    left: 0;
    right: 0;
    height: 40%;
    background-color: var(--panel-bg-color);
    border-top: 1px solid var(--border-color);
    transform: translateY(100%);
    transition: transform 0.3s ease-in-out;
    display: flex;
    flex-direction: column;
    padding: 15px;
    padding-bottom: calc(15px + env(safe-area-inset-bottom));
    box-sizing: border-box;
    z-index: 100;
}

.history-panel-visible {
    transform: translateY(0) !important;
}

#history-panel h2 {
    margin: 0 0 10px 0;
    font-size: 20px;
}

#history-list {
    list-style: none;
    padding: 0;
    margin: 0;
    flex-grow: 1;
    overflow-y: auto;
}

#history-list li {
    display: flex;
    justify-content: space-between;
    align-items: center;
    padding: 15px 10px;
    border-bottom: 1px solid var(--border-color);
    font-size: 22px;
    cursor: pointer;
}

#history-list li:first-child {
    border-top: 1px solid var(--border-color);
}

.delete-history-item {
    background-color: #ff3b30;
    color: white;
    border: none;
    border-radius: 50%;
    width: 30px;
    height: 30px;
    font-size: 16px;
    line-height: 30px;
    text-align: center;
    cursor: pointer;
}

#history-close-button {
    margin-top: 10px;
    padding: 15px;
    font-size: 18px;
    font-weight: bold;
}